The use of systemic chemotherapy and estrogen ablation (EA) for the treatment of breast cancer historically have been based on both the histologic prognostic parameters of the invasive breast cancer and on traditional estimates of recurrence risk. These estimates take into account the patient’s age, tumor size, grade, lymphovascular invasion, hormonal receptor status (estrogen receptor/progesterone receptor [ER/PR]), and human epidermal growth factor receptor 2 (HER2) overexpression.¹

The recent description of 4 primary breast cancer subtypes on the basis of gene expression profiles has led to the identification of more specific gene prognostic signatures.² These may serve to supplement, and possibly supersede, the assessment of recurrence risk currently employed as the basis for chemotherapy or EA recommendations for patients with breast cancer. As a result, many
patients who would have been treated with chemotherapy previously may now safely avoid it. The information provided by these prognostic signatures may also alter surgical decision making for many patients and, consequently, should be within the purview of dedicated cancer surgeons.

BREAST CANCER SUBTYPES

The 4 breast cancer subtypes are (1) the HER2 type, these can be ER/PR positive or negative; (2) basal-like tumors, typically ER, PR, and HER2 negative (ER-, PR-, and HER2-); and ER-positive (ER+) or luminal tumors, usually divided into (3) luminal A and (4) luminal B.²

HER2 Type

The advent of the first targeted breast cancer therapy, trastuzumab, and its immense salutary effect on survival of patients with previously poor prognoses has made the use of chemotherapy in combination with trastuzumab nearly mandatory in all HER2+ patients with breast cancer. Remarkably, the huge improvement in survival of these formerly doomed patients has led to the recommendation that trastuzumab-containing chemotherapy regimens should be used in the management of even subcentimeter, node-negative patients.³ This recommendation represents a clear change from the traditional recommendations for chemotherapy, which held that the benefits of systemic chemotherapy were more likely to be seen in patients with tumors in excess of 1 cm and/or who were node positive.

Basal-like Tumors

The discovery of trastuzumab made the basal-like tumor, which is usually ER-, PR-, and HER2- (triple negative), the subtype with the worst prognosis. Further, the natural course of this illness is markedly different from that of ER+/PR+ breast cancer. Nearly all basal-like or triple-negative patients with breast cancer who experience a recurrence do so within the first 5 years after diagnosis.⁴ In contrast, nearly 40% of ER+/PR+ HER2- breast cancer survivors experience their first recurrence beyond the 5-year milestone, with many even later in their course.⁵ Thus, the patient with triple-negative breast cancer is more likely to benefit from chemotherapy predominantly during the first 5 post-diagnosis years, as suggested by the Early Breast Cancer Trialists’ Collaborative Group meta-analyses.¹

HER2+ and triple-negative breast cancers account for 20% and 15% of all breast cancers, respectively.^6,7 In both subtypes, the benefit of chemotherapy is immense and chemotherapy will rarely be omitted from the treatment plan. Many of these patients are considered ideal candidates for preoperative chemotherapy (PCT), which results in increased rates of breast-conserving surgery (BCS), decreased positive margin rates at BCS, and decreased need for axillary node dissection. In the setting of PCT, a pathologic complete response (pCR) in the breast and axilla is increasingly recognized as a marker for improved disease-free survival (DFS) and overall survival (OS).⁸ For these reasons, preoperative consultation with medical oncologists is now even more important. Many of these patients will benefit from the use of PCT before any surgical treatment is undertaken.

Luminal Type (A and B)

The remaining two-thirds of all patients with breast cancer are ER+, primarily postmenopausal, and fall within the 2 remaining molecular subtypes: luminal A and luminal B. It is for these patients that the relative benefits of chemotherapy vs EA, or both, are currently being debated. For these patients the use of gene prognostic signatures, in concert with traditional histopathologic and clinical risk factors, may alter estimates of recurrence risk and the impact of chemotherapy on survival and recurrence estimates.

It is now evident that even the strongest predictors for breast cancer recurrence—histologic grade, patient age, and nodal status—are inconsistent predictors of the behavior of any individual tumor. While the use of chemotherapy can reduce the risk of metastases in these luminal-type patients with breast cancer, the majority of patients so stratified would survive without chemotherapy.⁹

GENE EXPRESSION SIGNATURE ASSAYS

One of the best demonstrations of the shortcomings of the standard risk predictors for ER+, HER2- breast cancers is provided by the Oncotype DX breast cancer assay’s recurrence score (RS) or gene expression signature (GES).^10,11

Oncotype DX

The Oncotype DX assay is the first commercially available GES assay to illustrate the variability in survival of patients with node-negative, ER+ breast tumors. Sixteen selected cancer proliferative genes are paired with 5 control nonproliferative genes whose relative activity can be measured in paraffin-embedded breast cancer tissue. The ability to retrieve reliable ribonucleic acid (RNA) expression from cancer cells embedded in paraffin was a stroke of genius; it enabled the investigators to correlate the gene expression profile of patient subgroups treated decades earlier with their long-term clinical outcomes and survival. 

The normalized summation of the proliferative activity of the 16 cancerproliferation genes in the Oncotype DX assay is expressed as the RS. The RS increases linearly and so does the average rate of distant recurrence in 10 years as a function of the RS. Three risk recurrence groups are defined by the RS: low risk (RS < 18); intermediate risk (RS > 18 to 30); and high risk (RS > 31).^10,11

Clinical Trials

In the National Surgical Adjuvant Breast and Bowel Project (NSABP) clinical trial B-14, ER+ node-negative patients were randomized to observation or tamoxifen. In the untreated control patients, a low RS (< 18) was accompanied by a 6.8% risk of metastasis at 10 years, and a high RS (> 31) was accompanied by a 30.5% rate of distant recurrence.¹¹ In another study, the low RS tamoxifen-treated arm showed a 2.8% risk of breast cancer death at 10 years vs a 15.5% risk in the high RS cohort.¹²

The remarkable significance of the RS is demonstrated when the RS is plotted against patient age, grade, or tumor size.¹⁰ This illustrates the huge variability in these traditional histopathologic and clinical features within a given RS group. For any patient with a low RS, there is marked variability in patient age, tumor grade, or tumor size. A very small or low-grade tumor can have a very high 10-year recurrence rate, as measured by the gene prognostic signature or RS. Similarly, a very large tumor in a young patient can have a very low 10-year recurrence rate or RS. This is due to the heterogeneity of the biology of these cancers, regardless of their favorable or unfavorable histologic features.

In most cases, decisions about chemotherapy in patient who are postmenopausal, node-negative, and ER+ are made by risk estimates based on patient age, tumor grade, and tumor size, without knowledge of their RS. However, the large variability in 10-year rates of metastases and death among patients clearly demonstrates that, for some, chemotherapy affords no benefit. Their RS suggest that their risk of metastases at 10 years is only 2.8% when treated with EA (ie, tamoxifen) and no chemotherapy. In fact, 51% of the patients who are postmenopausal, node-negative, and ER+ in NSABP B-14 fell within the low risk RS category for 10-year distant recurrence, whereas about 27% fell within the high risk (RS > 31) category.¹³

Confidence in the Oncotype DX assay RS stems from the ability of investigators to plot the recurrence rates of distant metastases in patientstreated with tamoxifen vs placebo in the NSABP B-14 trial. Their clinicaloutcomes could be correlated with their GES samples retrieved from paraffin-embedded archival tissue many years after treatment. Corresponding plotting was done for similar patient cohorts treated with chemotherapy with or without tamoxifen in NSABP Trial B-20.

Among patients with low RS, the distant recurrence rate at 10 years was 2.2%, whether treated with systemic chemotherapy plus tamoxifenor with tamoxifen alone. Thus, in study participants with low RS, regardless of tumor size, grade, or patient age, 10-year recurrence rates were not affected by the addition of chemotherapy.¹³

Note that, in the absence of the new information provided by the Oncotype gene prognostic signature, nearly all these patients would be treated with systemic chemotherapy. Studies have shown that the additional risk assessment estimate provided by the Oncotype assay causes a change in systemic therapy recommendations from chemotherapy to no chemotherapy in 30% of patients.^14,15 Among patients with high RS, 10-year distant recurrence rates decreased by an absolute 27% with the addition of chemotherapy to tamoxifen. These patients clearly benefited from chemotherapy.¹³

The relative benefits of chemotherapy vs tamoxifen in a third RS group with an intermediate RS of 18-21 awaits publication of the now-closed Trial Assigning Individualized Options for Treatment (TAILORx) trial. This group accounts for 22% of patients who are postmenopausal, node-negative, and ER+ identified by the Oncotype DX assay. Initial reports show no significant benefit from the addition of chemotherapy to tamoxifen in this group.¹⁰

MammaPrint

Other gene prognostic signatures have recently been validated. Of these, the MammaPrint assay is the best established and validated.¹⁶ The MammaPrint uses a panel of 70 proliferation genes that were selected without bias by scanning the entire human genome. Unlike the Oncotype DX, the MammaPrint panel was randomly selected without any prior knowledge of the role of the proliferation genes in breast carcinogenesis. Furthermore, the reliability of the MammaPrint gene signature is independent of nodal status.¹⁷ This suggests that the intrinsic genetic makeup of the cancer establishes its biologic behavior and supersedes the impact of the traditional assessment of nodal involvement as a significant risk factor for distant metastases.

The MammaPrint GES was developed to identify patients at high risk of recurrence within 5 years of diagnosis; those for whom, as noted earlier, the salutary effect of chemotherapy is most evident.¹⁸ The assay is reliable for both pre- and postmenopausal women and stratifies patients into 2 risk groups only: high vs low.^19-21 The probability of remaining free of recurrent disease at 10 years is 85% in the low risk GES patients vs 50.6% in those with high risk MammaPrint prognosis signatures.¹⁷

Subsequent validation trials examined the accuracy of the MammaPrint as a prognostic indicator as well as a predictor of response to chemotherapy. These studies included node-negative, node-positive, pre- and postmenopausal women.^18-23 The risk of metastatic disease within the first 5 years after diagnosis was more significant in the high-risk than in the low-risk group. However, because the MammaPrint signature is independent of ER status, not all MammaPrint low-risk signatures are ER+. This reflects the contribution of unselected proliferation genes to the MammaPrint signature that results in the luminal A and luminal B breast cancer subtypes. In postmenopausal, node-negative patients, 61% may have good prognosis signatures, regardless of ER status.^18,22

A poor prognosis signature, then, would suggest the use of chemotherapy to prevent early (< 5 years from diagnosis) breast cancer deaths, but would still allow for EA to prevent late (> 5 years after diagnosis) recurrence for patients whose tumors were ER+. It should be noted that these findings also apply to patients treated with contemporary anthracycline chemotherapy regimens.²² The MammaPrint poor prognostic signature identifies patients at risk for early recurrence who may therefore benefit from chemotherapy, whereas the good prognostic signature identifies patients with a very low risk of distant metastases < 5 years.²² In the latter group, this low risk may not warrant use of systemic chemotherapy, but treatment with EA would confer a decrease in systemic metastases.

THE SURGEON’S PERSPECTIVE

To the surgeon, as suggested earlier, perhaps more pertinent is the available information on the use of chemotherapy before planned surgery for basal-type triple negative and HER-2+ breast cancers in the setting of luminal ER+ tumors. Mounting evidence suggests that the GES, such as those determined via the Oncotype and MammaPrint assays, can provide a very reliable indication of an individual patient’s response to PCT or chemotherapy in the neoadjuvant setting.^24,25 These clinical responses are easily quantitated on physical examination or by imaging in the few months during which a patient can receive PCT.

Furthermore, the absence of residual microscopic tumor in the breast and axilla (ie, pCR) after PCT can be predicted by the Oncotype DX RS and the MammaPrint GES. More than 11 reports (5,210 patients) have demonstrated a higher DFS and OS in patients who achieve a pCR after PCT.⁸ A pCR in a locally advanced patient with breast cancer can provide the surgeon with a margin-negative surgical procedure (BCS or mastectomy) and inform the patient of the potential for a much better DFS or OS than anticipated from the stage of breast cancer at presentation. 

In some patients amenable to BCS at presentation but whose tumor is too close to the chest wall or is proximate to a silicone augmentation prosthesis, the predicted response to systemic chemotherapy or hormonal ablation provided by GES can lead to a decrease in margin-positive rates and salvage of the previous cosmetic augmentation.

In patients at risk for carrying a BRCA mutation, the interval of PCT can be used for appropriate genetic testing and counseling and plastic surgery and gynecologic oncology consultations. Identified BRCA gene carriers may benefit from risk reduction surgery because of their increased breast and ovarian cancerrisk. Non-BRCA patients can consider BCS as an option, with decreased margin-positive rates and improved cosmesis. Information provided by GES can be essential to a good surgical outcome and underlines the need for preoperative consultation with medical oncology.²⁶

CONCLUSION

Gene expression signatures provide information about the biologic behavior of each individual patient’s breast cancer.  As new GES are introduced into clinical practice, surgeons must become fully informed about these advances in order to provide truly personalized cancer care plans to our patients.  

Author disclosures
The author reports no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the author and do not necessarily reflect an endorsement by or opinion of Federal Practitioner, Frontline Medical Communications, the U.S. Air Force, the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review complete prescribing information for specific drug combinations­–including indications, contraindications, warnings, and adverse effects–before administering pharmacologic therapy to patients.

The use of systemic chemotherapy and estrogen ablation (EA) for the treatment of breast cancer historically have been based on both the histologic prognostic parameters of the invasive breast cancer and on traditional estimates of recurrence risk. These estimates take into account the patient’s age, tumor size, grade, lymphovascular invasion, hormonal receptor status (estrogen receptor/progesterone receptor [ER/PR]), and human epidermal growth factor receptor 2 (HER2) overexpression.¹

The recent description of 4 primary breast cancer subtypes on the basis of gene expression profiles has led to the identification of more specific gene prognostic signatures.² These may serve to supplement, and possibly supersede, the assessment of recurrence risk currently employed as the basis for chemotherapy or EA recommendations for patients with breast cancer. As a result, many
patients who would have been treated with chemotherapy previously may now safely avoid it. The information provided by these prognostic signatures may also alter surgical decision making for many patients and, consequently, should be within the purview of dedicated cancer surgeons.

BREAST CANCER SUBTYPES

The 4 breast cancer subtypes are (1) the HER2 type, these can be ER/PR positive or negative; (2) basal-like tumors, typically ER, PR, and HER2 negative (ER-, PR-, and HER2-); and ER-positive (ER+) or luminal tumors, usually divided into (3) luminal A and (4) luminal B.²

HER2 Type

The advent of the first targeted breast cancer therapy, trastuzumab, and its immense salutary effect on survival of patients with previously poor prognoses has made the use of chemotherapy in combination with trastuzumab nearly mandatory in all HER2+ patients with breast cancer. Remarkably, the huge improvement in survival of these formerly doomed patients has led to the recommendation that trastuzumab-containing chemotherapy regimens should be used in the management of even subcentimeter, node-negative patients.³ This recommendation represents a clear change from the traditional recommendations for chemotherapy, which held that the benefits of systemic chemotherapy were more likely to be seen in patients with tumors in excess of 1 cm and/or who were node positive.

Basal-like Tumors

The discovery of trastuzumab made the basal-like tumor, which is usually ER-, PR-, and HER2- (triple negative), the subtype with the worst prognosis. Further, the natural course of this illness is markedly different from that of ER+/PR+ breast cancer. Nearly all basal-like or triple-negative patients with breast cancer who experience a recurrence do so within the first 5 years after diagnosis.⁴ In contrast, nearly 40% of ER+/PR+ HER2- breast cancer survivors experience their first recurrence beyond the 5-year milestone, with many even later in their course.⁵ Thus, the patient with triple-negative breast cancer is more likely to benefit from chemotherapy predominantly during the first 5 post-diagnosis years, as suggested by the Early Breast Cancer Trialists’ Collaborative Group meta-analyses.¹

HER2+ and triple-negative breast cancers account for 20% and 15% of all breast cancers, respectively.^6,7 In both subtypes, the benefit of chemotherapy is immense and chemotherapy will rarely be omitted from the treatment plan. Many of these patients are considered ideal candidates for preoperative chemotherapy (PCT), which results in increased rates of breast-conserving surgery (BCS), decreased positive margin rates at BCS, and decreased need for axillary node dissection. In the setting of PCT, a pathologic complete response (pCR) in the breast and axilla is increasingly recognized as a marker for improved disease-free survival (DFS) and overall survival (OS).⁸ For these reasons, preoperative consultation with medical oncologists is now even more important. Many of these patients will benefit from the use of PCT before any surgical treatment is undertaken.

Luminal Type (A and B)

The remaining two-thirds of all patients with breast cancer are ER+, primarily postmenopausal, and fall within the 2 remaining molecular subtypes: luminal A and luminal B. It is for these patients that the relative benefits of chemotherapy vs EA, or both, are currently being debated. For these patients the use of gene prognostic signatures, in concert with traditional histopathologic and clinical risk factors, may alter estimates of recurrence risk and the impact of chemotherapy on survival and recurrence estimates.

It is now evident that even the strongest predictors for breast cancer recurrence—histologic grade, patient age, and nodal status—are inconsistent predictors of the behavior of any individual tumor. While the use of chemotherapy can reduce the risk of metastases in these luminal-type patients with breast cancer, the majority of patients so stratified would survive without chemotherapy.⁹

GENE EXPRESSION SIGNATURE ASSAYS

One of the best demonstrations of the shortcomings of the standard risk predictors for ER+, HER2- breast cancers is provided by the Oncotype DX breast cancer assay’s recurrence score (RS) or gene expression signature (GES).^10,11

Oncotype DX

The Oncotype DX assay is the first commercially available GES assay to illustrate the variability in survival of patients with node-negative, ER+ breast tumors. Sixteen selected cancer proliferative genes are paired with 5 control nonproliferative genes whose relative activity can be measured in paraffin-embedded breast cancer tissue. The ability to retrieve reliable ribonucleic acid (RNA) expression from cancer cells embedded in paraffin was a stroke of genius; it enabled the investigators to correlate the gene expression profile of patient subgroups treated decades earlier with their long-term clinical outcomes and survival. 

The normalized summation of the proliferative activity of the 16 cancerproliferation genes in the Oncotype DX assay is expressed as the RS. The RS increases linearly and so does the average rate of distant recurrence in 10 years as a function of the RS. Three risk recurrence groups are defined by the RS: low risk (RS < 18); intermediate risk (RS > 18 to 30); and high risk (RS > 31).^10,11

Clinical Trials

In the National Surgical Adjuvant Breast and Bowel Project (NSABP) clinical trial B-14, ER+ node-negative patients were randomized to observation or tamoxifen. In the untreated control patients, a low RS (< 18) was accompanied by a 6.8% risk of metastasis at 10 years, and a high RS (> 31) was accompanied by a 30.5% rate of distant recurrence.¹¹ In another study, the low RS tamoxifen-treated arm showed a 2.8% risk of breast cancer death at 10 years vs a 15.5% risk in the high RS cohort.¹²

The remarkable significance of the RS is demonstrated when the RS is plotted against patient age, grade, or tumor size.¹⁰ This illustrates the huge variability in these traditional histopathologic and clinical features within a given RS group. For any patient with a low RS, there is marked variability in patient age, tumor grade, or tumor size. A very small or low-grade tumor can have a very high 10-year recurrence rate, as measured by the gene prognostic signature or RS. Similarly, a very large tumor in a young patient can have a very low 10-year recurrence rate or RS. This is due to the heterogeneity of the biology of these cancers, regardless of their favorable or unfavorable histologic features.

In most cases, decisions about chemotherapy in patient who are postmenopausal, node-negative, and ER+ are made by risk estimates based on patient age, tumor grade, and tumor size, without knowledge of their RS. However, the large variability in 10-year rates of metastases and death among patients clearly demonstrates that, for some, chemotherapy affords no benefit. Their RS suggest that their risk of metastases at 10 years is only 2.8% when treated with EA (ie, tamoxifen) and no chemotherapy. In fact, 51% of the patients who are postmenopausal, node-negative, and ER+ in NSABP B-14 fell within the low risk RS category for 10-year distant recurrence, whereas about 27% fell within the high risk (RS > 31) category.¹³

Confidence in the Oncotype DX assay RS stems from the ability of investigators to plot the recurrence rates of distant metastases in patientstreated with tamoxifen vs placebo in the NSABP B-14 trial. Their clinicaloutcomes could be correlated with their GES samples retrieved from paraffin-embedded archival tissue many years after treatment. Corresponding plotting was done for similar patient cohorts treated with chemotherapy with or without tamoxifen in NSABP Trial B-20.

Among patients with low RS, the distant recurrence rate at 10 years was 2.2%, whether treated with systemic chemotherapy plus tamoxifenor with tamoxifen alone. Thus, in study participants with low RS, regardless of tumor size, grade, or patient age, 10-year recurrence rates were not affected by the addition of chemotherapy.¹³

Note that, in the absence of the new information provided by the Oncotype gene prognostic signature, nearly all these patients would be treated with systemic chemotherapy. Studies have shown that the additional risk assessment estimate provided by the Oncotype assay causes a change in systemic therapy recommendations from chemotherapy to no chemotherapy in 30% of patients.^14,15 Among patients with high RS, 10-year distant recurrence rates decreased by an absolute 27% with the addition of chemotherapy to tamoxifen. These patients clearly benefited from chemotherapy.¹³

The relative benefits of chemotherapy vs tamoxifen in a third RS group with an intermediate RS of 18-21 awaits publication of the now-closed Trial Assigning Individualized Options for Treatment (TAILORx) trial. This group accounts for 22% of patients who are postmenopausal, node-negative, and ER+ identified by the Oncotype DX assay. Initial reports show no significant benefit from the addition of chemotherapy to tamoxifen in this group.¹⁰

MammaPrint

Other gene prognostic signatures have recently been validated. Of these, the MammaPrint assay is the best established and validated.¹⁶ The MammaPrint uses a panel of 70 proliferation genes that were selected without bias by scanning the entire human genome. Unlike the Oncotype DX, the MammaPrint panel was randomly selected without any prior knowledge of the role of the proliferation genes in breast carcinogenesis. Furthermore, the reliability of the MammaPrint gene signature is independent of nodal status.¹⁷ This suggests that the intrinsic genetic makeup of the cancer establishes its biologic behavior and supersedes the impact of the traditional assessment of nodal involvement as a significant risk factor for distant metastases.

The MammaPrint GES was developed to identify patients at high risk of recurrence within 5 years of diagnosis; those for whom, as noted earlier, the salutary effect of chemotherapy is most evident.¹⁸ The assay is reliable for both pre- and postmenopausal women and stratifies patients into 2 risk groups only: high vs low.^19-21 The probability of remaining free of recurrent disease at 10 years is 85% in the low risk GES patients vs 50.6% in those with high risk MammaPrint prognosis signatures.¹⁷

Subsequent validation trials examined the accuracy of the MammaPrint as a prognostic indicator as well as a predictor of response to chemotherapy. These studies included node-negative, node-positive, pre- and postmenopausal women.^18-23 The risk of metastatic disease within the first 5 years after diagnosis was more significant in the high-risk than in the low-risk group. However, because the MammaPrint signature is independent of ER status, not all MammaPrint low-risk signatures are ER+. This reflects the contribution of unselected proliferation genes to the MammaPrint signature that results in the luminal A and luminal B breast cancer subtypes. In postmenopausal, node-negative patients, 61% may have good prognosis signatures, regardless of ER status.^18,22

A poor prognosis signature, then, would suggest the use of chemotherapy to prevent early (< 5 years from diagnosis) breast cancer deaths, but would still allow for EA to prevent late (> 5 years after diagnosis) recurrence for patients whose tumors were ER+. It should be noted that these findings also apply to patients treated with contemporary anthracycline chemotherapy regimens.²² The MammaPrint poor prognostic signature identifies patients at risk for early recurrence who may therefore benefit from chemotherapy, whereas the good prognostic signature identifies patients with a very low risk of distant metastases < 5 years.²² In the latter group, this low risk may not warrant use of systemic chemotherapy, but treatment with EA would confer a decrease in systemic metastases.

THE SURGEON’S PERSPECTIVE

To the surgeon, as suggested earlier, perhaps more pertinent is the available information on the use of chemotherapy before planned surgery for basal-type triple negative and HER-2+ breast cancers in the setting of luminal ER+ tumors. Mounting evidence suggests that the GES, such as those determined via the Oncotype and MammaPrint assays, can provide a very reliable indication of an individual patient’s response to PCT or chemotherapy in the neoadjuvant setting.^24,25 These clinical responses are easily quantitated on physical examination or by imaging in the few months during which a patient can receive PCT.

Furthermore, the absence of residual microscopic tumor in the breast and axilla (ie, pCR) after PCT can be predicted by the Oncotype DX RS and the MammaPrint GES. More than 11 reports (5,210 patients) have demonstrated a higher DFS and OS in patients who achieve a pCR after PCT.⁸ A pCR in a locally advanced patient with breast cancer can provide the surgeon with a margin-negative surgical procedure (BCS or mastectomy) and inform the patient of the potential for a much better DFS or OS than anticipated from the stage of breast cancer at presentation. 

In some patients amenable to BCS at presentation but whose tumor is too close to the chest wall or is proximate to a silicone augmentation prosthesis, the predicted response to systemic chemotherapy or hormonal ablation provided by GES can lead to a decrease in margin-positive rates and salvage of the previous cosmetic augmentation.

In patients at risk for carrying a BRCA mutation, the interval of PCT can be used for appropriate genetic testing and counseling and plastic surgery and gynecologic oncology consultations. Identified BRCA gene carriers may benefit from risk reduction surgery because of their increased breast and ovarian cancerrisk. Non-BRCA patients can consider BCS as an option, with decreased margin-positive rates and improved cosmesis. Information provided by GES can be essential to a good surgical outcome and underlines the need for preoperative consultation with medical oncology.²⁶

CONCLUSION

Gene expression signatures provide information about the biologic behavior of each individual patient’s breast cancer.  As new GES are introduced into clinical practice, surgeons must become fully informed about these advances in order to provide truly personalized cancer care plans to our patients.  

Author disclosures
The author reports no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the author and do not necessarily reflect an endorsement by or opinion of Federal Practitioner, Frontline Medical Communications, the U.S. Air Force, the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review complete prescribing information for specific drug combinations­–including indications, contraindications, warnings, and adverse effects–before administering pharmacologic therapy to patients.

The use of systemic chemotherapy and estrogen ablation (EA) for the treatment of breast cancer historically have been based on both the histologic prognostic parameters of the invasive breast cancer and on traditional estimates of recurrence risk. These estimates take into account the patient’s age, tumor size, grade, lymphovascular invasion, hormonal receptor status (estrogen receptor/progesterone receptor [ER/PR]), and human epidermal growth factor receptor 2 (HER2) overexpression.¹

The recent description of 4 primary breast cancer subtypes on the basis of gene expression profiles has led to the identification of more specific gene prognostic signatures.² These may serve to supplement, and possibly supersede, the assessment of recurrence risk currently employed as the basis for chemotherapy or EA recommendations for patients with breast cancer. As a result, many
patients who would have been treated with chemotherapy previously may now safely avoid it. The information provided by these prognostic signatures may also alter surgical decision making for many patients and, consequently, should be within the purview of dedicated cancer surgeons.

BREAST CANCER SUBTYPES

The 4 breast cancer subtypes are (1) the HER2 type, these can be ER/PR positive or negative; (2) basal-like tumors, typically ER, PR, and HER2 negative (ER-, PR-, and HER2-); and ER-positive (ER+) or luminal tumors, usually divided into (3) luminal A and (4) luminal B.²

HER2 Type

The advent of the first targeted breast cancer therapy, trastuzumab, and its immense salutary effect on survival of patients with previously poor prognoses has made the use of chemotherapy in combination with trastuzumab nearly mandatory in all HER2+ patients with breast cancer. Remarkably, the huge improvement in survival of these formerly doomed patients has led to the recommendation that trastuzumab-containing chemotherapy regimens should be used in the management of even subcentimeter, node-negative patients.³ This recommendation represents a clear change from the traditional recommendations for chemotherapy, which held that the benefits of systemic chemotherapy were more likely to be seen in patients with tumors in excess of 1 cm and/or who were node positive.

Basal-like Tumors

The discovery of trastuzumab made the basal-like tumor, which is usually ER-, PR-, and HER2- (triple negative), the subtype with the worst prognosis. Further, the natural course of this illness is markedly different from that of ER+/PR+ breast cancer. Nearly all basal-like or triple-negative patients with breast cancer who experience a recurrence do so within the first 5 years after diagnosis.⁴ In contrast, nearly 40% of ER+/PR+ HER2- breast cancer survivors experience their first recurrence beyond the 5-year milestone, with many even later in their course.⁵ Thus, the patient with triple-negative breast cancer is more likely to benefit from chemotherapy predominantly during the first 5 post-diagnosis years, as suggested by the Early Breast Cancer Trialists’ Collaborative Group meta-analyses.¹

HER2+ and triple-negative breast cancers account for 20% and 15% of all breast cancers, respectively.^6,7 In both subtypes, the benefit of chemotherapy is immense and chemotherapy will rarely be omitted from the treatment plan. Many of these patients are considered ideal candidates for preoperative chemotherapy (PCT), which results in increased rates of breast-conserving surgery (BCS), decreased positive margin rates at BCS, and decreased need for axillary node dissection. In the setting of PCT, a pathologic complete response (pCR) in the breast and axilla is increasingly recognized as a marker for improved disease-free survival (DFS) and overall survival (OS).⁸ For these reasons, preoperative consultation with medical oncologists is now even more important. Many of these patients will benefit from the use of PCT before any surgical treatment is undertaken.

Luminal Type (A and B)

The remaining two-thirds of all patients with breast cancer are ER+, primarily postmenopausal, and fall within the 2 remaining molecular subtypes: luminal A and luminal B. It is for these patients that the relative benefits of chemotherapy vs EA, or both, are currently being debated. For these patients the use of gene prognostic signatures, in concert with traditional histopathologic and clinical risk factors, may alter estimates of recurrence risk and the impact of chemotherapy on survival and recurrence estimates.

It is now evident that even the strongest predictors for breast cancer recurrence—histologic grade, patient age, and nodal status—are inconsistent predictors of the behavior of any individual tumor. While the use of chemotherapy can reduce the risk of metastases in these luminal-type patients with breast cancer, the majority of patients so stratified would survive without chemotherapy.⁹

GENE EXPRESSION SIGNATURE ASSAYS

One of the best demonstrations of the shortcomings of the standard risk predictors for ER+, HER2- breast cancers is provided by the Oncotype DX breast cancer assay’s recurrence score (RS) or gene expression signature (GES).^10,11

Oncotype DX

The Oncotype DX assay is the first commercially available GES assay to illustrate the variability in survival of patients with node-negative, ER+ breast tumors. Sixteen selected cancer proliferative genes are paired with 5 control nonproliferative genes whose relative activity can be measured in paraffin-embedded breast cancer tissue. The ability to retrieve reliable ribonucleic acid (RNA) expression from cancer cells embedded in paraffin was a stroke of genius; it enabled the investigators to correlate the gene expression profile of patient subgroups treated decades earlier with their long-term clinical outcomes and survival. 

The normalized summation of the proliferative activity of the 16 cancerproliferation genes in the Oncotype DX assay is expressed as the RS. The RS increases linearly and so does the average rate of distant recurrence in 10 years as a function of the RS. Three risk recurrence groups are defined by the RS: low risk (RS < 18); intermediate risk (RS > 18 to 30); and high risk (RS > 31).^10,11

Clinical Trials

In the National Surgical Adjuvant Breast and Bowel Project (NSABP) clinical trial B-14, ER+ node-negative patients were randomized to observation or tamoxifen. In the untreated control patients, a low RS (< 18) was accompanied by a 6.8% risk of metastasis at 10 years, and a high RS (> 31) was accompanied by a 30.5% rate of distant recurrence.¹¹ In another study, the low RS tamoxifen-treated arm showed a 2.8% risk of breast cancer death at 10 years vs a 15.5% risk in the high RS cohort.¹²

The remarkable significance of the RS is demonstrated when the RS is plotted against patient age, grade, or tumor size.¹⁰ This illustrates the huge variability in these traditional histopathologic and clinical features within a given RS group. For any patient with a low RS, there is marked variability in patient age, tumor grade, or tumor size. A very small or low-grade tumor can have a very high 10-year recurrence rate, as measured by the gene prognostic signature or RS. Similarly, a very large tumor in a young patient can have a very low 10-year recurrence rate or RS. This is due to the heterogeneity of the biology of these cancers, regardless of their favorable or unfavorable histologic features.

In most cases, decisions about chemotherapy in patient who are postmenopausal, node-negative, and ER+ are made by risk estimates based on patient age, tumor grade, and tumor size, without knowledge of their RS. However, the large variability in 10-year rates of metastases and death among patients clearly demonstrates that, for some, chemotherapy affords no benefit. Their RS suggest that their risk of metastases at 10 years is only 2.8% when treated with EA (ie, tamoxifen) and no chemotherapy. In fact, 51% of the patients who are postmenopausal, node-negative, and ER+ in NSABP B-14 fell within the low risk RS category for 10-year distant recurrence, whereas about 27% fell within the high risk (RS > 31) category.¹³

Confidence in the Oncotype DX assay RS stems from the ability of investigators to plot the recurrence rates of distant metastases in patientstreated with tamoxifen vs placebo in the NSABP B-14 trial. Their clinicaloutcomes could be correlated with their GES samples retrieved from paraffin-embedded archival tissue many years after treatment. Corresponding plotting was done for similar patient cohorts treated with chemotherapy with or without tamoxifen in NSABP Trial B-20.

Among patients with low RS, the distant recurrence rate at 10 years was 2.2%, whether treated with systemic chemotherapy plus tamoxifenor with tamoxifen alone. Thus, in study participants with low RS, regardless of tumor size, grade, or patient age, 10-year recurrence rates were not affected by the addition of chemotherapy.¹³

Note that, in the absence of the new information provided by the Oncotype gene prognostic signature, nearly all these patients would be treated with systemic chemotherapy. Studies have shown that the additional risk assessment estimate provided by the Oncotype assay causes a change in systemic therapy recommendations from chemotherapy to no chemotherapy in 30% of patients.^14,15 Among patients with high RS, 10-year distant recurrence rates decreased by an absolute 27% with the addition of chemotherapy to tamoxifen. These patients clearly benefited from chemotherapy.¹³

The relative benefits of chemotherapy vs tamoxifen in a third RS group with an intermediate RS of 18-21 awaits publication of the now-closed Trial Assigning Individualized Options for Treatment (TAILORx) trial. This group accounts for 22% of patients who are postmenopausal, node-negative, and ER+ identified by the Oncotype DX assay. Initial reports show no significant benefit from the addition of chemotherapy to tamoxifen in this group.¹⁰

MammaPrint

Other gene prognostic signatures have recently been validated. Of these, the MammaPrint assay is the best established and validated.¹⁶ The MammaPrint uses a panel of 70 proliferation genes that were selected without bias by scanning the entire human genome. Unlike the Oncotype DX, the MammaPrint panel was randomly selected without any prior knowledge of the role of the proliferation genes in breast carcinogenesis. Furthermore, the reliability of the MammaPrint gene signature is independent of nodal status.¹⁷ This suggests that the intrinsic genetic makeup of the cancer establishes its biologic behavior and supersedes the impact of the traditional assessment of nodal involvement as a significant risk factor for distant metastases.

The MammaPrint GES was developed to identify patients at high risk of recurrence within 5 years of diagnosis; those for whom, as noted earlier, the salutary effect of chemotherapy is most evident.¹⁸ The assay is reliable for both pre- and postmenopausal women and stratifies patients into 2 risk groups only: high vs low.^19-21 The probability of remaining free of recurrent disease at 10 years is 85% in the low risk GES patients vs 50.6% in those with high risk MammaPrint prognosis signatures.¹⁷

Subsequent validation trials examined the accuracy of the MammaPrint as a prognostic indicator as well as a predictor of response to chemotherapy. These studies included node-negative, node-positive, pre- and postmenopausal women.^18-23 The risk of metastatic disease within the first 5 years after diagnosis was more significant in the high-risk than in the low-risk group. However, because the MammaPrint signature is independent of ER status, not all MammaPrint low-risk signatures are ER+. This reflects the contribution of unselected proliferation genes to the MammaPrint signature that results in the luminal A and luminal B breast cancer subtypes. In postmenopausal, node-negative patients, 61% may have good prognosis signatures, regardless of ER status.^18,22

A poor prognosis signature, then, would suggest the use of chemotherapy to prevent early (< 5 years from diagnosis) breast cancer deaths, but would still allow for EA to prevent late (> 5 years after diagnosis) recurrence for patients whose tumors were ER+. It should be noted that these findings also apply to patients treated with contemporary anthracycline chemotherapy regimens.²² The MammaPrint poor prognostic signature identifies patients at risk for early recurrence who may therefore benefit from chemotherapy, whereas the good prognostic signature identifies patients with a very low risk of distant metastases < 5 years.²² In the latter group, this low risk may not warrant use of systemic chemotherapy, but treatment with EA would confer a decrease in systemic metastases.

THE SURGEON’S PERSPECTIVE

To the surgeon, as suggested earlier, perhaps more pertinent is the available information on the use of chemotherapy before planned surgery for basal-type triple negative and HER-2+ breast cancers in the setting of luminal ER+ tumors. Mounting evidence suggests that the GES, such as those determined via the Oncotype and MammaPrint assays, can provide a very reliable indication of an individual patient’s response to PCT or chemotherapy in the neoadjuvant setting.^24,25 These clinical responses are easily quantitated on physical examination or by imaging in the few months during which a patient can receive PCT.

Furthermore, the absence of residual microscopic tumor in the breast and axilla (ie, pCR) after PCT can be predicted by the Oncotype DX RS and the MammaPrint GES. More than 11 reports (5,210 patients) have demonstrated a higher DFS and OS in patients who achieve a pCR after PCT.⁸ A pCR in a locally advanced patient with breast cancer can provide the surgeon with a margin-negative surgical procedure (BCS or mastectomy) and inform the patient of the potential for a much better DFS or OS than anticipated from the stage of breast cancer at presentation. 

In some patients amenable to BCS at presentation but whose tumor is too close to the chest wall or is proximate to a silicone augmentation prosthesis, the predicted response to systemic chemotherapy or hormonal ablation provided by GES can lead to a decrease in margin-positive rates and salvage of the previous cosmetic augmentation.

In patients at risk for carrying a BRCA mutation, the interval of PCT can be used for appropriate genetic testing and counseling and plastic surgery and gynecologic oncology consultations. Identified BRCA gene carriers may benefit from risk reduction surgery because of their increased breast and ovarian cancerrisk. Non-BRCA patients can consider BCS as an option, with decreased margin-positive rates and improved cosmesis. Information provided by GES can be essential to a good surgical outcome and underlines the need for preoperative consultation with medical oncology.²⁶

CONCLUSION

Gene expression signatures provide information about the biologic behavior of each individual patient’s breast cancer.  As new GES are introduced into clinical practice, surgeons must become fully informed about these advances in order to provide truly personalized cancer care plans to our patients.  

Author disclosures
The author reports no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the author and do not necessarily reflect an endorsement by or opinion of Federal Practitioner, Frontline Medical Communications, the U.S. Air Force, the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review complete prescribing information for specific drug combinations­–including indications, contraindications, warnings, and adverse effects–before administering pharmacologic therapy to patients.

Cells grown on hydrogels

Adam Engler, UC San Diego

Jacobs School of Engineering

The stiffness of the extracellular matrix may play a larger role in stem cell differentiation than we thought, according to a new study.

Scientists have recently suggested that protein tethering and matrix porosity, as well as matrix stiffness and ligand type, regulate stem cell differentiation.

However, new research published in Nature Materials indicates that matrix stiffness regulates stem cell differentiation independently of tethering and porosity.

Adam Engler, PhD, of the University of California, San Diego, and his colleagues discovered that human adipose stromal cells and mesenchymal stromal cells underwent osteogenic differentiation if placed in a stiff hydrogel. But the cells underwent adipogenesis if placed in a soft hydrogel.

The protein binding the stem cell to the hydrogel was not a factor in the differentiation process. Results suggested the protein layer was merely an adhesive.

The researchers found that stem cell differentiation is a response to the mechanical deformation of the hydrogel from the force exerted by the cell. With a series of experiments, the team showed that this happens whether the protein tethering the cell to the matrix is tight, loose, or nonexistent.

Across multiple samples using a stiff matrix, varying the degree of tethering made no significant difference in the rate of osteogenic or adipogenic differentiation.

Likewise, the size of the pores in the matrix had no effect on stem cell differentiation, as long as the stiffness of the hydrogel remained the same.

However, Dr Engler pointed out that matrix stiffness is only “one cue out of dozens that are important in stem cell differentiation.”

“That doesn’t mean the other cues are irrelevant,” he noted. “They may still push the cells into a specific cell type. We have just ruled out porosity and tethering, and further emphasized stiffness in this process.”

Cells grown on hydrogels

Adam Engler, UC San Diego

Jacobs School of Engineering

The stiffness of the extracellular matrix may play a larger role in stem cell differentiation than we thought, according to a new study.

Scientists have recently suggested that protein tethering and matrix porosity, as well as matrix stiffness and ligand type, regulate stem cell differentiation.

However, new research published in Nature Materials indicates that matrix stiffness regulates stem cell differentiation independently of tethering and porosity.

Adam Engler, PhD, of the University of California, San Diego, and his colleagues discovered that human adipose stromal cells and mesenchymal stromal cells underwent osteogenic differentiation if placed in a stiff hydrogel. But the cells underwent adipogenesis if placed in a soft hydrogel.

The protein binding the stem cell to the hydrogel was not a factor in the differentiation process. Results suggested the protein layer was merely an adhesive.

The researchers found that stem cell differentiation is a response to the mechanical deformation of the hydrogel from the force exerted by the cell. With a series of experiments, the team showed that this happens whether the protein tethering the cell to the matrix is tight, loose, or nonexistent.

Across multiple samples using a stiff matrix, varying the degree of tethering made no significant difference in the rate of osteogenic or adipogenic differentiation.

Likewise, the size of the pores in the matrix had no effect on stem cell differentiation, as long as the stiffness of the hydrogel remained the same.

However, Dr Engler pointed out that matrix stiffness is only “one cue out of dozens that are important in stem cell differentiation.”

“That doesn’t mean the other cues are irrelevant,” he noted. “They may still push the cells into a specific cell type. We have just ruled out porosity and tethering, and further emphasized stiffness in this process.”

Cells grown on hydrogels

Adam Engler, UC San Diego

Jacobs School of Engineering

The stiffness of the extracellular matrix may play a larger role in stem cell differentiation than we thought, according to a new study.

Scientists have recently suggested that protein tethering and matrix porosity, as well as matrix stiffness and ligand type, regulate stem cell differentiation.

However, new research published in Nature Materials indicates that matrix stiffness regulates stem cell differentiation independently of tethering and porosity.

Adam Engler, PhD, of the University of California, San Diego, and his colleagues discovered that human adipose stromal cells and mesenchymal stromal cells underwent osteogenic differentiation if placed in a stiff hydrogel. But the cells underwent adipogenesis if placed in a soft hydrogel.

The protein binding the stem cell to the hydrogel was not a factor in the differentiation process. Results suggested the protein layer was merely an adhesive.

The researchers found that stem cell differentiation is a response to the mechanical deformation of the hydrogel from the force exerted by the cell. With a series of experiments, the team showed that this happens whether the protein tethering the cell to the matrix is tight, loose, or nonexistent.

Across multiple samples using a stiff matrix, varying the degree of tethering made no significant difference in the rate of osteogenic or adipogenic differentiation.

Likewise, the size of the pores in the matrix had no effect on stem cell differentiation, as long as the stiffness of the hydrogel remained the same.

However, Dr Engler pointed out that matrix stiffness is only “one cue out of dozens that are important in stem cell differentiation.”

“That doesn’t mean the other cues are irrelevant,” he noted. “They may still push the cells into a specific cell type. We have just ruled out porosity and tethering, and further emphasized stiffness in this process.”

This article has been adapted from an article originally published in The Journal of Supportive and Community Oncology (jcso-online.com). Schindler K, Postow M. Current options and future directions in the systemic treatment of metastatic melanoma. J Community Support Oncol. 2014;12(1):20-26. 

The incidence of melanoma, a highly aggressive tumor arising from melanocytes, continues to rise by about 3% a year in the U.S. with about 76,000 patients being diagnosed every year and 9,000 patients dying of the disease.¹ Complete surgical resection is the standard for localized melanoma, with surgical excision margins depending on tumor thickness. For patients with involved sentinel lymph nodes, complete lymphadenectomy is typically recommended, although the benefits of completion lymphadenectomy are being evaluated in an ongoing randomized trial.^2,3

For patients with surgically resected, high-risk melanoma, the only approved adjuvant therapy is interferon-a (IFN-a).⁴ Use of IFN-a, however, remains controversial because of the associated adverse effects (AEs) and controversial effects on overall survival (OS).^5,6 Unfortunately, many patients with localized disease will ultimately experience a recurrence, and the prognosis of patients with metastatic disease is poor with a historical 5-year survival rate of 10%.⁷

Chemotherapy and interleukin 2

For more than 3 decades, conventional cytotoxic chemotherapy was used to treat metastatic melanoma. Typical agents included alkylating agents (dacarbazine, temozolomide, nitrosoureas), platinum analogs (cisplatin and carboplatin), and microtubular toxins (vinblastine and paclitaxel). Despite the clinical use and investigation of a number of these chemotherapies for patients with metastatic melanoma, the only treatment approved by the FDA is dacarbazine, which is administered intravenously every 3 to 4 weeks at a dose of 800 to 1,000 mg/m².

Monotherapy with dacarbazine is generally well tolerated with only mild AEs such as nausea, myelosuppression, and fatigue. In a pooled analysis, the overall response rate (RR) for dacarbazine was approximately 9%.⁸ Temozolomide, the oral analog of dacarbazine, penetrates into the central nervous system and has been compared with dacarbazine in randomized trials. These agents are believed to have similar efficacy, but temozolomide has been associated with a higher rate of lymphopenia.^9,10

Investigation of chemotherapy combinations such as cisplatin, vinblastine, and dacarbazine or carboplatin and paclitaxel have shown promising RRs but unfortunately no prolongation of OS compared with single-agent dacarbazine.^11-13 Despite its modest efficacy, chemotherapy still has a place in the palliative treatment for some patients.

In addition to dacarbazine, the immunotherapeutic strategy, high-dose recombinant interleukin-2 (IL-2), had also been a mainstay treatment for advanced melanoma for many years. IL-2 is administered as an IV infusion every 8 hours at a dose of 600,000 to 720,000  IU/kg on days 1 to 5 and days 15 to 19, with a maximum of 14 such biphasic cycles. Because of the significant acute toxicity profile, including capillary leak syndrome, cardiovascular complications, and seizures, IL-2 treatment requires hospitalization and is generally only performed at specialized centers for patients with good performance status. Though the overall RR in pooled analysis was low at 16%, the durability of responses in some responders that appeared to last many years led to the FDA approval of IL-2 in 1998.^14,15

IL-2 continues to be investigated. In a randomized trial, an improved RR and progression-free survival (PFS) were seen when IL-2 was combined with the glycoprotein 100 (gp100) peptide vaccine compared with IL-2 alone.¹⁶ Other approaches have sought to improve the safety of IL-2 by selectively delivering it to tumor sites. The fusion protein L19-IL2 couples IL-2 with the recombinant human vascular targeting antibody L19 and has preliminarily been shown to be safe in phase 1 evaluation and in combination with dacarbazine.^17,18

Antibodies that block immunologic checkpoints

Melanoma has long been recognized as an immunogenic malignancy but the efficacy of immunotherapeutic strategies has generally been modest. The precise etiology of why immunotherapy historically was not more successful is not completely understood, but it is possible that patients with advanced malignancy have predominant immune inhibitory circuits that prevent otherwise effective antitumor immune responses.

In recent years, research has illuminated some of these immunologic inhibitory elements, termed “immunologic checkpoints,” which include cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1). Antibodies that target these checkpoints have resulted in durable responses in some patients and a unique pattern of immune-mediated AEs. Though an ongoing area of research, no pre- or on-treatment biomarkers have been sufficiently validated to enable specific patient selection for these therapies.

Antibodies Blocking CTLA-4

CTLA-4 is expressed on activated T cells and typically functions as a negative regulator of T-cell activity preserving normal immunologic homeostasis. Blocking CTLA-4 with therapeutic antibodies such as ipilimumab and tremelimumab prevents normal CTLA-4–mediated T-cell downregulation and thereby enhances the ability of T cells to exert their full antitumor immune effects (Figure 1). Ipilimumab was the first drug in the management of metastatic melanoma to show an improvement in OS in phase 3 studies, and although a phase 3 study of tremelimumab did not demonstrate an improvement in OS, durable responses were similarly seen.^19-21

The first phase 3 trial investigating ipilimumab randomized previously pretreated patients with advanced melanoma to ipilimumab at a dose of 3 mg/kg with or without the gp100 peptide vaccine. The median OS was 10.0 months among patients receiving ipilimumab plus gp100, compared with 6.4 months among patients receiving gp100 alone. There was no difference in OS between the ipilimumab groups.¹⁹ The outcome of this study has led to the approval of ipilimumab at a dose of 3 mg/kg in patients with advanced melanoma by regulatory agencies in the U.S., European Union, and Australia.

For treatment-naive patients, a second phase 3 trial investigating dacarbazine in combination with ipilimumab compared with dacarbazine in combination with placebo also demonstrated improvement of OS in patients treated with dacarbazine in combination with ipilimumab.²⁰ The estimated 1-year, 2-year, and 3-year survival rates were 47.3%, 28.5%, and 20.8%, respectively, in the dacarbazine plus ipilimumab group, compared with 36.3%, 17.9%, and 12.2% in the dacarbazine alone group. This second trial used a higher dose of ipilimumab (10 mg/kg) and though it confirmed ipilimumab’s beneficial effects on OS, ipilimumab is not approved at 10 mg/kg and is not routinely recommended to be used in combination with dacarbazine given hepatic toxicity concerns.

Though the median OS was improved in these phase 3 trials, perhaps the greatest activity of ipilimumab lies in the increased number of patients who can achieve long-term OS. In a recently published updated survival analysis, the 4-year survival rates for previously treated patients who received ipilimumab at 3 or 10 mg/kg were 18.2% and 19.7% to 28.4%. For treatment-naive patients receiving ipilimumab at 10 mg/kg, 4-year survival rates were between 37.7% and 49.5%.²² These values appear superior to historical data from prior chemotherapy trials.

An important consideration in the clinical use of CTLA-4 blocking antibodies is the possible occurrence of toxicities that differ from those associated with traditional chemotherapy. These AEs are termed immune-related AEs (irAEs), and they most commonly manifest as diarrhea, dermatitis, hepatitis, and endocrinopathies but less commonly can involve other organs, resulting in uveitis, nephritis, myopathy, and neuropathy.

In general, the onset of irAEs follows a certain pattern with cutaneous manifestations often presenting early in treatment, followed by gastrointestinal and hepatic events occurring about 2 months into therapy and endocrinopathies appearing even later.²³ In rare cases, severe AEs (eg, perforating colitis, toxic epidermal necrolysis) can occur and may require hospitalization.²⁴

Clinicians must be attentive to early signs of these AEs and promptly initiate immunosuppression with steroids or other immunosuppressive medications, which do not appear to diminish the antitumor immune effects.²⁵ Established management algorithms exist to guide clinicians. Given the occasional need for immunosuppression in this patient population, awareness of the possibility of opportunistic or rare infections is also important.

In phase 3 evaluation, the number of patients who had long-term survival exceeded the number of patients who had a classically defined disease response to treatment. Durable stable disease and late responses have been observed clinically and may be responsible for some of the beneficial outcomes.²⁶ If patients are asymptomatic and have minimal radiographic progression, it is reasonable to repeat imaging 1 to 2 months later to confirm progression before considering additional lines of therapy.

Antibodies Blocking the Programmed Death-1 Axis

Programmed death-1 (PD-1) is a receptor on the surface of T cells that is upregulated at later stages of T-cell activation as opposed to the early upregulation of CTLA-4. Normally, engagement of PD-1 attenuates T-cell activity at several phases of an immune response. Tumors are believed to escape immune attack by similarly inhibiting T-cell activity by upregulating one of the ligands of PD-1, PD-L1.^27,28 Several antibodies that inhibit PD-1 activity, either by blocking the PD-1 molecule itself or PD-L1, are demonstrating significant promise in ongoing clinical trials.

Nivolumab (previously, BMS-936558) is a fully human monoclonal antibody targeting PD-1. In a large phase 1 study in patients with a variety of malignancies, nivolumab demonstrated a 31% RR in patients with advanced melanoma.²⁹ Subsequent follow-up data indicates these responses are generally durable with a median duration of response of 24 months and a 3-year OS rate of 40%.³⁰ Adverse effects of nivolumab appear less frequently than with CTLA-4 blockade but have included vitiligo, colitis, hepatitis, hypophysitis, and thyroiditis. Unique to PD-1 blockade appears to be the AE of an inflammatory pneumonitis, which can present with a dry cough, dyspnea, and ground-glass opacities and can be potentially lethal.²⁹

On the basis of complementary regulatory roles of CTLA-4 and PD-1 checkpoint inhibition, a trial investigating combined nivolumab and ipilimumab was completed. In the small group of patients treated, a high RR was seen with a generally acceptable safety profile.³¹ Ongoing phase 2 and 3 trials are assessing nivolumab alone and in combination with other agents for the treatment of advanced melanoma and other malignancies (Table 1).

Another PD-1 blocking antibody, MK-3475, has been evaluated in patients with advanced melanoma, and promising RRs have been described.³² In a small group of patients, the confirmed RR at a dose of 10 mg/kg every 2 weeks was 52% and appeared similar in patients who had and who had not been previously treated with ipilimumab. The AEs of MK-3475 seem to resemble nivolumab. MK-3475 is similarly being evaluated in large phase 2 and 3 trials for both patients with melanoma and additional malignancies.

In addition to antibodies targeting PD-1, clinical activity has also been observed with several different antibodies (BMS-936559, MPDL3280A, and MEDI4736) that target PD-L1. Though some data have been published for this therapeutic strategy,³³ ongoing trials will continue to clarify the role of targeting PD-L1 in patients with advanced melanoma.

Targeted Therapies That Block Oncogenic Signaling Pathways

The mitogen-activated protein kinase (MAPK) pathway responds to extracellular growth signals and regulates cell proliferation and survival. In many patients with melanoma, the MAPK pathway is constitutively activated as a result of molecular alterations in genes encoding key regulators or components of the pathway such as BRAF, NRAS, and KIT.^34,35 The most common mutation arising in melanoma is the BRAF mutation, occurring in nearly half of melanomas, and typically involves a missense mutation in which glutamic acid is substituted for valine at codon 600 (BRAF V600E mutation).³⁶ Less frequent BRAF mutations include V600K, V600R, and K601E.³⁷ Strategies that directly inhibit oncogenic BRAF or disable downstream elements such as MEK have recently shown dramatic results in patients with melanoma (Figure 2).

BRAF inhibitors

Vemurafenib is a potent inhibitor of mutated BRAF with marked antitumor effects against melanoma cell lines with the BRAF V600E mutation.³⁸ The first striking results of tumor regression with this strategy in patients were seen in a phase 1 study in patients with melanoma characterized by a BRAF V600E mutation but not in patients whose melanomas did not have a BRAF mutation.³⁹

Subsequent phase 3 trials confirmed the high RRs of this agent in patients with BRAF-mutant melanoma and demonstrated superiority in OS compared with dacarbazine chemotherapy.⁴⁰ The results of this phase 3 trial led to the approval of vemurafenib by the FDA in August 2011 with treatment exclusively limited to patients with BRAF mutant melanoma. Updated OS data from this phase 3 study revealed a median OS of 13.2 months for vemurafenib, compared with 9.6 months for dacarbazine, with an overall RR in patients treated with vemurafenib of 57% and a median PFS of 6.9 months.⁴¹ General AEs with vemurafenib include arthralgia, fatigue, aminotransferase elevations, nausea and vomiting, and decreased kidney function. In general, toxicities are manageable with dose reduction or temporary drug cessation.

One characteristic of vemurafenib and other BRAF-targeted agents is the frequent development of hyperproliferative skin AEs. Skin lesions, including follicular and palmo-plantar hyperkeratosis, papillomas, and also cutaneous squamous-cell carcinomas and keratoacanthomas, have commonly been observed under treatment with vemurafenib, and close evaluation by a dermatologist is important.⁴² The mechanism of this phenomenon is believed to be a paradoxical activation of the MAPK pathway in nonmelanoma BRAF wild-type cells when systemic treatment with a BRAF inhibitor is administered.⁴³

The phenomenon of hyperproliferation of non–BRAF-mutant tissues with ongoing BRAF-inhibitor therapy has also been seen in patients with lymphoproliferative disorders and may be a mechanism involved in the discovery that patients have a high rate of new primary melanomas while on therapy.^44,45 These findings warrant special attention, particularly as BRAF inhibitors are undergoing evaluation as adjuvant therapy.

Another active BRAF kinase inhibitor with a similar efficacy profile as vemurafenib is dabrafenib, which was approved in May 2013 based on the demonstration of improved PFS in a phase 3 trial comparing dabrafenib 150 mg orally twice daily and dacarbazine 1,000 mg/m² intravenously once every 3 weeks in previously untreated patients with BRAF V600E mutant melanoma. The median PFS times were 5.1 and 2.7 months in the dabrafenib and dacarbazine arms, respectively, with an objective RR of 52% in patients treated with dabrafenib.⁴⁶ Follow-up time was too short to make a determination of the impact of dabrafenib on OS. In a separate study, dabrafenib was also shown to be effective for patients with brain metastases and remains an excellent therapeutic choice for this particular patient population.⁴⁷

Generally, dabrafenib is believed to have similar efficacy to vemurafenib. Nevertheless, EAs with of dabrafenib differ somewhat from those observed with vemurafenib: The rate of proliferative skin lesions, including squamous cell carcinomas and keratoacanthomas appears to be lower for dabrafenib than vemurafenib. However, AEs particular to dabrafenib have been seen such as pyrexia, which were recorded in about 11% of patients.⁴⁶

MEK inhibitors

Though targeting oncogenic BRAF directly has been incredibly successful for patients with BRAF-mutant metastatic melanoma, additional success has been observed by blocking the MAPK pathway at a downstream component, MEK. Trametinib is an MEK inhibitor that was approved by the FDA in June 2013 as a single agent for patients with BRAF V600E or V600K mutant melanoma. Trametinib is administered at a dose of 2 mg once daily and was shown to improve PFS and OS compared with dacarbazine and paclitaxel chemotherapies.⁴⁷ Despite the improvement in PFS and OS compared with chemotherapy, the objective RR for trametinib was somewhat lower (22%) than that seen with BRAF inhibitors.

Trametinib also is associated with a different AE profile from BRAF inhibitors and includes diarrhea, peripheral edema, hypertension, and fatigue, typical of other MEK inhibitors as well.⁴⁸ Asymptomatic and reversible reduction of the cardiac ejection fraction and ocular toxic effects also occur infrequently. Unlike with BRAF-inhibitor treatment, the development of cutaneous squamous-cell carcinomas or other hyperproliferative skin lesions was not noted.⁴⁹

Despite the significant benefits of targeted therapy disrupting overly active MAPK signaling in patients with BRAF-mutant metastatic melanoma, almost all patients treated with these targeted inhibitors who achieve an initial response will ultimately progress. Several mechanisms of resistance have been proposed, and most relate to reactivation of the MAPK pathway.^50,51 As a result, efforts to maintain suppression of the MAPK pathway have been pursued to delay the onset of resistance. In a phase 2 trial that combined dabrafenib with trametinib, there was a longer PFS than there was with dabrafenib monotherapy.⁵²

Furthermore, the addition of trametinib to dabrafenib reduced the incidence of squamous-cell carcinoma, providing further evidence that reactivation of the MAPK pathway is involved in these hyperproliferative skin lesions arising under BRAF-directed therapy. A higher rate of febrile episodes was seen, however. An ongoing phase 3 study is looking at whether or not combining BRAF and MEK inhibitors results in improved OS compared with single-agent BRAF. It is premature at this juncture to recommend combining dabrafenib and trametinib until the results of the ongoing phase 3 studies more thoroughly describe the risks and benefits of this approach (Table 2).

KIT inhibitors

In a subset of melanomas, particularly those that arise from mucosal, acral, or chronically sun-damaged skin, mutations are found in the receptor-tyrosine kinase KIT.³⁵ A number of agents directed against KIT, such as imatinib, have been tested in clinical trials. Initial phase 2 studies revealed poor RRs with KIT inhibition in molecularly unselected patients.^53-55 Subsequent studies selected patients with KIT genetic aberrations, including mutations and amplifications, and some responses were seen.^56-58

Importantly, not all KIT genetic aberrations are believed to be considered equal. Preliminarily, it appears that mutations in exon 11 (L576P) and exon 13 (K642E) appear to be most closely associated with response and may be true driver mutations. Other KIT mutations may have less functional significance but additional research is needed. Imatinib is a reasonable therapeutic choice in patients with a KIT mutation, particularly when an L576P or K642E mutation is present.

conclusions

Since 2011, 4 new drugs—ipilimumab, vemurafenib, dabrafenib, and trametinib—have been approved for the treatment of metastatic melanoma. Exciting early data from PD-1 clinical trials suggest that agents that disrupt PD-1 may also become important therapeutic modalities. Future studies will continue to evaluate combinations of these therapeutic modalities, but caution should be exercised in combining these drugs prior to data from ongoing clinical trials revealing the true benefits and risks of combination therapy. Excessive toxicity was seen in an early phase trial when vemurafenib was combined with ipilimumab.⁵⁹

Additional research will also explore biomarkers that may help clinicians apply immunotherapy to the most appropriate patients and better understand mechanisms of resistance to targeted therapies. Clinical trials of novel agents or combinations should be considered at every treatment juncture to continue the rapid pace of developing the most innovative and tailored treatment approaches.  

Author disclosures
The authors report no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.

This article has been adapted from an article originally published in The Journal of Supportive and Community Oncology (jcso-online.com). Schindler K, Postow M. Current options and future directions in the systemic treatment of metastatic melanoma. J Community Support Oncol. 2014;12(1):20-26. 

The incidence of melanoma, a highly aggressive tumor arising from melanocytes, continues to rise by about 3% a year in the U.S. with about 76,000 patients being diagnosed every year and 9,000 patients dying of the disease.¹ Complete surgical resection is the standard for localized melanoma, with surgical excision margins depending on tumor thickness. For patients with involved sentinel lymph nodes, complete lymphadenectomy is typically recommended, although the benefits of completion lymphadenectomy are being evaluated in an ongoing randomized trial.^2,3

For patients with surgically resected, high-risk melanoma, the only approved adjuvant therapy is interferon-a (IFN-a).⁴ Use of IFN-a, however, remains controversial because of the associated adverse effects (AEs) and controversial effects on overall survival (OS).^5,6 Unfortunately, many patients with localized disease will ultimately experience a recurrence, and the prognosis of patients with metastatic disease is poor with a historical 5-year survival rate of 10%.⁷

Chemotherapy and interleukin 2

For more than 3 decades, conventional cytotoxic chemotherapy was used to treat metastatic melanoma. Typical agents included alkylating agents (dacarbazine, temozolomide, nitrosoureas), platinum analogs (cisplatin and carboplatin), and microtubular toxins (vinblastine and paclitaxel). Despite the clinical use and investigation of a number of these chemotherapies for patients with metastatic melanoma, the only treatment approved by the FDA is dacarbazine, which is administered intravenously every 3 to 4 weeks at a dose of 800 to 1,000 mg/m².

Monotherapy with dacarbazine is generally well tolerated with only mild AEs such as nausea, myelosuppression, and fatigue. In a pooled analysis, the overall response rate (RR) for dacarbazine was approximately 9%.⁸ Temozolomide, the oral analog of dacarbazine, penetrates into the central nervous system and has been compared with dacarbazine in randomized trials. These agents are believed to have similar efficacy, but temozolomide has been associated with a higher rate of lymphopenia.^9,10

Investigation of chemotherapy combinations such as cisplatin, vinblastine, and dacarbazine or carboplatin and paclitaxel have shown promising RRs but unfortunately no prolongation of OS compared with single-agent dacarbazine.^11-13 Despite its modest efficacy, chemotherapy still has a place in the palliative treatment for some patients.

In addition to dacarbazine, the immunotherapeutic strategy, high-dose recombinant interleukin-2 (IL-2), had also been a mainstay treatment for advanced melanoma for many years. IL-2 is administered as an IV infusion every 8 hours at a dose of 600,000 to 720,000  IU/kg on days 1 to 5 and days 15 to 19, with a maximum of 14 such biphasic cycles. Because of the significant acute toxicity profile, including capillary leak syndrome, cardiovascular complications, and seizures, IL-2 treatment requires hospitalization and is generally only performed at specialized centers for patients with good performance status. Though the overall RR in pooled analysis was low at 16%, the durability of responses in some responders that appeared to last many years led to the FDA approval of IL-2 in 1998.^14,15

IL-2 continues to be investigated. In a randomized trial, an improved RR and progression-free survival (PFS) were seen when IL-2 was combined with the glycoprotein 100 (gp100) peptide vaccine compared with IL-2 alone.¹⁶ Other approaches have sought to improve the safety of IL-2 by selectively delivering it to tumor sites. The fusion protein L19-IL2 couples IL-2 with the recombinant human vascular targeting antibody L19 and has preliminarily been shown to be safe in phase 1 evaluation and in combination with dacarbazine.^17,18

Antibodies that block immunologic checkpoints

Melanoma has long been recognized as an immunogenic malignancy but the efficacy of immunotherapeutic strategies has generally been modest. The precise etiology of why immunotherapy historically was not more successful is not completely understood, but it is possible that patients with advanced malignancy have predominant immune inhibitory circuits that prevent otherwise effective antitumor immune responses.

In recent years, research has illuminated some of these immunologic inhibitory elements, termed “immunologic checkpoints,” which include cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1). Antibodies that target these checkpoints have resulted in durable responses in some patients and a unique pattern of immune-mediated AEs. Though an ongoing area of research, no pre- or on-treatment biomarkers have been sufficiently validated to enable specific patient selection for these therapies.

Antibodies Blocking CTLA-4

CTLA-4 is expressed on activated T cells and typically functions as a negative regulator of T-cell activity preserving normal immunologic homeostasis. Blocking CTLA-4 with therapeutic antibodies such as ipilimumab and tremelimumab prevents normal CTLA-4–mediated T-cell downregulation and thereby enhances the ability of T cells to exert their full antitumor immune effects (Figure 1). Ipilimumab was the first drug in the management of metastatic melanoma to show an improvement in OS in phase 3 studies, and although a phase 3 study of tremelimumab did not demonstrate an improvement in OS, durable responses were similarly seen.^19-21

The first phase 3 trial investigating ipilimumab randomized previously pretreated patients with advanced melanoma to ipilimumab at a dose of 3 mg/kg with or without the gp100 peptide vaccine. The median OS was 10.0 months among patients receiving ipilimumab plus gp100, compared with 6.4 months among patients receiving gp100 alone. There was no difference in OS between the ipilimumab groups.¹⁹ The outcome of this study has led to the approval of ipilimumab at a dose of 3 mg/kg in patients with advanced melanoma by regulatory agencies in the U.S., European Union, and Australia.

For treatment-naive patients, a second phase 3 trial investigating dacarbazine in combination with ipilimumab compared with dacarbazine in combination with placebo also demonstrated improvement of OS in patients treated with dacarbazine in combination with ipilimumab.²⁰ The estimated 1-year, 2-year, and 3-year survival rates were 47.3%, 28.5%, and 20.8%, respectively, in the dacarbazine plus ipilimumab group, compared with 36.3%, 17.9%, and 12.2% in the dacarbazine alone group. This second trial used a higher dose of ipilimumab (10 mg/kg) and though it confirmed ipilimumab’s beneficial effects on OS, ipilimumab is not approved at 10 mg/kg and is not routinely recommended to be used in combination with dacarbazine given hepatic toxicity concerns.

Though the median OS was improved in these phase 3 trials, perhaps the greatest activity of ipilimumab lies in the increased number of patients who can achieve long-term OS. In a recently published updated survival analysis, the 4-year survival rates for previously treated patients who received ipilimumab at 3 or 10 mg/kg were 18.2% and 19.7% to 28.4%. For treatment-naive patients receiving ipilimumab at 10 mg/kg, 4-year survival rates were between 37.7% and 49.5%.²² These values appear superior to historical data from prior chemotherapy trials.

An important consideration in the clinical use of CTLA-4 blocking antibodies is the possible occurrence of toxicities that differ from those associated with traditional chemotherapy. These AEs are termed immune-related AEs (irAEs), and they most commonly manifest as diarrhea, dermatitis, hepatitis, and endocrinopathies but less commonly can involve other organs, resulting in uveitis, nephritis, myopathy, and neuropathy.

In general, the onset of irAEs follows a certain pattern with cutaneous manifestations often presenting early in treatment, followed by gastrointestinal and hepatic events occurring about 2 months into therapy and endocrinopathies appearing even later.²³ In rare cases, severe AEs (eg, perforating colitis, toxic epidermal necrolysis) can occur and may require hospitalization.²⁴

Clinicians must be attentive to early signs of these AEs and promptly initiate immunosuppression with steroids or other immunosuppressive medications, which do not appear to diminish the antitumor immune effects.²⁵ Established management algorithms exist to guide clinicians. Given the occasional need for immunosuppression in this patient population, awareness of the possibility of opportunistic or rare infections is also important.

In phase 3 evaluation, the number of patients who had long-term survival exceeded the number of patients who had a classically defined disease response to treatment. Durable stable disease and late responses have been observed clinically and may be responsible for some of the beneficial outcomes.²⁶ If patients are asymptomatic and have minimal radiographic progression, it is reasonable to repeat imaging 1 to 2 months later to confirm progression before considering additional lines of therapy.

Antibodies Blocking the Programmed Death-1 Axis

Programmed death-1 (PD-1) is a receptor on the surface of T cells that is upregulated at later stages of T-cell activation as opposed to the early upregulation of CTLA-4. Normally, engagement of PD-1 attenuates T-cell activity at several phases of an immune response. Tumors are believed to escape immune attack by similarly inhibiting T-cell activity by upregulating one of the ligands of PD-1, PD-L1.^27,28 Several antibodies that inhibit PD-1 activity, either by blocking the PD-1 molecule itself or PD-L1, are demonstrating significant promise in ongoing clinical trials.

Nivolumab (previously, BMS-936558) is a fully human monoclonal antibody targeting PD-1. In a large phase 1 study in patients with a variety of malignancies, nivolumab demonstrated a 31% RR in patients with advanced melanoma.²⁹ Subsequent follow-up data indicates these responses are generally durable with a median duration of response of 24 months and a 3-year OS rate of 40%.³⁰ Adverse effects of nivolumab appear less frequently than with CTLA-4 blockade but have included vitiligo, colitis, hepatitis, hypophysitis, and thyroiditis. Unique to PD-1 blockade appears to be the AE of an inflammatory pneumonitis, which can present with a dry cough, dyspnea, and ground-glass opacities and can be potentially lethal.²⁹

On the basis of complementary regulatory roles of CTLA-4 and PD-1 checkpoint inhibition, a trial investigating combined nivolumab and ipilimumab was completed. In the small group of patients treated, a high RR was seen with a generally acceptable safety profile.³¹ Ongoing phase 2 and 3 trials are assessing nivolumab alone and in combination with other agents for the treatment of advanced melanoma and other malignancies (Table 1).

Another PD-1 blocking antibody, MK-3475, has been evaluated in patients with advanced melanoma, and promising RRs have been described.³² In a small group of patients, the confirmed RR at a dose of 10 mg/kg every 2 weeks was 52% and appeared similar in patients who had and who had not been previously treated with ipilimumab. The AEs of MK-3475 seem to resemble nivolumab. MK-3475 is similarly being evaluated in large phase 2 and 3 trials for both patients with melanoma and additional malignancies.

In addition to antibodies targeting PD-1, clinical activity has also been observed with several different antibodies (BMS-936559, MPDL3280A, and MEDI4736) that target PD-L1. Though some data have been published for this therapeutic strategy,³³ ongoing trials will continue to clarify the role of targeting PD-L1 in patients with advanced melanoma.

Targeted Therapies That Block Oncogenic Signaling Pathways

The mitogen-activated protein kinase (MAPK) pathway responds to extracellular growth signals and regulates cell proliferation and survival. In many patients with melanoma, the MAPK pathway is constitutively activated as a result of molecular alterations in genes encoding key regulators or components of the pathway such as BRAF, NRAS, and KIT.^34,35 The most common mutation arising in melanoma is the BRAF mutation, occurring in nearly half of melanomas, and typically involves a missense mutation in which glutamic acid is substituted for valine at codon 600 (BRAF V600E mutation).³⁶ Less frequent BRAF mutations include V600K, V600R, and K601E.³⁷ Strategies that directly inhibit oncogenic BRAF or disable downstream elements such as MEK have recently shown dramatic results in patients with melanoma (Figure 2).

BRAF inhibitors

Vemurafenib is a potent inhibitor of mutated BRAF with marked antitumor effects against melanoma cell lines with the BRAF V600E mutation.³⁸ The first striking results of tumor regression with this strategy in patients were seen in a phase 1 study in patients with melanoma characterized by a BRAF V600E mutation but not in patients whose melanomas did not have a BRAF mutation.³⁹

Subsequent phase 3 trials confirmed the high RRs of this agent in patients with BRAF-mutant melanoma and demonstrated superiority in OS compared with dacarbazine chemotherapy.⁴⁰ The results of this phase 3 trial led to the approval of vemurafenib by the FDA in August 2011 with treatment exclusively limited to patients with BRAF mutant melanoma. Updated OS data from this phase 3 study revealed a median OS of 13.2 months for vemurafenib, compared with 9.6 months for dacarbazine, with an overall RR in patients treated with vemurafenib of 57% and a median PFS of 6.9 months.⁴¹ General AEs with vemurafenib include arthralgia, fatigue, aminotransferase elevations, nausea and vomiting, and decreased kidney function. In general, toxicities are manageable with dose reduction or temporary drug cessation.

One characteristic of vemurafenib and other BRAF-targeted agents is the frequent development of hyperproliferative skin AEs. Skin lesions, including follicular and palmo-plantar hyperkeratosis, papillomas, and also cutaneous squamous-cell carcinomas and keratoacanthomas, have commonly been observed under treatment with vemurafenib, and close evaluation by a dermatologist is important.⁴² The mechanism of this phenomenon is believed to be a paradoxical activation of the MAPK pathway in nonmelanoma BRAF wild-type cells when systemic treatment with a BRAF inhibitor is administered.⁴³

The phenomenon of hyperproliferation of non–BRAF-mutant tissues with ongoing BRAF-inhibitor therapy has also been seen in patients with lymphoproliferative disorders and may be a mechanism involved in the discovery that patients have a high rate of new primary melanomas while on therapy.^44,45 These findings warrant special attention, particularly as BRAF inhibitors are undergoing evaluation as adjuvant therapy.

Another active BRAF kinase inhibitor with a similar efficacy profile as vemurafenib is dabrafenib, which was approved in May 2013 based on the demonstration of improved PFS in a phase 3 trial comparing dabrafenib 150 mg orally twice daily and dacarbazine 1,000 mg/m² intravenously once every 3 weeks in previously untreated patients with BRAF V600E mutant melanoma. The median PFS times were 5.1 and 2.7 months in the dabrafenib and dacarbazine arms, respectively, with an objective RR of 52% in patients treated with dabrafenib.⁴⁶ Follow-up time was too short to make a determination of the impact of dabrafenib on OS. In a separate study, dabrafenib was also shown to be effective for patients with brain metastases and remains an excellent therapeutic choice for this particular patient population.⁴⁷

Generally, dabrafenib is believed to have similar efficacy to vemurafenib. Nevertheless, EAs with of dabrafenib differ somewhat from those observed with vemurafenib: The rate of proliferative skin lesions, including squamous cell carcinomas and keratoacanthomas appears to be lower for dabrafenib than vemurafenib. However, AEs particular to dabrafenib have been seen such as pyrexia, which were recorded in about 11% of patients.⁴⁶

MEK inhibitors

Though targeting oncogenic BRAF directly has been incredibly successful for patients with BRAF-mutant metastatic melanoma, additional success has been observed by blocking the MAPK pathway at a downstream component, MEK. Trametinib is an MEK inhibitor that was approved by the FDA in June 2013 as a single agent for patients with BRAF V600E or V600K mutant melanoma. Trametinib is administered at a dose of 2 mg once daily and was shown to improve PFS and OS compared with dacarbazine and paclitaxel chemotherapies.⁴⁷ Despite the improvement in PFS and OS compared with chemotherapy, the objective RR for trametinib was somewhat lower (22%) than that seen with BRAF inhibitors.

Trametinib also is associated with a different AE profile from BRAF inhibitors and includes diarrhea, peripheral edema, hypertension, and fatigue, typical of other MEK inhibitors as well.⁴⁸ Asymptomatic and reversible reduction of the cardiac ejection fraction and ocular toxic effects also occur infrequently. Unlike with BRAF-inhibitor treatment, the development of cutaneous squamous-cell carcinomas or other hyperproliferative skin lesions was not noted.⁴⁹

Despite the significant benefits of targeted therapy disrupting overly active MAPK signaling in patients with BRAF-mutant metastatic melanoma, almost all patients treated with these targeted inhibitors who achieve an initial response will ultimately progress. Several mechanisms of resistance have been proposed, and most relate to reactivation of the MAPK pathway.^50,51 As a result, efforts to maintain suppression of the MAPK pathway have been pursued to delay the onset of resistance. In a phase 2 trial that combined dabrafenib with trametinib, there was a longer PFS than there was with dabrafenib monotherapy.⁵²

Furthermore, the addition of trametinib to dabrafenib reduced the incidence of squamous-cell carcinoma, providing further evidence that reactivation of the MAPK pathway is involved in these hyperproliferative skin lesions arising under BRAF-directed therapy. A higher rate of febrile episodes was seen, however. An ongoing phase 3 study is looking at whether or not combining BRAF and MEK inhibitors results in improved OS compared with single-agent BRAF. It is premature at this juncture to recommend combining dabrafenib and trametinib until the results of the ongoing phase 3 studies more thoroughly describe the risks and benefits of this approach (Table 2).

KIT inhibitors

In a subset of melanomas, particularly those that arise from mucosal, acral, or chronically sun-damaged skin, mutations are found in the receptor-tyrosine kinase KIT.³⁵ A number of agents directed against KIT, such as imatinib, have been tested in clinical trials. Initial phase 2 studies revealed poor RRs with KIT inhibition in molecularly unselected patients.^53-55 Subsequent studies selected patients with KIT genetic aberrations, including mutations and amplifications, and some responses were seen.^56-58

Importantly, not all KIT genetic aberrations are believed to be considered equal. Preliminarily, it appears that mutations in exon 11 (L576P) and exon 13 (K642E) appear to be most closely associated with response and may be true driver mutations. Other KIT mutations may have less functional significance but additional research is needed. Imatinib is a reasonable therapeutic choice in patients with a KIT mutation, particularly when an L576P or K642E mutation is present.

conclusions

Since 2011, 4 new drugs—ipilimumab, vemurafenib, dabrafenib, and trametinib—have been approved for the treatment of metastatic melanoma. Exciting early data from PD-1 clinical trials suggest that agents that disrupt PD-1 may also become important therapeutic modalities. Future studies will continue to evaluate combinations of these therapeutic modalities, but caution should be exercised in combining these drugs prior to data from ongoing clinical trials revealing the true benefits and risks of combination therapy. Excessive toxicity was seen in an early phase trial when vemurafenib was combined with ipilimumab.⁵⁹

Additional research will also explore biomarkers that may help clinicians apply immunotherapy to the most appropriate patients and better understand mechanisms of resistance to targeted therapies. Clinical trials of novel agents or combinations should be considered at every treatment juncture to continue the rapid pace of developing the most innovative and tailored treatment approaches.  

Author disclosures
The authors report no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.

This article has been adapted from an article originally published in The Journal of Supportive and Community Oncology (jcso-online.com). Schindler K, Postow M. Current options and future directions in the systemic treatment of metastatic melanoma. J Community Support Oncol. 2014;12(1):20-26. 

The incidence of melanoma, a highly aggressive tumor arising from melanocytes, continues to rise by about 3% a year in the U.S. with about 76,000 patients being diagnosed every year and 9,000 patients dying of the disease.¹ Complete surgical resection is the standard for localized melanoma, with surgical excision margins depending on tumor thickness. For patients with involved sentinel lymph nodes, complete lymphadenectomy is typically recommended, although the benefits of completion lymphadenectomy are being evaluated in an ongoing randomized trial.^2,3

For patients with surgically resected, high-risk melanoma, the only approved adjuvant therapy is interferon-a (IFN-a).⁴ Use of IFN-a, however, remains controversial because of the associated adverse effects (AEs) and controversial effects on overall survival (OS).^5,6 Unfortunately, many patients with localized disease will ultimately experience a recurrence, and the prognosis of patients with metastatic disease is poor with a historical 5-year survival rate of 10%.⁷

Chemotherapy and interleukin 2

For more than 3 decades, conventional cytotoxic chemotherapy was used to treat metastatic melanoma. Typical agents included alkylating agents (dacarbazine, temozolomide, nitrosoureas), platinum analogs (cisplatin and carboplatin), and microtubular toxins (vinblastine and paclitaxel). Despite the clinical use and investigation of a number of these chemotherapies for patients with metastatic melanoma, the only treatment approved by the FDA is dacarbazine, which is administered intravenously every 3 to 4 weeks at a dose of 800 to 1,000 mg/m².

Monotherapy with dacarbazine is generally well tolerated with only mild AEs such as nausea, myelosuppression, and fatigue. In a pooled analysis, the overall response rate (RR) for dacarbazine was approximately 9%.⁸ Temozolomide, the oral analog of dacarbazine, penetrates into the central nervous system and has been compared with dacarbazine in randomized trials. These agents are believed to have similar efficacy, but temozolomide has been associated with a higher rate of lymphopenia.^9,10

Investigation of chemotherapy combinations such as cisplatin, vinblastine, and dacarbazine or carboplatin and paclitaxel have shown promising RRs but unfortunately no prolongation of OS compared with single-agent dacarbazine.^11-13 Despite its modest efficacy, chemotherapy still has a place in the palliative treatment for some patients.

In addition to dacarbazine, the immunotherapeutic strategy, high-dose recombinant interleukin-2 (IL-2), had also been a mainstay treatment for advanced melanoma for many years. IL-2 is administered as an IV infusion every 8 hours at a dose of 600,000 to 720,000  IU/kg on days 1 to 5 and days 15 to 19, with a maximum of 14 such biphasic cycles. Because of the significant acute toxicity profile, including capillary leak syndrome, cardiovascular complications, and seizures, IL-2 treatment requires hospitalization and is generally only performed at specialized centers for patients with good performance status. Though the overall RR in pooled analysis was low at 16%, the durability of responses in some responders that appeared to last many years led to the FDA approval of IL-2 in 1998.^14,15

IL-2 continues to be investigated. In a randomized trial, an improved RR and progression-free survival (PFS) were seen when IL-2 was combined with the glycoprotein 100 (gp100) peptide vaccine compared with IL-2 alone.¹⁶ Other approaches have sought to improve the safety of IL-2 by selectively delivering it to tumor sites. The fusion protein L19-IL2 couples IL-2 with the recombinant human vascular targeting antibody L19 and has preliminarily been shown to be safe in phase 1 evaluation and in combination with dacarbazine.^17,18

Antibodies that block immunologic checkpoints

Melanoma has long been recognized as an immunogenic malignancy but the efficacy of immunotherapeutic strategies has generally been modest. The precise etiology of why immunotherapy historically was not more successful is not completely understood, but it is possible that patients with advanced malignancy have predominant immune inhibitory circuits that prevent otherwise effective antitumor immune responses.

In recent years, research has illuminated some of these immunologic inhibitory elements, termed “immunologic checkpoints,” which include cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1). Antibodies that target these checkpoints have resulted in durable responses in some patients and a unique pattern of immune-mediated AEs. Though an ongoing area of research, no pre- or on-treatment biomarkers have been sufficiently validated to enable specific patient selection for these therapies.

Antibodies Blocking CTLA-4

CTLA-4 is expressed on activated T cells and typically functions as a negative regulator of T-cell activity preserving normal immunologic homeostasis. Blocking CTLA-4 with therapeutic antibodies such as ipilimumab and tremelimumab prevents normal CTLA-4–mediated T-cell downregulation and thereby enhances the ability of T cells to exert their full antitumor immune effects (Figure 1). Ipilimumab was the first drug in the management of metastatic melanoma to show an improvement in OS in phase 3 studies, and although a phase 3 study of tremelimumab did not demonstrate an improvement in OS, durable responses were similarly seen.^19-21

The first phase 3 trial investigating ipilimumab randomized previously pretreated patients with advanced melanoma to ipilimumab at a dose of 3 mg/kg with or without the gp100 peptide vaccine. The median OS was 10.0 months among patients receiving ipilimumab plus gp100, compared with 6.4 months among patients receiving gp100 alone. There was no difference in OS between the ipilimumab groups.¹⁹ The outcome of this study has led to the approval of ipilimumab at a dose of 3 mg/kg in patients with advanced melanoma by regulatory agencies in the U.S., European Union, and Australia.

For treatment-naive patients, a second phase 3 trial investigating dacarbazine in combination with ipilimumab compared with dacarbazine in combination with placebo also demonstrated improvement of OS in patients treated with dacarbazine in combination with ipilimumab.²⁰ The estimated 1-year, 2-year, and 3-year survival rates were 47.3%, 28.5%, and 20.8%, respectively, in the dacarbazine plus ipilimumab group, compared with 36.3%, 17.9%, and 12.2% in the dacarbazine alone group. This second trial used a higher dose of ipilimumab (10 mg/kg) and though it confirmed ipilimumab’s beneficial effects on OS, ipilimumab is not approved at 10 mg/kg and is not routinely recommended to be used in combination with dacarbazine given hepatic toxicity concerns.

Though the median OS was improved in these phase 3 trials, perhaps the greatest activity of ipilimumab lies in the increased number of patients who can achieve long-term OS. In a recently published updated survival analysis, the 4-year survival rates for previously treated patients who received ipilimumab at 3 or 10 mg/kg were 18.2% and 19.7% to 28.4%. For treatment-naive patients receiving ipilimumab at 10 mg/kg, 4-year survival rates were between 37.7% and 49.5%.²² These values appear superior to historical data from prior chemotherapy trials.

An important consideration in the clinical use of CTLA-4 blocking antibodies is the possible occurrence of toxicities that differ from those associated with traditional chemotherapy. These AEs are termed immune-related AEs (irAEs), and they most commonly manifest as diarrhea, dermatitis, hepatitis, and endocrinopathies but less commonly can involve other organs, resulting in uveitis, nephritis, myopathy, and neuropathy.

In general, the onset of irAEs follows a certain pattern with cutaneous manifestations often presenting early in treatment, followed by gastrointestinal and hepatic events occurring about 2 months into therapy and endocrinopathies appearing even later.²³ In rare cases, severe AEs (eg, perforating colitis, toxic epidermal necrolysis) can occur and may require hospitalization.²⁴

Clinicians must be attentive to early signs of these AEs and promptly initiate immunosuppression with steroids or other immunosuppressive medications, which do not appear to diminish the antitumor immune effects.²⁵ Established management algorithms exist to guide clinicians. Given the occasional need for immunosuppression in this patient population, awareness of the possibility of opportunistic or rare infections is also important.

In phase 3 evaluation, the number of patients who had long-term survival exceeded the number of patients who had a classically defined disease response to treatment. Durable stable disease and late responses have been observed clinically and may be responsible for some of the beneficial outcomes.²⁶ If patients are asymptomatic and have minimal radiographic progression, it is reasonable to repeat imaging 1 to 2 months later to confirm progression before considering additional lines of therapy.

Antibodies Blocking the Programmed Death-1 Axis

Programmed death-1 (PD-1) is a receptor on the surface of T cells that is upregulated at later stages of T-cell activation as opposed to the early upregulation of CTLA-4. Normally, engagement of PD-1 attenuates T-cell activity at several phases of an immune response. Tumors are believed to escape immune attack by similarly inhibiting T-cell activity by upregulating one of the ligands of PD-1, PD-L1.^27,28 Several antibodies that inhibit PD-1 activity, either by blocking the PD-1 molecule itself or PD-L1, are demonstrating significant promise in ongoing clinical trials.

Nivolumab (previously, BMS-936558) is a fully human monoclonal antibody targeting PD-1. In a large phase 1 study in patients with a variety of malignancies, nivolumab demonstrated a 31% RR in patients with advanced melanoma.²⁹ Subsequent follow-up data indicates these responses are generally durable with a median duration of response of 24 months and a 3-year OS rate of 40%.³⁰ Adverse effects of nivolumab appear less frequently than with CTLA-4 blockade but have included vitiligo, colitis, hepatitis, hypophysitis, and thyroiditis. Unique to PD-1 blockade appears to be the AE of an inflammatory pneumonitis, which can present with a dry cough, dyspnea, and ground-glass opacities and can be potentially lethal.²⁹

On the basis of complementary regulatory roles of CTLA-4 and PD-1 checkpoint inhibition, a trial investigating combined nivolumab and ipilimumab was completed. In the small group of patients treated, a high RR was seen with a generally acceptable safety profile.³¹ Ongoing phase 2 and 3 trials are assessing nivolumab alone and in combination with other agents for the treatment of advanced melanoma and other malignancies (Table 1).

Another PD-1 blocking antibody, MK-3475, has been evaluated in patients with advanced melanoma, and promising RRs have been described.³² In a small group of patients, the confirmed RR at a dose of 10 mg/kg every 2 weeks was 52% and appeared similar in patients who had and who had not been previously treated with ipilimumab. The AEs of MK-3475 seem to resemble nivolumab. MK-3475 is similarly being evaluated in large phase 2 and 3 trials for both patients with melanoma and additional malignancies.

In addition to antibodies targeting PD-1, clinical activity has also been observed with several different antibodies (BMS-936559, MPDL3280A, and MEDI4736) that target PD-L1. Though some data have been published for this therapeutic strategy,³³ ongoing trials will continue to clarify the role of targeting PD-L1 in patients with advanced melanoma.

Targeted Therapies That Block Oncogenic Signaling Pathways

The mitogen-activated protein kinase (MAPK) pathway responds to extracellular growth signals and regulates cell proliferation and survival. In many patients with melanoma, the MAPK pathway is constitutively activated as a result of molecular alterations in genes encoding key regulators or components of the pathway such as BRAF, NRAS, and KIT.^34,35 The most common mutation arising in melanoma is the BRAF mutation, occurring in nearly half of melanomas, and typically involves a missense mutation in which glutamic acid is substituted for valine at codon 600 (BRAF V600E mutation).³⁶ Less frequent BRAF mutations include V600K, V600R, and K601E.³⁷ Strategies that directly inhibit oncogenic BRAF or disable downstream elements such as MEK have recently shown dramatic results in patients with melanoma (Figure 2).

BRAF inhibitors

Vemurafenib is a potent inhibitor of mutated BRAF with marked antitumor effects against melanoma cell lines with the BRAF V600E mutation.³⁸ The first striking results of tumor regression with this strategy in patients were seen in a phase 1 study in patients with melanoma characterized by a BRAF V600E mutation but not in patients whose melanomas did not have a BRAF mutation.³⁹

Subsequent phase 3 trials confirmed the high RRs of this agent in patients with BRAF-mutant melanoma and demonstrated superiority in OS compared with dacarbazine chemotherapy.⁴⁰ The results of this phase 3 trial led to the approval of vemurafenib by the FDA in August 2011 with treatment exclusively limited to patients with BRAF mutant melanoma. Updated OS data from this phase 3 study revealed a median OS of 13.2 months for vemurafenib, compared with 9.6 months for dacarbazine, with an overall RR in patients treated with vemurafenib of 57% and a median PFS of 6.9 months.⁴¹ General AEs with vemurafenib include arthralgia, fatigue, aminotransferase elevations, nausea and vomiting, and decreased kidney function. In general, toxicities are manageable with dose reduction or temporary drug cessation.

One characteristic of vemurafenib and other BRAF-targeted agents is the frequent development of hyperproliferative skin AEs. Skin lesions, including follicular and palmo-plantar hyperkeratosis, papillomas, and also cutaneous squamous-cell carcinomas and keratoacanthomas, have commonly been observed under treatment with vemurafenib, and close evaluation by a dermatologist is important.⁴² The mechanism of this phenomenon is believed to be a paradoxical activation of the MAPK pathway in nonmelanoma BRAF wild-type cells when systemic treatment with a BRAF inhibitor is administered.⁴³

The phenomenon of hyperproliferation of non–BRAF-mutant tissues with ongoing BRAF-inhibitor therapy has also been seen in patients with lymphoproliferative disorders and may be a mechanism involved in the discovery that patients have a high rate of new primary melanomas while on therapy.^44,45 These findings warrant special attention, particularly as BRAF inhibitors are undergoing evaluation as adjuvant therapy.

Another active BRAF kinase inhibitor with a similar efficacy profile as vemurafenib is dabrafenib, which was approved in May 2013 based on the demonstration of improved PFS in a phase 3 trial comparing dabrafenib 150 mg orally twice daily and dacarbazine 1,000 mg/m² intravenously once every 3 weeks in previously untreated patients with BRAF V600E mutant melanoma. The median PFS times were 5.1 and 2.7 months in the dabrafenib and dacarbazine arms, respectively, with an objective RR of 52% in patients treated with dabrafenib.⁴⁶ Follow-up time was too short to make a determination of the impact of dabrafenib on OS. In a separate study, dabrafenib was also shown to be effective for patients with brain metastases and remains an excellent therapeutic choice for this particular patient population.⁴⁷

Generally, dabrafenib is believed to have similar efficacy to vemurafenib. Nevertheless, EAs with of dabrafenib differ somewhat from those observed with vemurafenib: The rate of proliferative skin lesions, including squamous cell carcinomas and keratoacanthomas appears to be lower for dabrafenib than vemurafenib. However, AEs particular to dabrafenib have been seen such as pyrexia, which were recorded in about 11% of patients.⁴⁶

MEK inhibitors

Though targeting oncogenic BRAF directly has been incredibly successful for patients with BRAF-mutant metastatic melanoma, additional success has been observed by blocking the MAPK pathway at a downstream component, MEK. Trametinib is an MEK inhibitor that was approved by the FDA in June 2013 as a single agent for patients with BRAF V600E or V600K mutant melanoma. Trametinib is administered at a dose of 2 mg once daily and was shown to improve PFS and OS compared with dacarbazine and paclitaxel chemotherapies.⁴⁷ Despite the improvement in PFS and OS compared with chemotherapy, the objective RR for trametinib was somewhat lower (22%) than that seen with BRAF inhibitors.

Trametinib also is associated with a different AE profile from BRAF inhibitors and includes diarrhea, peripheral edema, hypertension, and fatigue, typical of other MEK inhibitors as well.⁴⁸ Asymptomatic and reversible reduction of the cardiac ejection fraction and ocular toxic effects also occur infrequently. Unlike with BRAF-inhibitor treatment, the development of cutaneous squamous-cell carcinomas or other hyperproliferative skin lesions was not noted.⁴⁹

Despite the significant benefits of targeted therapy disrupting overly active MAPK signaling in patients with BRAF-mutant metastatic melanoma, almost all patients treated with these targeted inhibitors who achieve an initial response will ultimately progress. Several mechanisms of resistance have been proposed, and most relate to reactivation of the MAPK pathway.^50,51 As a result, efforts to maintain suppression of the MAPK pathway have been pursued to delay the onset of resistance. In a phase 2 trial that combined dabrafenib with trametinib, there was a longer PFS than there was with dabrafenib monotherapy.⁵²

Furthermore, the addition of trametinib to dabrafenib reduced the incidence of squamous-cell carcinoma, providing further evidence that reactivation of the MAPK pathway is involved in these hyperproliferative skin lesions arising under BRAF-directed therapy. A higher rate of febrile episodes was seen, however. An ongoing phase 3 study is looking at whether or not combining BRAF and MEK inhibitors results in improved OS compared with single-agent BRAF. It is premature at this juncture to recommend combining dabrafenib and trametinib until the results of the ongoing phase 3 studies more thoroughly describe the risks and benefits of this approach (Table 2).

KIT inhibitors

In a subset of melanomas, particularly those that arise from mucosal, acral, or chronically sun-damaged skin, mutations are found in the receptor-tyrosine kinase KIT.³⁵ A number of agents directed against KIT, such as imatinib, have been tested in clinical trials. Initial phase 2 studies revealed poor RRs with KIT inhibition in molecularly unselected patients.^53-55 Subsequent studies selected patients with KIT genetic aberrations, including mutations and amplifications, and some responses were seen.^56-58

Importantly, not all KIT genetic aberrations are believed to be considered equal. Preliminarily, it appears that mutations in exon 11 (L576P) and exon 13 (K642E) appear to be most closely associated with response and may be true driver mutations. Other KIT mutations may have less functional significance but additional research is needed. Imatinib is a reasonable therapeutic choice in patients with a KIT mutation, particularly when an L576P or K642E mutation is present.

conclusions

Since 2011, 4 new drugs—ipilimumab, vemurafenib, dabrafenib, and trametinib—have been approved for the treatment of metastatic melanoma. Exciting early data from PD-1 clinical trials suggest that agents that disrupt PD-1 may also become important therapeutic modalities. Future studies will continue to evaluate combinations of these therapeutic modalities, but caution should be exercised in combining these drugs prior to data from ongoing clinical trials revealing the true benefits and risks of combination therapy. Excessive toxicity was seen in an early phase trial when vemurafenib was combined with ipilimumab.⁵⁹

Additional research will also explore biomarkers that may help clinicians apply immunotherapy to the most appropriate patients and better understand mechanisms of resistance to targeted therapies. Clinical trials of novel agents or combinations should be considered at every treatment juncture to continue the rapid pace of developing the most innovative and tailored treatment approaches.  

Author disclosures
The authors report no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.

The US Food and Drug Administration (FDA) has approved bortezomib (Velcade) for the retreatment of adults with multiple myeloma (MM) who previously responded to bortezomib and relapsed at least 6 months after that treatment.

Bortezomib’s label has been updated to include dosing guidelines and safety and efficacy findings for single-agent bortezomib and bortezomib in combination with dexamethasone in patients previously treated with bortezomib.

Bortezomib retreatment may be started at the last dose the patient tolerated.

The FDA approved bortezomib retreatment based on results of the phase 2 RETRIEVE study and other supportive data.

The single-arm RETRIEVE trial included 130 MM patients aged 18 years and older who had previously responded to bortezomib-based therapy and relapsed at least 6 months after the treatment. The patients had received a median of 2 prior therapies (range, 1 to 7).

In this study, 94 of the patients received bortezomib in combination with dexamethasone.

One patient achieved complete response to treatment, and 49 achieved partial responses, for an overall response rate of 38.5%. The median duration of response was 6.5 months (range, 0.6 to 19.3 months).

The safety profile with bortezomib retreatment was consistent with the known safety profile of intravenous bortezomib in relapsed MM. Researchers did not observer cumulative toxicities upon retreatment.

The most common adverse event was thrombocytopenia, which occurred in 52% of patients. The incidence of grade 3 or higher thrombocytopenia was 24%.

Peripheral neuropathy was also common, occurring in 28% of patients. Grade 3 or higher peripheral neuropathy occurred in 6% of patients.

The rate of serious adverse events was 12.3%. The most commonly reported serious adverse events were thrombocytopenia (3.8%), diarrhea (2.3%), herpes zoster (1.5%), and pneumonia (1.5%). Adverse events leading to discontinuation occurred in 13% of patients.

Bortezomib is co-developed by Millennium/Takeda and Janssen Pharmaceutical Companies. Millennium is responsible for commercialization of bortezomib in the US. Janssen Pharmaceutical Companies are responsible for commercialization in Europe and the rest of the world.

Takeda Pharmaceutical Company Limited and Janssen Pharmaceutical K.K. co-promote bortezomib in Japan. Bortezomib is approved in more than 90 countries.

The US Food and Drug Administration (FDA) has approved bortezomib (Velcade) for the retreatment of adults with multiple myeloma (MM) who previously responded to bortezomib and relapsed at least 6 months after that treatment.

Bortezomib’s label has been updated to include dosing guidelines and safety and efficacy findings for single-agent bortezomib and bortezomib in combination with dexamethasone in patients previously treated with bortezomib.

Bortezomib retreatment may be started at the last dose the patient tolerated.

The FDA approved bortezomib retreatment based on results of the phase 2 RETRIEVE study and other supportive data.

The single-arm RETRIEVE trial included 130 MM patients aged 18 years and older who had previously responded to bortezomib-based therapy and relapsed at least 6 months after the treatment. The patients had received a median of 2 prior therapies (range, 1 to 7).

In this study, 94 of the patients received bortezomib in combination with dexamethasone.

One patient achieved complete response to treatment, and 49 achieved partial responses, for an overall response rate of 38.5%. The median duration of response was 6.5 months (range, 0.6 to 19.3 months).

The safety profile with bortezomib retreatment was consistent with the known safety profile of intravenous bortezomib in relapsed MM. Researchers did not observer cumulative toxicities upon retreatment.

The most common adverse event was thrombocytopenia, which occurred in 52% of patients. The incidence of grade 3 or higher thrombocytopenia was 24%.

Peripheral neuropathy was also common, occurring in 28% of patients. Grade 3 or higher peripheral neuropathy occurred in 6% of patients.

The rate of serious adverse events was 12.3%. The most commonly reported serious adverse events were thrombocytopenia (3.8%), diarrhea (2.3%), herpes zoster (1.5%), and pneumonia (1.5%). Adverse events leading to discontinuation occurred in 13% of patients.

Bortezomib is co-developed by Millennium/Takeda and Janssen Pharmaceutical Companies. Millennium is responsible for commercialization of bortezomib in the US. Janssen Pharmaceutical Companies are responsible for commercialization in Europe and the rest of the world.

Takeda Pharmaceutical Company Limited and Janssen Pharmaceutical K.K. co-promote bortezomib in Japan. Bortezomib is approved in more than 90 countries.

The US Food and Drug Administration (FDA) has approved bortezomib (Velcade) for the retreatment of adults with multiple myeloma (MM) who previously responded to bortezomib and relapsed at least 6 months after that treatment.

Bortezomib’s label has been updated to include dosing guidelines and safety and efficacy findings for single-agent bortezomib and bortezomib in combination with dexamethasone in patients previously treated with bortezomib.

Bortezomib retreatment may be started at the last dose the patient tolerated.

The FDA approved bortezomib retreatment based on results of the phase 2 RETRIEVE study and other supportive data.

The single-arm RETRIEVE trial included 130 MM patients aged 18 years and older who had previously responded to bortezomib-based therapy and relapsed at least 6 months after the treatment. The patients had received a median of 2 prior therapies (range, 1 to 7).

In this study, 94 of the patients received bortezomib in combination with dexamethasone.

One patient achieved complete response to treatment, and 49 achieved partial responses, for an overall response rate of 38.5%. The median duration of response was 6.5 months (range, 0.6 to 19.3 months).

The safety profile with bortezomib retreatment was consistent with the known safety profile of intravenous bortezomib in relapsed MM. Researchers did not observer cumulative toxicities upon retreatment.

The most common adverse event was thrombocytopenia, which occurred in 52% of patients. The incidence of grade 3 or higher thrombocytopenia was 24%.

Peripheral neuropathy was also common, occurring in 28% of patients. Grade 3 or higher peripheral neuropathy occurred in 6% of patients.

The rate of serious adverse events was 12.3%. The most commonly reported serious adverse events were thrombocytopenia (3.8%), diarrhea (2.3%), herpes zoster (1.5%), and pneumonia (1.5%). Adverse events leading to discontinuation occurred in 13% of patients.

Bortezomib is co-developed by Millennium/Takeda and Janssen Pharmaceutical Companies. Millennium is responsible for commercialization of bortezomib in the US. Janssen Pharmaceutical Companies are responsible for commercialization in Europe and the rest of the world.

Takeda Pharmaceutical Company Limited and Janssen Pharmaceutical K.K. co-promote bortezomib in Japan. Bortezomib is approved in more than 90 countries.

DNA helices

Credit: NIGMS

A new technique could enable faster diagnosis of cancer and various prenatal conditions, according to a paper published in Proceedings of the National Academy of Sciences.

The method, known as convex lens-induced confinement (CLIC), allows researchers to load long strands of DNA into a tunable, nanoscale imaging chamber in ways that maintain their structural identity and under conditions that are similar to those in the human body.

CLIC lets researchers map large genomes rapidly and identify specific gene sequences from single cells with single-molecule resolution, a process that is critical to diagnosing diseases like cancer.

“Current practices of genomic analysis typically require tens of thousands of cells worth of genomic material to obtain the information we need, but this new approach works with single cells,” said study author Rob Sladek, MD, of McGill University in Montreal, Canada.

“CLIC will allow researchers to avoid having to spend time stitching together maps of entire genomes, as we do under current techniques, and promises to make genomic analysis a much simpler and more efficient process.”

The CLIC imaging chamber can sit on top of a standard inverted fluorescence microscope, and strands of DNA can be loaded into the chamber from above, which allows the strands to maintain their integrity.

Existing tools used for genomic analysis rely on side-loading DNA under pressure into nanochannels in the imaging chamber. This breaks the DNA molecules into small pieces, making it a challenge to reconstruct the genome.

CLIC, on the other hand, is “like squeezing many soft spaghetti noodles into long, narrow tubes without breaking them,” according to study author Sabrina Leslie, PhD, also of McGill University.

“Once these long strands of DNA are gently squeezed down into nanochannels from a nanoscale bath above, they become effectively rigid, which means that we can map positions along uniformly stretched strands of DNA, while holding them still,” she said.

“This means diagnostics can be performed quickly, one cell at a time, which is critical for diagnosing many prenatal conditions and the onset of cancer.”

DNA helices

Credit: NIGMS

A new technique could enable faster diagnosis of cancer and various prenatal conditions, according to a paper published in Proceedings of the National Academy of Sciences.

The method, known as convex lens-induced confinement (CLIC), allows researchers to load long strands of DNA into a tunable, nanoscale imaging chamber in ways that maintain their structural identity and under conditions that are similar to those in the human body.

CLIC lets researchers map large genomes rapidly and identify specific gene sequences from single cells with single-molecule resolution, a process that is critical to diagnosing diseases like cancer.

“Current practices of genomic analysis typically require tens of thousands of cells worth of genomic material to obtain the information we need, but this new approach works with single cells,” said study author Rob Sladek, MD, of McGill University in Montreal, Canada.

“CLIC will allow researchers to avoid having to spend time stitching together maps of entire genomes, as we do under current techniques, and promises to make genomic analysis a much simpler and more efficient process.”

The CLIC imaging chamber can sit on top of a standard inverted fluorescence microscope, and strands of DNA can be loaded into the chamber from above, which allows the strands to maintain their integrity.

Existing tools used for genomic analysis rely on side-loading DNA under pressure into nanochannels in the imaging chamber. This breaks the DNA molecules into small pieces, making it a challenge to reconstruct the genome.

CLIC, on the other hand, is “like squeezing many soft spaghetti noodles into long, narrow tubes without breaking them,” according to study author Sabrina Leslie, PhD, also of McGill University.

“Once these long strands of DNA are gently squeezed down into nanochannels from a nanoscale bath above, they become effectively rigid, which means that we can map positions along uniformly stretched strands of DNA, while holding them still,” she said.

“This means diagnostics can be performed quickly, one cell at a time, which is critical for diagnosing many prenatal conditions and the onset of cancer.”

DNA helices

Credit: NIGMS

A new technique could enable faster diagnosis of cancer and various prenatal conditions, according to a paper published in Proceedings of the National Academy of Sciences.

The method, known as convex lens-induced confinement (CLIC), allows researchers to load long strands of DNA into a tunable, nanoscale imaging chamber in ways that maintain their structural identity and under conditions that are similar to those in the human body.

CLIC lets researchers map large genomes rapidly and identify specific gene sequences from single cells with single-molecule resolution, a process that is critical to diagnosing diseases like cancer.

“Current practices of genomic analysis typically require tens of thousands of cells worth of genomic material to obtain the information we need, but this new approach works with single cells,” said study author Rob Sladek, MD, of McGill University in Montreal, Canada.

“CLIC will allow researchers to avoid having to spend time stitching together maps of entire genomes, as we do under current techniques, and promises to make genomic analysis a much simpler and more efficient process.”

The CLIC imaging chamber can sit on top of a standard inverted fluorescence microscope, and strands of DNA can be loaded into the chamber from above, which allows the strands to maintain their integrity.

Existing tools used for genomic analysis rely on side-loading DNA under pressure into nanochannels in the imaging chamber. This breaks the DNA molecules into small pieces, making it a challenge to reconstruct the genome.

CLIC, on the other hand, is “like squeezing many soft spaghetti noodles into long, narrow tubes without breaking them,” according to study author Sabrina Leslie, PhD, also of McGill University.

“Once these long strands of DNA are gently squeezed down into nanochannels from a nanoscale bath above, they become effectively rigid, which means that we can map positions along uniformly stretched strands of DNA, while holding them still,” she said.

“This means diagnostics can be performed quickly, one cell at a time, which is critical for diagnosing many prenatal conditions and the onset of cancer.”

Micrograph showing MF

Credit: Peter Anderson

The US Food and Drug Administration (FDA) is expediting its review of pacritinib, a tyrosine kinase inhibitor with activity against JAK2 and FLT3, by granting the drug fast track designation.

Pacritinib is under review as a treatment for patients with intermediate- and high-risk myelofibrosis (MF), including those with disease-related or treatment-induced thrombocytopenia and those who cannot tolerate or do not respond well to other JAK2 therapy.

The FDA’s fast track process is designed to expedite the review of drugs to treat serious conditions and fill an unmet medical need.

The program enables a company—in this case, CTI BioPharma—to submit sections of a new drug application on a rolling basis as data becomes available.

That way, the FDA can review sections of the application as they are received, rather than waiting until every section of the application is completed before the entire application can be reviewed. This often leads to faster approval.

Pacritinib is currently under investigation in two phase 3 clinical trials, known as the PERSIST program, for patients with MF.

One of these trials, known as PERSIST-1, includes a broad set of patients without limitations on platelet counts. The other, PERSIST-2, includes patients with low platelet counts.

PERSIST-1

In July 2014, CTI Biopharma completed enrollment in the PERSIST-1 trial, which was designed to enroll approximately 320 patients.

This randomized trial was designed to compared the efficacy and safety of pacritinib with that of best available therapy, other than JAK inhibitors, in patients with primary MF, post-polycythemia vera MF, or post-essential thrombocythemia MF, without exclusion for low platelet counts.

The primary endpoint is the percentage of patients achieving at least a 35% reduction in spleen volume, measured by MRI or CT from baseline to 24 weeks of treatment.

PERSIST-2

In March 2014, CTI announced the initiation of the PERSIST-2 trial, a comparison of pacritinib and best available therapy, including approved JAK2 inhibitors that are dosed according to product label, in patients with MF whose platelet counts are 100,000/uL or lower.

The trial is designed to enroll up to 300 patients in North America, Europe, Australia, and New Zealand. In October 2013, CTI reached agreement with the FDA on a special protocol assessment for the trial, a written agreement between CTI and the FDA regarding the planned design, endpoints, and statistical analysis approach of the trial to be used in support of a potential new drug application.

Under the special protocol assessment, the trial will have two primary endpoints. The first is the percentage of patients achieving a 35% or greater reduction in spleen volume, measured by MRI or CT scan from baseline to 24 weeks of treatment.

The second primary endpoint is the percentage of patients achieving a total symptom score reduction of 50% or greater using 6 key symptoms, as measured by the modified Myeloproliferative Neoplasm Symptom Assessment (MPN-SAF TSS 2.0) diary from baseline to 24 weeks.

More details on the PERSIST-1 and PERSIST-2 trials can be found at www.clinicaltrials.gov.

Micrograph showing MF

Credit: Peter Anderson

The US Food and Drug Administration (FDA) is expediting its review of pacritinib, a tyrosine kinase inhibitor with activity against JAK2 and FLT3, by granting the drug fast track designation.

Pacritinib is under review as a treatment for patients with intermediate- and high-risk myelofibrosis (MF), including those with disease-related or treatment-induced thrombocytopenia and those who cannot tolerate or do not respond well to other JAK2 therapy.

The FDA’s fast track process is designed to expedite the review of drugs to treat serious conditions and fill an unmet medical need.

The program enables a company—in this case, CTI BioPharma—to submit sections of a new drug application on a rolling basis as data becomes available.

That way, the FDA can review sections of the application as they are received, rather than waiting until every section of the application is completed before the entire application can be reviewed. This often leads to faster approval.

Pacritinib is currently under investigation in two phase 3 clinical trials, known as the PERSIST program, for patients with MF.

One of these trials, known as PERSIST-1, includes a broad set of patients without limitations on platelet counts. The other, PERSIST-2, includes patients with low platelet counts.

PERSIST-1

In July 2014, CTI Biopharma completed enrollment in the PERSIST-1 trial, which was designed to enroll approximately 320 patients.

This randomized trial was designed to compared the efficacy and safety of pacritinib with that of best available therapy, other than JAK inhibitors, in patients with primary MF, post-polycythemia vera MF, or post-essential thrombocythemia MF, without exclusion for low platelet counts.

The primary endpoint is the percentage of patients achieving at least a 35% reduction in spleen volume, measured by MRI or CT from baseline to 24 weeks of treatment.

PERSIST-2

In March 2014, CTI announced the initiation of the PERSIST-2 trial, a comparison of pacritinib and best available therapy, including approved JAK2 inhibitors that are dosed according to product label, in patients with MF whose platelet counts are 100,000/uL or lower.

The trial is designed to enroll up to 300 patients in North America, Europe, Australia, and New Zealand. In October 2013, CTI reached agreement with the FDA on a special protocol assessment for the trial, a written agreement between CTI and the FDA regarding the planned design, endpoints, and statistical analysis approach of the trial to be used in support of a potential new drug application.

Under the special protocol assessment, the trial will have two primary endpoints. The first is the percentage of patients achieving a 35% or greater reduction in spleen volume, measured by MRI or CT scan from baseline to 24 weeks of treatment.

The second primary endpoint is the percentage of patients achieving a total symptom score reduction of 50% or greater using 6 key symptoms, as measured by the modified Myeloproliferative Neoplasm Symptom Assessment (MPN-SAF TSS 2.0) diary from baseline to 24 weeks.

More details on the PERSIST-1 and PERSIST-2 trials can be found at www.clinicaltrials.gov.

Micrograph showing MF

Credit: Peter Anderson

The US Food and Drug Administration (FDA) is expediting its review of pacritinib, a tyrosine kinase inhibitor with activity against JAK2 and FLT3, by granting the drug fast track designation.

Pacritinib is under review as a treatment for patients with intermediate- and high-risk myelofibrosis (MF), including those with disease-related or treatment-induced thrombocytopenia and those who cannot tolerate or do not respond well to other JAK2 therapy.

The FDA’s fast track process is designed to expedite the review of drugs to treat serious conditions and fill an unmet medical need.

The program enables a company—in this case, CTI BioPharma—to submit sections of a new drug application on a rolling basis as data becomes available.

That way, the FDA can review sections of the application as they are received, rather than waiting until every section of the application is completed before the entire application can be reviewed. This often leads to faster approval.

Pacritinib is currently under investigation in two phase 3 clinical trials, known as the PERSIST program, for patients with MF.

One of these trials, known as PERSIST-1, includes a broad set of patients without limitations on platelet counts. The other, PERSIST-2, includes patients with low platelet counts.

PERSIST-1

In July 2014, CTI Biopharma completed enrollment in the PERSIST-1 trial, which was designed to enroll approximately 320 patients.

This randomized trial was designed to compared the efficacy and safety of pacritinib with that of best available therapy, other than JAK inhibitors, in patients with primary MF, post-polycythemia vera MF, or post-essential thrombocythemia MF, without exclusion for low platelet counts.

The primary endpoint is the percentage of patients achieving at least a 35% reduction in spleen volume, measured by MRI or CT from baseline to 24 weeks of treatment.

PERSIST-2

In March 2014, CTI announced the initiation of the PERSIST-2 trial, a comparison of pacritinib and best available therapy, including approved JAK2 inhibitors that are dosed according to product label, in patients with MF whose platelet counts are 100,000/uL or lower.

The trial is designed to enroll up to 300 patients in North America, Europe, Australia, and New Zealand. In October 2013, CTI reached agreement with the FDA on a special protocol assessment for the trial, a written agreement between CTI and the FDA regarding the planned design, endpoints, and statistical analysis approach of the trial to be used in support of a potential new drug application.

Under the special protocol assessment, the trial will have two primary endpoints. The first is the percentage of patients achieving a 35% or greater reduction in spleen volume, measured by MRI or CT scan from baseline to 24 weeks of treatment.

The second primary endpoint is the percentage of patients achieving a total symptom score reduction of 50% or greater using 6 key symptoms, as measured by the modified Myeloproliferative Neoplasm Symptom Assessment (MPN-SAF TSS 2.0) diary from baseline to 24 weeks.

More details on the PERSIST-1 and PERSIST-2 trials can be found at www.clinicaltrials.gov.

The effectiveness of influenza vaccine is recognized to vary widely from season to season. At least two factors are critical for determining the likelihood that flu vaccine will be successful in preventing illness.

First, the demographics of who is being immunized (primarily age and presence of comorbidity) and second, the "match" between the circulating flu viruses and that year’s flu vaccine. When the flu vaccine is a poor match with circulating viruses, less benefit from flu vaccination will be observed; in years when the "match" between vaccine and circulating virus is good, substantial reduction in influenza respiratory illness in children and adults is observed. Recently, a second influenza B antigen has been added (creating quadrivalent vaccines) to improve the match with influenza B strains that may circulate in the community.

In February 2014, the Centers for Disease Control and Prevention reported midseason vaccine effectiveness estimates (MMWR 2014 Feb 21;63:137-42).

The major circulating virus was influenza A "2009 H1N1" virus and the "match" between vaccine strains and circulating strains was considered good. The CDC’s midseason vaccine effectiveness estimate was 61% for all age groups (95% confidence interval, 52%-68%), reinforcing the value of influenza vaccine for disease prevention in both children and adults. Flu vaccine reduced the risk of seeking medical attention for flulike illness by 60% for both children and adults.

Another factor that may determine the effectiveness of influenza vaccine in children is whether the individual receives live attenuated influenza vaccine (LAIV) or trivalent or quadrivalent inactivated influenza vaccine (IIV). The CDC has been considering the question "should LAIV be recommended preferentially over IIV in healthy children 2-8 years of age?" based on data from a limited number of studies. Canada, United Kingdom, Israel, and Germany have each expressed a preference for LAIV in their recent recommendations. The CDC working group evaluated published studies primarily restricted to those focused on healthy children, those with both LAIV and IIV cohorts, those studying the U.S. licensed and similar vaccines, and those in English. Their literature review identified five randomized trials and five additional observational studies. Lab-confirmed influenza in symptomatic children was the primary outcome; influenza related mortality and hospitalization also were considered.

The efficacy of LAIV was originally established in four randomized, placebo-controlled clinical trials. Each study was completed over two influenza seasons.

In the Belshe study (N. Engl. J. Med. 1998;338:1405-12), the efficacy compared with placebo was 93% in the first season and 100% in the second (after revaccination).

In a second study (Pediatrics 2006;118:2298-312), efficacy compared to placebo was 85% in the first season and 89% in the second (after revaccination).

Subsequently, randomized studies comparing LAIV with IIV in children younger than 8 years of age demonstrating the relative benefits of LAIV were reported (N. Engl. J. Med. 2007;356:685-96; Pediatr. Infect. Dis. J. 2006 ;25:870-9). A reduction greater than or equal to 50% in laboratory-confirmed influenza cases in the LAIV cohorts compared with the trivalent inactivated vaccine groups was observed. Greater efficacy was reported both in groups that were influenza vaccine naive as well as those with prior immunization. No reductions in hospitalization and medically-attended acute respiratory illness were reported for the LAIV cohorts; however, the quality of the data was judged to be less robust than for laboratory-confirmed disease. For children aged 9-18 years, no differences in laboratory-confirmed influenza were reported.

The mechanism for improved efficacy of LAIV in young children (2-8 years) is largely unknown. LAIV may elicit long-lasting and broader humoral and cellular responses that more closely resembles natural immunity. It also has been hypothesized that LAIV is more immunogenic than IIV as a priming vaccine, and IIV is more effective in boosting preexisting immunity. It is possible that is one explanation for why LAIV is more effective in young children, and that no differences are observed in older children and adults. It also has been suggested that LAIV may elicit an antibody that is more broadly protective against mismatched influenza strains.

In June, the Advisory Committee on Immunization Practices (ACIP) proposed new recommendations regarding the use of LAIV and IIV for young healthy children. ACIP affirmed that both LAIV and IIV are effective in prevention of influenza in children, but recommended that LAIV be used for healthy children aged 2-8 years when both vaccines are available and there are no contraindications or precautions to its use. When LAIV is not immediately available, IIV should be used. Vaccination should not be delayed to procure LAIV.

ACIP restated previous contraindications and precautions to administration of LAIV. Those with contraindications to LAIV should receive inactivated vaccine. These include:

• Children less than 2 years of age and adults older than 49 years of age.

• Children aged 2-17 years receiving aspirin, persons with allergic reactions to vaccine or vaccine components, pregnant women, immunosuppressed persons, and persons with egg allergy.

• Children aged 2-4 years who have had a wheezing episode noted in the medical record or whose parents report that a health care provider informed them of wheezing or asthma within the last 12 months.

• Individuals who have taken antiviral medications within the previous 48 hours.

Administration to children less than 8 years of age with chronic medical conditions (specifically those associated with increased risk of influenza complications) is considered a precaution as safety has not been established.

Immunization for all children beginning at 6 months of age is still the essential message. However, when both LAIV and IIV (trivalent [TIV] or quadrivalent inactivated influenza vaccines [QIV]) are available, the advisory committee recommended LAIV as a preference in healthy children aged 2-8 years. If only TIV or QIV is available, administration of either one is recommended as delays in receipt are of greater concern than are the differences in vaccine formulations. This recommendation, if approved by the CDC director, will not be official until it is published in the 2014-2015 influenza prevention and control recommendations in the MMWR. In anticipation of this new recommendation, the manufacturer has stated that it will be producing 18 million doses of quadrivalent LAIV for the U.S. market for the 2014-2015 season, up from the 13 million it produced last season. More information when available also will be posted on the CDC influenza website and the American Academy of Pediatrics website.

Dr. Pelton is chief of pediatric infectious disease and coordinator of the maternal-child HIV program at Boston Medical Center. He said that he had no relevant financial disclosures.

The effectiveness of influenza vaccine is recognized to vary widely from season to season. At least two factors are critical for determining the likelihood that flu vaccine will be successful in preventing illness.

First, the demographics of who is being immunized (primarily age and presence of comorbidity) and second, the "match" between the circulating flu viruses and that year’s flu vaccine. When the flu vaccine is a poor match with circulating viruses, less benefit from flu vaccination will be observed; in years when the "match" between vaccine and circulating virus is good, substantial reduction in influenza respiratory illness in children and adults is observed. Recently, a second influenza B antigen has been added (creating quadrivalent vaccines) to improve the match with influenza B strains that may circulate in the community.

In February 2014, the Centers for Disease Control and Prevention reported midseason vaccine effectiveness estimates (MMWR 2014 Feb 21;63:137-42).

The major circulating virus was influenza A "2009 H1N1" virus and the "match" between vaccine strains and circulating strains was considered good. The CDC’s midseason vaccine effectiveness estimate was 61% for all age groups (95% confidence interval, 52%-68%), reinforcing the value of influenza vaccine for disease prevention in both children and adults. Flu vaccine reduced the risk of seeking medical attention for flulike illness by 60% for both children and adults.

Another factor that may determine the effectiveness of influenza vaccine in children is whether the individual receives live attenuated influenza vaccine (LAIV) or trivalent or quadrivalent inactivated influenza vaccine (IIV). The CDC has been considering the question "should LAIV be recommended preferentially over IIV in healthy children 2-8 years of age?" based on data from a limited number of studies. Canada, United Kingdom, Israel, and Germany have each expressed a preference for LAIV in their recent recommendations. The CDC working group evaluated published studies primarily restricted to those focused on healthy children, those with both LAIV and IIV cohorts, those studying the U.S. licensed and similar vaccines, and those in English. Their literature review identified five randomized trials and five additional observational studies. Lab-confirmed influenza in symptomatic children was the primary outcome; influenza related mortality and hospitalization also were considered.

The efficacy of LAIV was originally established in four randomized, placebo-controlled clinical trials. Each study was completed over two influenza seasons.

In the Belshe study (N. Engl. J. Med. 1998;338:1405-12), the efficacy compared with placebo was 93% in the first season and 100% in the second (after revaccination).

In a second study (Pediatrics 2006;118:2298-312), efficacy compared to placebo was 85% in the first season and 89% in the second (after revaccination).

Subsequently, randomized studies comparing LAIV with IIV in children younger than 8 years of age demonstrating the relative benefits of LAIV were reported (N. Engl. J. Med. 2007;356:685-96; Pediatr. Infect. Dis. J. 2006 ;25:870-9). A reduction greater than or equal to 50% in laboratory-confirmed influenza cases in the LAIV cohorts compared with the trivalent inactivated vaccine groups was observed. Greater efficacy was reported both in groups that were influenza vaccine naive as well as those with prior immunization. No reductions in hospitalization and medically-attended acute respiratory illness were reported for the LAIV cohorts; however, the quality of the data was judged to be less robust than for laboratory-confirmed disease. For children aged 9-18 years, no differences in laboratory-confirmed influenza were reported.

The mechanism for improved efficacy of LAIV in young children (2-8 years) is largely unknown. LAIV may elicit long-lasting and broader humoral and cellular responses that more closely resembles natural immunity. It also has been hypothesized that LAIV is more immunogenic than IIV as a priming vaccine, and IIV is more effective in boosting preexisting immunity. It is possible that is one explanation for why LAIV is more effective in young children, and that no differences are observed in older children and adults. It also has been suggested that LAIV may elicit an antibody that is more broadly protective against mismatched influenza strains.

In June, the Advisory Committee on Immunization Practices (ACIP) proposed new recommendations regarding the use of LAIV and IIV for young healthy children. ACIP affirmed that both LAIV and IIV are effective in prevention of influenza in children, but recommended that LAIV be used for healthy children aged 2-8 years when both vaccines are available and there are no contraindications or precautions to its use. When LAIV is not immediately available, IIV should be used. Vaccination should not be delayed to procure LAIV.

ACIP restated previous contraindications and precautions to administration of LAIV. Those with contraindications to LAIV should receive inactivated vaccine. These include:

• Children less than 2 years of age and adults older than 49 years of age.

• Children aged 2-17 years receiving aspirin, persons with allergic reactions to vaccine or vaccine components, pregnant women, immunosuppressed persons, and persons with egg allergy.

• Children aged 2-4 years who have had a wheezing episode noted in the medical record or whose parents report that a health care provider informed them of wheezing or asthma within the last 12 months.

• Individuals who have taken antiviral medications within the previous 48 hours.

Administration to children less than 8 years of age with chronic medical conditions (specifically those associated with increased risk of influenza complications) is considered a precaution as safety has not been established.

Immunization for all children beginning at 6 months of age is still the essential message. However, when both LAIV and IIV (trivalent [TIV] or quadrivalent inactivated influenza vaccines [QIV]) are available, the advisory committee recommended LAIV as a preference in healthy children aged 2-8 years. If only TIV or QIV is available, administration of either one is recommended as delays in receipt are of greater concern than are the differences in vaccine formulations. This recommendation, if approved by the CDC director, will not be official until it is published in the 2014-2015 influenza prevention and control recommendations in the MMWR. In anticipation of this new recommendation, the manufacturer has stated that it will be producing 18 million doses of quadrivalent LAIV for the U.S. market for the 2014-2015 season, up from the 13 million it produced last season. More information when available also will be posted on the CDC influenza website and the American Academy of Pediatrics website.

Dr. Pelton is chief of pediatric infectious disease and coordinator of the maternal-child HIV program at Boston Medical Center. He said that he had no relevant financial disclosures.

The effectiveness of influenza vaccine is recognized to vary widely from season to season. At least two factors are critical for determining the likelihood that flu vaccine will be successful in preventing illness.

First, the demographics of who is being immunized (primarily age and presence of comorbidity) and second, the "match" between the circulating flu viruses and that year’s flu vaccine. When the flu vaccine is a poor match with circulating viruses, less benefit from flu vaccination will be observed; in years when the "match" between vaccine and circulating virus is good, substantial reduction in influenza respiratory illness in children and adults is observed. Recently, a second influenza B antigen has been added (creating quadrivalent vaccines) to improve the match with influenza B strains that may circulate in the community.

In February 2014, the Centers for Disease Control and Prevention reported midseason vaccine effectiveness estimates (MMWR 2014 Feb 21;63:137-42).

The major circulating virus was influenza A "2009 H1N1" virus and the "match" between vaccine strains and circulating strains was considered good. The CDC’s midseason vaccine effectiveness estimate was 61% for all age groups (95% confidence interval, 52%-68%), reinforcing the value of influenza vaccine for disease prevention in both children and adults. Flu vaccine reduced the risk of seeking medical attention for flulike illness by 60% for both children and adults.

Another factor that may determine the effectiveness of influenza vaccine in children is whether the individual receives live attenuated influenza vaccine (LAIV) or trivalent or quadrivalent inactivated influenza vaccine (IIV). The CDC has been considering the question "should LAIV be recommended preferentially over IIV in healthy children 2-8 years of age?" based on data from a limited number of studies. Canada, United Kingdom, Israel, and Germany have each expressed a preference for LAIV in their recent recommendations. The CDC working group evaluated published studies primarily restricted to those focused on healthy children, those with both LAIV and IIV cohorts, those studying the U.S. licensed and similar vaccines, and those in English. Their literature review identified five randomized trials and five additional observational studies. Lab-confirmed influenza in symptomatic children was the primary outcome; influenza related mortality and hospitalization also were considered.

The efficacy of LAIV was originally established in four randomized, placebo-controlled clinical trials. Each study was completed over two influenza seasons.

In the Belshe study (N. Engl. J. Med. 1998;338:1405-12), the efficacy compared with placebo was 93% in the first season and 100% in the second (after revaccination).

In a second study (Pediatrics 2006;118:2298-312), efficacy compared to placebo was 85% in the first season and 89% in the second (after revaccination).

Subsequently, randomized studies comparing LAIV with IIV in children younger than 8 years of age demonstrating the relative benefits of LAIV were reported (N. Engl. J. Med. 2007;356:685-96; Pediatr. Infect. Dis. J. 2006 ;25:870-9). A reduction greater than or equal to 50% in laboratory-confirmed influenza cases in the LAIV cohorts compared with the trivalent inactivated vaccine groups was observed. Greater efficacy was reported both in groups that were influenza vaccine naive as well as those with prior immunization. No reductions in hospitalization and medically-attended acute respiratory illness were reported for the LAIV cohorts; however, the quality of the data was judged to be less robust than for laboratory-confirmed disease. For children aged 9-18 years, no differences in laboratory-confirmed influenza were reported.

The mechanism for improved efficacy of LAIV in young children (2-8 years) is largely unknown. LAIV may elicit long-lasting and broader humoral and cellular responses that more closely resembles natural immunity. It also has been hypothesized that LAIV is more immunogenic than IIV as a priming vaccine, and IIV is more effective in boosting preexisting immunity. It is possible that is one explanation for why LAIV is more effective in young children, and that no differences are observed in older children and adults. It also has been suggested that LAIV may elicit an antibody that is more broadly protective against mismatched influenza strains.

In June, the Advisory Committee on Immunization Practices (ACIP) proposed new recommendations regarding the use of LAIV and IIV for young healthy children. ACIP affirmed that both LAIV and IIV are effective in prevention of influenza in children, but recommended that LAIV be used for healthy children aged 2-8 years when both vaccines are available and there are no contraindications or precautions to its use. When LAIV is not immediately available, IIV should be used. Vaccination should not be delayed to procure LAIV.

ACIP restated previous contraindications and precautions to administration of LAIV. Those with contraindications to LAIV should receive inactivated vaccine. These include:

• Children less than 2 years of age and adults older than 49 years of age.

• Children aged 2-17 years receiving aspirin, persons with allergic reactions to vaccine or vaccine components, pregnant women, immunosuppressed persons, and persons with egg allergy.

• Children aged 2-4 years who have had a wheezing episode noted in the medical record or whose parents report that a health care provider informed them of wheezing or asthma within the last 12 months.

• Individuals who have taken antiviral medications within the previous 48 hours.

Administration to children less than 8 years of age with chronic medical conditions (specifically those associated with increased risk of influenza complications) is considered a precaution as safety has not been established.

Immunization for all children beginning at 6 months of age is still the essential message. However, when both LAIV and IIV (trivalent [TIV] or quadrivalent inactivated influenza vaccines [QIV]) are available, the advisory committee recommended LAIV as a preference in healthy children aged 2-8 years. If only TIV or QIV is available, administration of either one is recommended as delays in receipt are of greater concern than are the differences in vaccine formulations. This recommendation, if approved by the CDC director, will not be official until it is published in the 2014-2015 influenza prevention and control recommendations in the MMWR. In anticipation of this new recommendation, the manufacturer has stated that it will be producing 18 million doses of quadrivalent LAIV for the U.S. market for the 2014-2015 season, up from the 13 million it produced last season. More information when available also will be posted on the CDC influenza website and the American Academy of Pediatrics website.

Dr. Pelton is chief of pediatric infectious disease and coordinator of the maternal-child HIV program at Boston Medical Center. He said that he had no relevant financial disclosures.

A researchers examining

a tumor sample in a test tube

Credit: Rhoda Baer

Defining cancers by molecular criteria rather than their tissue of origin can provide patients with more accurate diagnoses, researchers have reported in Cell.

The group analyzed the molecular characteristics of more than 3500 samples of 12 different cancers and reclassified them according to the new information.

For 5 of the cancer types, including acute myeloid leukemia (AML), the molecular classification largely matched the tissue-of-origin classification.

For the remaining malignancies, that was not the case.

“This genomic study not only challenges our existing system of classifying cancers based on tissue type, but also provides a massive new data resource for further exploration, as well as a comprehensive list of the molecular features distinguishing each of the newly described cancer classes,” said study author Christopher Benz, MD, of the University of California, San Francisco.

The researchers said each molecular subtype they identified may reflect tumors arising from distinct cell types. For example, the data showed a marked difference between cancers of epithelial and non-epithelial origins.

“We think the subtypes reflect, primarily, the cell of origin,” said study author Joshua Stuart, PhD, of the University of California, Santa Cruz.

“Another factor is the nature of the genomic lesion, and third is the microenvironment of the cell and how surrounding cells influence it. We are disentangling the signals from these different factors so we can gauge each one for its prognostic power.”

Identifying molecular subtypes

The researchers performed an integrative analysis using 5 genome-wide platforms and 1 proteomic platform on 3527 specimens from 12 cancer types.

This included AML, glioblastoma multiforme, serous ovarian carcinoma, colon and rectal adenocarcinomas, lung squamous cell carcinoma, breast cancer, endometrial cancer, renal cell carcinoma, bladder urothelial adenocarcinoma, lung adenocarcinoma, and head and neck squamous cell carcinoma.

The group’s analyses allowed them to classify these cancer types into 11 major cellular/molecular subtypes. Two of the initial 13 subtypes (numbers 11 and 12) were eliminated from further analysis because they included fewer than 10 samples.

Five of the classification types—C5-renal cell carcinoma, C6-endometrial cancer, C9-serous ovarian carcinoma, C10-glioblastoma multiforme, and C13-AML—showed near 1-to-1 relationships with the tissue site of origin. However, there were a few cases of reclassification here and there, such as a case of breast cancer that fell in the AML subtype.

Another subtype stayed pretty true to its tissues of origin. C7-colon adenocarcinoma/rectal adenocarcinoma was composed mainly of colon and rectal adenocarcinomas but also included a case of endometrial cancer.

The C1-lung adenocarcinoma-enriched subtype was predominantly composed of non-small cell lung adenocarcinoma samples. But it also included cases of bladder cancer, breast cancer, colon adenocarcinoma, glioblastoma multiforme, head and neck squamous cell carcinoma, renal cell carcinoma, lung squamous cell carcinoma , serous ovarian carcinoma, and endometrial cancer.

The C2-squamous-like subtype consisted largely of head and neck squamous cell carcinoma and lung squamous cell carcinoma but also included bladder urothelial adenocarcinoma and breast cancer.

Breast cancers were further divided into the C3-breast cancer/luminal subtype and the C4-breast cancer/basal subtype. The C4 subtype also included lung adenocarcinoma and lung squamous cell carcinoma.

The researchers noted that breast cancers were present in 7 of the subtype classifications. And while this study confirmed known differences between the subtypes of breast cancer, the team was surprised to discover that basal-like breast cancers actually constitute their own cancer class.

“Even though these basal-like cancers arise in the breast, on the molecular level, they have more in common with ovarian cancers and cancers of squamous-cell origin than with other subtypes of breast cancer,” said study author Christina Yau, PhD, of the University of California, San Francisco.

Like breast cancers, bladder cancers were present in 7 of the subtype classifications. There were 1 or 2 cases in C5, C10, C11, and C12.  But most bladder cancer samples fell into 1 of 3 categories: C1-lung adenocarcinoma-enriched, C2-squamous-like, and C8-bladder urothelial adenocarcinoma.

Although the C8-bladder urothelial adenocarcinoma subtype consisted largely of bladder cancer, it also included breast cancer, head and neck squamous cell carcinoma, lung adenocarcinoma, and lung squamous cell carcinoma.

These findings may help explain why patients with bladder cancer “often respond very differently when treated with the same systemic therapy for their seemingly identical cancer type,” Dr Benz said.

In fact, the researchers found the bladder cancers that clustered with other tumor types had a worse prognosis.

Next steps

The researchers noted that follow-up studies are needed to validate these findings, but this analysis lays the groundwork for classifying tumors into molecularly defined subtypes. The new classification scheme could be used to enroll patients in clinical trials and could lead to different treatment options based on molecular subtypes.

“We can now say what the telltale signatures of the subtypes are, so you can classify a patient’s tumor just based on the gene expression data, or just based on mutation data, if that’s what you have,” Dr Stuart said. “Having a molecular map like this could help get a patient into the right clinical trial.”

The researchers believe the percentage of tumors that should be reclassified based on molecular signatures is likely to grow as more samples and tumor types are analyzed. This study suggested that 1 in 10 cancers could be reclassified in clinically meaningful ways, but the researchers said their next analysis will include 21 tumor types instead of 12.

“We’re just appreciating the tip of the iceberg when considering the potential of this multiplatform type of genomic analysis,” Dr Benz said. “It could be that as many as 30% or 50% of cancers need to be reclassified.”

The data sets and results from this study have been made available to other researchers through the Synapse website.

A researchers examining

a tumor sample in a test tube

Credit: Rhoda Baer

Defining cancers by molecular criteria rather than their tissue of origin can provide patients with more accurate diagnoses, researchers have reported in Cell.

The group analyzed the molecular characteristics of more than 3500 samples of 12 different cancers and reclassified them according to the new information.

For 5 of the cancer types, including acute myeloid leukemia (AML), the molecular classification largely matched the tissue-of-origin classification.

For the remaining malignancies, that was not the case.

“This genomic study not only challenges our existing system of classifying cancers based on tissue type, but also provides a massive new data resource for further exploration, as well as a comprehensive list of the molecular features distinguishing each of the newly described cancer classes,” said study author Christopher Benz, MD, of the University of California, San Francisco.

The researchers said each molecular subtype they identified may reflect tumors arising from distinct cell types. For example, the data showed a marked difference between cancers of epithelial and non-epithelial origins.

“We think the subtypes reflect, primarily, the cell of origin,” said study author Joshua Stuart, PhD, of the University of California, Santa Cruz.

“Another factor is the nature of the genomic lesion, and third is the microenvironment of the cell and how surrounding cells influence it. We are disentangling the signals from these different factors so we can gauge each one for its prognostic power.”

Identifying molecular subtypes

The researchers performed an integrative analysis using 5 genome-wide platforms and 1 proteomic platform on 3527 specimens from 12 cancer types.

This included AML, glioblastoma multiforme, serous ovarian carcinoma, colon and rectal adenocarcinomas, lung squamous cell carcinoma, breast cancer, endometrial cancer, renal cell carcinoma, bladder urothelial adenocarcinoma, lung adenocarcinoma, and head and neck squamous cell carcinoma.

The group’s analyses allowed them to classify these cancer types into 11 major cellular/molecular subtypes. Two of the initial 13 subtypes (numbers 11 and 12) were eliminated from further analysis because they included fewer than 10 samples.

Five of the classification types—C5-renal cell carcinoma, C6-endometrial cancer, C9-serous ovarian carcinoma, C10-glioblastoma multiforme, and C13-AML—showed near 1-to-1 relationships with the tissue site of origin. However, there were a few cases of reclassification here and there, such as a case of breast cancer that fell in the AML subtype.

Another subtype stayed pretty true to its tissues of origin. C7-colon adenocarcinoma/rectal adenocarcinoma was composed mainly of colon and rectal adenocarcinomas but also included a case of endometrial cancer.

The C1-lung adenocarcinoma-enriched subtype was predominantly composed of non-small cell lung adenocarcinoma samples. But it also included cases of bladder cancer, breast cancer, colon adenocarcinoma, glioblastoma multiforme, head and neck squamous cell carcinoma, renal cell carcinoma, lung squamous cell carcinoma , serous ovarian carcinoma, and endometrial cancer.

The C2-squamous-like subtype consisted largely of head and neck squamous cell carcinoma and lung squamous cell carcinoma but also included bladder urothelial adenocarcinoma and breast cancer.

Breast cancers were further divided into the C3-breast cancer/luminal subtype and the C4-breast cancer/basal subtype. The C4 subtype also included lung adenocarcinoma and lung squamous cell carcinoma.

The researchers noted that breast cancers were present in 7 of the subtype classifications. And while this study confirmed known differences between the subtypes of breast cancer, the team was surprised to discover that basal-like breast cancers actually constitute their own cancer class.

“Even though these basal-like cancers arise in the breast, on the molecular level, they have more in common with ovarian cancers and cancers of squamous-cell origin than with other subtypes of breast cancer,” said study author Christina Yau, PhD, of the University of California, San Francisco.

Like breast cancers, bladder cancers were present in 7 of the subtype classifications. There were 1 or 2 cases in C5, C10, C11, and C12.  But most bladder cancer samples fell into 1 of 3 categories: C1-lung adenocarcinoma-enriched, C2-squamous-like, and C8-bladder urothelial adenocarcinoma.

Although the C8-bladder urothelial adenocarcinoma subtype consisted largely of bladder cancer, it also included breast cancer, head and neck squamous cell carcinoma, lung adenocarcinoma, and lung squamous cell carcinoma.

These findings may help explain why patients with bladder cancer “often respond very differently when treated with the same systemic therapy for their seemingly identical cancer type,” Dr Benz said.

In fact, the researchers found the bladder cancers that clustered with other tumor types had a worse prognosis.

Next steps

The researchers noted that follow-up studies are needed to validate these findings, but this analysis lays the groundwork for classifying tumors into molecularly defined subtypes. The new classification scheme could be used to enroll patients in clinical trials and could lead to different treatment options based on molecular subtypes.

“We can now say what the telltale signatures of the subtypes are, so you can classify a patient’s tumor just based on the gene expression data, or just based on mutation data, if that’s what you have,” Dr Stuart said. “Having a molecular map like this could help get a patient into the right clinical trial.”

The researchers believe the percentage of tumors that should be reclassified based on molecular signatures is likely to grow as more samples and tumor types are analyzed. This study suggested that 1 in 10 cancers could be reclassified in clinically meaningful ways, but the researchers said their next analysis will include 21 tumor types instead of 12.

“We’re just appreciating the tip of the iceberg when considering the potential of this multiplatform type of genomic analysis,” Dr Benz said. “It could be that as many as 30% or 50% of cancers need to be reclassified.”

The data sets and results from this study have been made available to other researchers through the Synapse website.

A researchers examining

a tumor sample in a test tube

Credit: Rhoda Baer

Defining cancers by molecular criteria rather than their tissue of origin can provide patients with more accurate diagnoses, researchers have reported in Cell.

The group analyzed the molecular characteristics of more than 3500 samples of 12 different cancers and reclassified them according to the new information.

For 5 of the cancer types, including acute myeloid leukemia (AML), the molecular classification largely matched the tissue-of-origin classification.

For the remaining malignancies, that was not the case.

“This genomic study not only challenges our existing system of classifying cancers based on tissue type, but also provides a massive new data resource for further exploration, as well as a comprehensive list of the molecular features distinguishing each of the newly described cancer classes,” said study author Christopher Benz, MD, of the University of California, San Francisco.

The researchers said each molecular subtype they identified may reflect tumors arising from distinct cell types. For example, the data showed a marked difference between cancers of epithelial and non-epithelial origins.

“We think the subtypes reflect, primarily, the cell of origin,” said study author Joshua Stuart, PhD, of the University of California, Santa Cruz.

“Another factor is the nature of the genomic lesion, and third is the microenvironment of the cell and how surrounding cells influence it. We are disentangling the signals from these different factors so we can gauge each one for its prognostic power.”

Identifying molecular subtypes

The researchers performed an integrative analysis using 5 genome-wide platforms and 1 proteomic platform on 3527 specimens from 12 cancer types.

This included AML, glioblastoma multiforme, serous ovarian carcinoma, colon and rectal adenocarcinomas, lung squamous cell carcinoma, breast cancer, endometrial cancer, renal cell carcinoma, bladder urothelial adenocarcinoma, lung adenocarcinoma, and head and neck squamous cell carcinoma.

The group’s analyses allowed them to classify these cancer types into 11 major cellular/molecular subtypes. Two of the initial 13 subtypes (numbers 11 and 12) were eliminated from further analysis because they included fewer than 10 samples.

Five of the classification types—C5-renal cell carcinoma, C6-endometrial cancer, C9-serous ovarian carcinoma, C10-glioblastoma multiforme, and C13-AML—showed near 1-to-1 relationships with the tissue site of origin. However, there were a few cases of reclassification here and there, such as a case of breast cancer that fell in the AML subtype.

Another subtype stayed pretty true to its tissues of origin. C7-colon adenocarcinoma/rectal adenocarcinoma was composed mainly of colon and rectal adenocarcinomas but also included a case of endometrial cancer.

The C1-lung adenocarcinoma-enriched subtype was predominantly composed of non-small cell lung adenocarcinoma samples. But it also included cases of bladder cancer, breast cancer, colon adenocarcinoma, glioblastoma multiforme, head and neck squamous cell carcinoma, renal cell carcinoma, lung squamous cell carcinoma , serous ovarian carcinoma, and endometrial cancer.

The C2-squamous-like subtype consisted largely of head and neck squamous cell carcinoma and lung squamous cell carcinoma but also included bladder urothelial adenocarcinoma and breast cancer.

Breast cancers were further divided into the C3-breast cancer/luminal subtype and the C4-breast cancer/basal subtype. The C4 subtype also included lung adenocarcinoma and lung squamous cell carcinoma.

The researchers noted that breast cancers were present in 7 of the subtype classifications. And while this study confirmed known differences between the subtypes of breast cancer, the team was surprised to discover that basal-like breast cancers actually constitute their own cancer class.

“Even though these basal-like cancers arise in the breast, on the molecular level, they have more in common with ovarian cancers and cancers of squamous-cell origin than with other subtypes of breast cancer,” said study author Christina Yau, PhD, of the University of California, San Francisco.

Like breast cancers, bladder cancers were present in 7 of the subtype classifications. There were 1 or 2 cases in C5, C10, C11, and C12.  But most bladder cancer samples fell into 1 of 3 categories: C1-lung adenocarcinoma-enriched, C2-squamous-like, and C8-bladder urothelial adenocarcinoma.

Although the C8-bladder urothelial adenocarcinoma subtype consisted largely of bladder cancer, it also included breast cancer, head and neck squamous cell carcinoma, lung adenocarcinoma, and lung squamous cell carcinoma.

These findings may help explain why patients with bladder cancer “often respond very differently when treated with the same systemic therapy for their seemingly identical cancer type,” Dr Benz said.

In fact, the researchers found the bladder cancers that clustered with other tumor types had a worse prognosis.

Next steps

The researchers noted that follow-up studies are needed to validate these findings, but this analysis lays the groundwork for classifying tumors into molecularly defined subtypes. The new classification scheme could be used to enroll patients in clinical trials and could lead to different treatment options based on molecular subtypes.

“We can now say what the telltale signatures of the subtypes are, so you can classify a patient’s tumor just based on the gene expression data, or just based on mutation data, if that’s what you have,” Dr Stuart said. “Having a molecular map like this could help get a patient into the right clinical trial.”

The researchers believe the percentage of tumors that should be reclassified based on molecular signatures is likely to grow as more samples and tumor types are analyzed. This study suggested that 1 in 10 cancers could be reclassified in clinically meaningful ways, but the researchers said their next analysis will include 21 tumor types instead of 12.

“We’re just appreciating the tip of the iceberg when considering the potential of this multiplatform type of genomic analysis,” Dr Benz said. “It could be that as many as 30% or 50% of cancers need to be reclassified.”

The data sets and results from this study have been made available to other researchers through the Synapse website.