AACR Annual Meeting 2015

CLL cells

PHILADELPHIA—A DNA-dependent protein kinase (DNA-PK) inhibitor can sensitize chronic lymphocytic leukemia (CLL) cells to chemotherapy, according to

preclinical research.

The inhibitor, NDD0004, sensitized CLL cells—even those from patients with high-risk cytogenetics—to treatment with mitoxantrone.

However, not all CLL samples were sensitive to treatment, so researchers are now trying to determine which patients might derive benefit from DNA-PK inhibitors.

Gesa Junge, a PhD student at Newcastle University in the UK, and her colleagues conducted this research and presented the results at the AACR Annual Meeting 2015 (abstract 3624*). The work was supported by AstraZeneca.

The researchers’ goal was to validate that DNA-PK inhibition is a valid approach to chemosensitization in CLL. So the team tested NU7441—a compound that inhibits DNA-PK and PI3 kinase—and NDD0004—a more selective DNA-PK inhibitor.

The team isolated CLL cells from patients’ peripheral blood, cultured the cells, and treated them with mitoxantrone and/or 1μM of NDD0004 or 1μM of NU7441.

Junge and her colleagues found that NDD0004 sensitized cells to mitoxantrone more effectively than NU7441. Sensitization was 202-fold higher with NDD004 plus mitoxantrone than with mitoxantrone alone and 69-fold higher with NU7441 plus mitoxantrone than with mitoxantrone alone (P=0.02).

However, sensitization varied between CLL samples, and the researchers have yet to determine why. Their experiments showed that variability was not a result of DNA-PK levels.

Still, the team found that CLL cells from patients with poor prognostic markers were sensitive to DNA-PK inhibition.

Sensitization with NU7441 plus mitoxantrone was 69-fold higher than mitoxantrone alone in CLL samples with del(13q), 25-fold higher in samples with del(11q), 12-fold higher in samples with TP53 mutation, and 16-fold higher in samples with ATM dysfunction.

Sensitization with NDD0004 plus mitoxantrone was 201-fold higher than mitoxantrone alone in CLL samples with del(13q), 314-fold higher in samples with del(11q), 27-fold higher in samples with TP53 mutation, and 18-fold higher in samples with ATM dysfunction.

To confirm that sensitization was a result of DNA-PK inhibition, Junge and her colleagues tested NDD0004 in an isogenic pair of DNA-PK-deficient and DNA-PK-proficient HCT116 cells. They found that HCT116 cells lacking DNA-PK were not sensitive to NDD0004, but cells with DNA-PK were sensitive.

The researchers also investigated the mechanism of NDD0004. Their results suggest the drug works by inhibiting the repair of DNA double-strand breaks.

“What we think is happening is that we are inducing DNA damage with mitoxantrone, and that gets repaired by 24 hours,” Junge said. “But if the DNA-PK inhibitor is there, the damage persists, and that seems to translate quite nicely into an apoptosis response.”

To further this research, Junge and her colleagues are hoping to identify biomarkers that can help them determine which CLL patients are likely to respond to DNA-PK inhibitors.

*Information in the abstract differs from that presented at the meeting.

CLL cells

PHILADELPHIA—A DNA-dependent protein kinase (DNA-PK) inhibitor can sensitize chronic lymphocytic leukemia (CLL) cells to chemotherapy, according to

preclinical research.

The inhibitor, NDD0004, sensitized CLL cells—even those from patients with high-risk cytogenetics—to treatment with mitoxantrone.

However, not all CLL samples were sensitive to treatment, so researchers are now trying to determine which patients might derive benefit from DNA-PK inhibitors.

Gesa Junge, a PhD student at Newcastle University in the UK, and her colleagues conducted this research and presented the results at the AACR Annual Meeting 2015 (abstract 3624*). The work was supported by AstraZeneca.

The researchers’ goal was to validate that DNA-PK inhibition is a valid approach to chemosensitization in CLL. So the team tested NU7441—a compound that inhibits DNA-PK and PI3 kinase—and NDD0004—a more selective DNA-PK inhibitor.

The team isolated CLL cells from patients’ peripheral blood, cultured the cells, and treated them with mitoxantrone and/or 1μM of NDD0004 or 1μM of NU7441.

Junge and her colleagues found that NDD0004 sensitized cells to mitoxantrone more effectively than NU7441. Sensitization was 202-fold higher with NDD004 plus mitoxantrone than with mitoxantrone alone and 69-fold higher with NU7441 plus mitoxantrone than with mitoxantrone alone (P=0.02).

However, sensitization varied between CLL samples, and the researchers have yet to determine why. Their experiments showed that variability was not a result of DNA-PK levels.

Still, the team found that CLL cells from patients with poor prognostic markers were sensitive to DNA-PK inhibition.

Sensitization with NU7441 plus mitoxantrone was 69-fold higher than mitoxantrone alone in CLL samples with del(13q), 25-fold higher in samples with del(11q), 12-fold higher in samples with TP53 mutation, and 16-fold higher in samples with ATM dysfunction.

Sensitization with NDD0004 plus mitoxantrone was 201-fold higher than mitoxantrone alone in CLL samples with del(13q), 314-fold higher in samples with del(11q), 27-fold higher in samples with TP53 mutation, and 18-fold higher in samples with ATM dysfunction.

To confirm that sensitization was a result of DNA-PK inhibition, Junge and her colleagues tested NDD0004 in an isogenic pair of DNA-PK-deficient and DNA-PK-proficient HCT116 cells. They found that HCT116 cells lacking DNA-PK were not sensitive to NDD0004, but cells with DNA-PK were sensitive.

The researchers also investigated the mechanism of NDD0004. Their results suggest the drug works by inhibiting the repair of DNA double-strand breaks.

“What we think is happening is that we are inducing DNA damage with mitoxantrone, and that gets repaired by 24 hours,” Junge said. “But if the DNA-PK inhibitor is there, the damage persists, and that seems to translate quite nicely into an apoptosis response.”

To further this research, Junge and her colleagues are hoping to identify biomarkers that can help them determine which CLL patients are likely to respond to DNA-PK inhibitors.

*Information in the abstract differs from that presented at the meeting.

CLL cells

PHILADELPHIA—A DNA-dependent protein kinase (DNA-PK) inhibitor can sensitize chronic lymphocytic leukemia (CLL) cells to chemotherapy, according to

preclinical research.

The inhibitor, NDD0004, sensitized CLL cells—even those from patients with high-risk cytogenetics—to treatment with mitoxantrone.

However, not all CLL samples were sensitive to treatment, so researchers are now trying to determine which patients might derive benefit from DNA-PK inhibitors.

Gesa Junge, a PhD student at Newcastle University in the UK, and her colleagues conducted this research and presented the results at the AACR Annual Meeting 2015 (abstract 3624*). The work was supported by AstraZeneca.

The researchers’ goal was to validate that DNA-PK inhibition is a valid approach to chemosensitization in CLL. So the team tested NU7441—a compound that inhibits DNA-PK and PI3 kinase—and NDD0004—a more selective DNA-PK inhibitor.

The team isolated CLL cells from patients’ peripheral blood, cultured the cells, and treated them with mitoxantrone and/or 1μM of NDD0004 or 1μM of NU7441.

Junge and her colleagues found that NDD0004 sensitized cells to mitoxantrone more effectively than NU7441. Sensitization was 202-fold higher with NDD004 plus mitoxantrone than with mitoxantrone alone and 69-fold higher with NU7441 plus mitoxantrone than with mitoxantrone alone (P=0.02).

However, sensitization varied between CLL samples, and the researchers have yet to determine why. Their experiments showed that variability was not a result of DNA-PK levels.

Still, the team found that CLL cells from patients with poor prognostic markers were sensitive to DNA-PK inhibition.

Sensitization with NU7441 plus mitoxantrone was 69-fold higher than mitoxantrone alone in CLL samples with del(13q), 25-fold higher in samples with del(11q), 12-fold higher in samples with TP53 mutation, and 16-fold higher in samples with ATM dysfunction.

Sensitization with NDD0004 plus mitoxantrone was 201-fold higher than mitoxantrone alone in CLL samples with del(13q), 314-fold higher in samples with del(11q), 27-fold higher in samples with TP53 mutation, and 18-fold higher in samples with ATM dysfunction.

To confirm that sensitization was a result of DNA-PK inhibition, Junge and her colleagues tested NDD0004 in an isogenic pair of DNA-PK-deficient and DNA-PK-proficient HCT116 cells. They found that HCT116 cells lacking DNA-PK were not sensitive to NDD0004, but cells with DNA-PK were sensitive.

The researchers also investigated the mechanism of NDD0004. Their results suggest the drug works by inhibiting the repair of DNA double-strand breaks.

“What we think is happening is that we are inducing DNA damage with mitoxantrone, and that gets repaired by 24 hours,” Junge said. “But if the DNA-PK inhibitor is there, the damage persists, and that seems to translate quite nicely into an apoptosis response.”

To further this research, Junge and her colleagues are hoping to identify biomarkers that can help them determine which CLL patients are likely to respond to DNA-PK inhibitors.

*Information in the abstract differs from that presented at the meeting.

PHILADELPHIA—The tumor microenvironment may play a key role in treatment with CUDC-427, according to researchers.

Their experiments showed that certain diffuse large B-cell lymphoma (DLBCL) cell lines were sensitive to CUDC-427, and others were not.

However, co-culturing with stromal cells or TNF family ligands made resistant cell lines sensitive to CUDC-427.

And mice bearing cells that resisted CUDC-427 in vitro responded very well to treatment, experiencing complete tumor regression.

Ze Tian, PhD, and her colleagues from Curis, Inc. (the company developing CUDC-427) presented these findings at the AACR Annual Meeting 2015 (abstract 5502).

CUDC-427 is an inhibitor of apoptosis (IAP) antagonist that is in early stage clinical testing in patients with solid tumors and lymphomas.

For the current research, Dr Tian and her colleagues first evaluated the effects of CUDC-427 against a range of hematologic malignancies in vitro. They tested the drug in activated B-cell-like (ABC) DLBCL, germinal center B-cell-like (GCB) DLBCL, other non-Hodgkin lymphomas, Hodgkin lymphoma, multiple myeloma, and various leukemia cell lines.

DLBCL cells (both ABC and GCB) proved the most sensitive to treatment, and CUDC-427 induced apoptosis in these cells. However, certain DLBCL cell lines, such as Karpas 422, were not sensitive to treatment.

The researchers found they could remedy that in two ways. The presence of stromal cells in culture sensitized resistant DLBCL cells to treatment, as did TNF family ligands (TNFα or TRAIL). In previous research, TNF family ligands were shown to synergize with IAP antagonists.

The investigators then analyzed CUDC-427’s mechanism of action. In the sensitive WSU-DLCL2 cell line, the drug worked by activating caspases 3, 8, and 9 by inhibiting cIAP1 and XIAP, as well as activating the non-canonical NF-ĸB pathway and inducing TNFα.

In the resistant Karpas 422 cell line, there was no caspase activity following CUDC-427 treatment. However, when the researchers co-cultured the cell line with stromal cells, they saw caspase activity.

“Because of this finding, we think that the microenvironment may play a role in CUDC-427 treatment,” Dr Tian said.

So the investigators went on to test CUDC-427 in mouse models. The drug inhibited tumor growth by 94% in the WSU-DLCL2 xenograft model. But CUDC-427 induced complete tumor regression in the Karpas 422 xenograft model.

To further investigate the interaction between the tumor microenvironment and CUDC-427, the researchers tested the drug in the A20 B-cell lymphoma mouse syngeneic model.

They found that CUDC-427 induced tumor stasis in this fast-growing lymphoma. They believe this may be due, in part, to the high levels of TRAIL in this model.

Dr Tian and her colleagues said the interaction between CUDC-427 and TNF family ligands or stromal cells warrants further analysis. And this research supports additional investigation to improve outcomes in patients with DLBCL.

PHILADELPHIA—The tumor microenvironment may play a key role in treatment with CUDC-427, according to researchers.

Their experiments showed that certain diffuse large B-cell lymphoma (DLBCL) cell lines were sensitive to CUDC-427, and others were not.

However, co-culturing with stromal cells or TNF family ligands made resistant cell lines sensitive to CUDC-427.

And mice bearing cells that resisted CUDC-427 in vitro responded very well to treatment, experiencing complete tumor regression.

Ze Tian, PhD, and her colleagues from Curis, Inc. (the company developing CUDC-427) presented these findings at the AACR Annual Meeting 2015 (abstract 5502).

CUDC-427 is an inhibitor of apoptosis (IAP) antagonist that is in early stage clinical testing in patients with solid tumors and lymphomas.

For the current research, Dr Tian and her colleagues first evaluated the effects of CUDC-427 against a range of hematologic malignancies in vitro. They tested the drug in activated B-cell-like (ABC) DLBCL, germinal center B-cell-like (GCB) DLBCL, other non-Hodgkin lymphomas, Hodgkin lymphoma, multiple myeloma, and various leukemia cell lines.

DLBCL cells (both ABC and GCB) proved the most sensitive to treatment, and CUDC-427 induced apoptosis in these cells. However, certain DLBCL cell lines, such as Karpas 422, were not sensitive to treatment.

The researchers found they could remedy that in two ways. The presence of stromal cells in culture sensitized resistant DLBCL cells to treatment, as did TNF family ligands (TNFα or TRAIL). In previous research, TNF family ligands were shown to synergize with IAP antagonists.

The investigators then analyzed CUDC-427’s mechanism of action. In the sensitive WSU-DLCL2 cell line, the drug worked by activating caspases 3, 8, and 9 by inhibiting cIAP1 and XIAP, as well as activating the non-canonical NF-ĸB pathway and inducing TNFα.

In the resistant Karpas 422 cell line, there was no caspase activity following CUDC-427 treatment. However, when the researchers co-cultured the cell line with stromal cells, they saw caspase activity.

“Because of this finding, we think that the microenvironment may play a role in CUDC-427 treatment,” Dr Tian said.

So the investigators went on to test CUDC-427 in mouse models. The drug inhibited tumor growth by 94% in the WSU-DLCL2 xenograft model. But CUDC-427 induced complete tumor regression in the Karpas 422 xenograft model.

To further investigate the interaction between the tumor microenvironment and CUDC-427, the researchers tested the drug in the A20 B-cell lymphoma mouse syngeneic model.

They found that CUDC-427 induced tumor stasis in this fast-growing lymphoma. They believe this may be due, in part, to the high levels of TRAIL in this model.

Dr Tian and her colleagues said the interaction between CUDC-427 and TNF family ligands or stromal cells warrants further analysis. And this research supports additional investigation to improve outcomes in patients with DLBCL.

PHILADELPHIA—The tumor microenvironment may play a key role in treatment with CUDC-427, according to researchers.

Their experiments showed that certain diffuse large B-cell lymphoma (DLBCL) cell lines were sensitive to CUDC-427, and others were not.

However, co-culturing with stromal cells or TNF family ligands made resistant cell lines sensitive to CUDC-427.

And mice bearing cells that resisted CUDC-427 in vitro responded very well to treatment, experiencing complete tumor regression.

Ze Tian, PhD, and her colleagues from Curis, Inc. (the company developing CUDC-427) presented these findings at the AACR Annual Meeting 2015 (abstract 5502).

CUDC-427 is an inhibitor of apoptosis (IAP) antagonist that is in early stage clinical testing in patients with solid tumors and lymphomas.

For the current research, Dr Tian and her colleagues first evaluated the effects of CUDC-427 against a range of hematologic malignancies in vitro. They tested the drug in activated B-cell-like (ABC) DLBCL, germinal center B-cell-like (GCB) DLBCL, other non-Hodgkin lymphomas, Hodgkin lymphoma, multiple myeloma, and various leukemia cell lines.

DLBCL cells (both ABC and GCB) proved the most sensitive to treatment, and CUDC-427 induced apoptosis in these cells. However, certain DLBCL cell lines, such as Karpas 422, were not sensitive to treatment.

The researchers found they could remedy that in two ways. The presence of stromal cells in culture sensitized resistant DLBCL cells to treatment, as did TNF family ligands (TNFα or TRAIL). In previous research, TNF family ligands were shown to synergize with IAP antagonists.

The investigators then analyzed CUDC-427’s mechanism of action. In the sensitive WSU-DLCL2 cell line, the drug worked by activating caspases 3, 8, and 9 by inhibiting cIAP1 and XIAP, as well as activating the non-canonical NF-ĸB pathway and inducing TNFα.

In the resistant Karpas 422 cell line, there was no caspase activity following CUDC-427 treatment. However, when the researchers co-cultured the cell line with stromal cells, they saw caspase activity.

“Because of this finding, we think that the microenvironment may play a role in CUDC-427 treatment,” Dr Tian said.

So the investigators went on to test CUDC-427 in mouse models. The drug inhibited tumor growth by 94% in the WSU-DLCL2 xenograft model. But CUDC-427 induced complete tumor regression in the Karpas 422 xenograft model.

To further investigate the interaction between the tumor microenvironment and CUDC-427, the researchers tested the drug in the A20 B-cell lymphoma mouse syngeneic model.

They found that CUDC-427 induced tumor stasis in this fast-growing lymphoma. They believe this may be due, in part, to the high levels of TRAIL in this model.

Dr Tian and her colleagues said the interaction between CUDC-427 and TNF family ligands or stromal cells warrants further analysis. And this research supports additional investigation to improve outcomes in patients with DLBCL.

PHILADELPHIA—Results of preclinical research suggest the BCL-2 inhibitor ABT-199 (venetoclax) may be effective in certain pediatric patients with acute lymphoblastic leukemia (ALL).

In xenograft models of various ALL subtypes, ABT-199 produced an objective response rate below 30%.

However, additional analyses unearthed information that could potentially help us identify which ALL patients might respond to the drug.

Santi Suryani, PhD, of the Children’s Cancer Institute in Sydney, New South Wales, Australia, and her colleagues presented this research at the AACR Annual Meeting 2015 (abstract 3276*). The work was supported by AbbVie, one of the companies developing ABT-199.

Dr Suryani and her colleagues decided to investigate ABT-199 in pediatric ALL after observing mixed results with the BCL-2/BCL-W/BCL-XL inhibitor ABT-263 (navitoclax).

ABT-263 delayed ALL progression in nearly all of the xenograft models the team tested and produced a 61% response rate. However, the drug also induced BCL-XL-mediated thrombocytopenia.

As ABT-199 doesn’t target BCL-XL, the researchers thought the drug might produce similar responses as ABT-263 without inducing thrombocytopenia.

“When ABT-199 came into the picture, we were very excited,” Dr Suryani said. “We thought, ‘This is a wonder drug. This will cure pediatric ALL.’”

To test this hypothesis, the team compared ABT-199 (100 mg/kg x 21 days) and vehicle control in 19 pediatric ALL patient-derived xenografts, including infant mixed-lineage leukemia (MLL) ALL (n=4), B-cell precursor (BCP) ALL (n=5), BCP-ALL categorized as Ph-like (n=4), T-cell ALL (n=4), and early T-cell precursor (ETP) ALL (n=2).

ABT-199 significantly delayed progression in 12 xenografts (63%) for periods ranging from 0.4 days to 28 days. And the drug produced objective responses in 5 xenografts (26%).

Responses occurred in MLL-ALL, BCP-ALL, and Ph-like BCP ALL, but not T-cell ALL or ETP-ALL. Complete responses were seen in MLL-ALL (n=1) and BCP-ALL (n=2), and partial responses occurred in MLL-ALL (n=1) and Ph-like BCP-ALL (n=1).

As the response rate with ABT-263 was more than double that of ABT-199 (61% vs 26%), the researchers found the results with ABT-199 “a little bit disappointing,” according to Dr Suryani.

“But we thought, ‘That’s okay. That already tells us the science behind it—that pediatric ALL is probably more BCL-XL-dependent, rather than BCL-2-dependent,’” she said. “We wondered if there was any way we could come up with a predictive biomarker so we could select patients who will benefit from this treatment.”

With that in mind, the researchers evaluated the link between protein expression and response. They looked at BCL-2 and BCL-XL, as well as a range of other proteins, including BCL-W, MCL1, BAK1, and BAX, among others.

And they found that high BCL-XL and low BCL-2 expression were significantly associated with ABT-199 resistance.

The researchers are still investigating ways to guide treatment with ABT-199 in ALL. They are also hoping to improve responses by administering the drug in combination with other agents.

*Information in the abstract differs from that presented at the meeting.

PHILADELPHIA—Results of preclinical research suggest the BCL-2 inhibitor ABT-199 (venetoclax) may be effective in certain pediatric patients with acute lymphoblastic leukemia (ALL).

In xenograft models of various ALL subtypes, ABT-199 produced an objective response rate below 30%.

However, additional analyses unearthed information that could potentially help us identify which ALL patients might respond to the drug.

Santi Suryani, PhD, of the Children’s Cancer Institute in Sydney, New South Wales, Australia, and her colleagues presented this research at the AACR Annual Meeting 2015 (abstract 3276*). The work was supported by AbbVie, one of the companies developing ABT-199.

Dr Suryani and her colleagues decided to investigate ABT-199 in pediatric ALL after observing mixed results with the BCL-2/BCL-W/BCL-XL inhibitor ABT-263 (navitoclax).

ABT-263 delayed ALL progression in nearly all of the xenograft models the team tested and produced a 61% response rate. However, the drug also induced BCL-XL-mediated thrombocytopenia.

As ABT-199 doesn’t target BCL-XL, the researchers thought the drug might produce similar responses as ABT-263 without inducing thrombocytopenia.

“When ABT-199 came into the picture, we were very excited,” Dr Suryani said. “We thought, ‘This is a wonder drug. This will cure pediatric ALL.’”

To test this hypothesis, the team compared ABT-199 (100 mg/kg x 21 days) and vehicle control in 19 pediatric ALL patient-derived xenografts, including infant mixed-lineage leukemia (MLL) ALL (n=4), B-cell precursor (BCP) ALL (n=5), BCP-ALL categorized as Ph-like (n=4), T-cell ALL (n=4), and early T-cell precursor (ETP) ALL (n=2).

ABT-199 significantly delayed progression in 12 xenografts (63%) for periods ranging from 0.4 days to 28 days. And the drug produced objective responses in 5 xenografts (26%).

Responses occurred in MLL-ALL, BCP-ALL, and Ph-like BCP ALL, but not T-cell ALL or ETP-ALL. Complete responses were seen in MLL-ALL (n=1) and BCP-ALL (n=2), and partial responses occurred in MLL-ALL (n=1) and Ph-like BCP-ALL (n=1).

As the response rate with ABT-263 was more than double that of ABT-199 (61% vs 26%), the researchers found the results with ABT-199 “a little bit disappointing,” according to Dr Suryani.

“But we thought, ‘That’s okay. That already tells us the science behind it—that pediatric ALL is probably more BCL-XL-dependent, rather than BCL-2-dependent,’” she said. “We wondered if there was any way we could come up with a predictive biomarker so we could select patients who will benefit from this treatment.”

With that in mind, the researchers evaluated the link between protein expression and response. They looked at BCL-2 and BCL-XL, as well as a range of other proteins, including BCL-W, MCL1, BAK1, and BAX, among others.

And they found that high BCL-XL and low BCL-2 expression were significantly associated with ABT-199 resistance.

The researchers are still investigating ways to guide treatment with ABT-199 in ALL. They are also hoping to improve responses by administering the drug in combination with other agents.

*Information in the abstract differs from that presented at the meeting.

PHILADELPHIA—Results of preclinical research suggest the BCL-2 inhibitor ABT-199 (venetoclax) may be effective in certain pediatric patients with acute lymphoblastic leukemia (ALL).

In xenograft models of various ALL subtypes, ABT-199 produced an objective response rate below 30%.

However, additional analyses unearthed information that could potentially help us identify which ALL patients might respond to the drug.

Santi Suryani, PhD, of the Children’s Cancer Institute in Sydney, New South Wales, Australia, and her colleagues presented this research at the AACR Annual Meeting 2015 (abstract 3276*). The work was supported by AbbVie, one of the companies developing ABT-199.

Dr Suryani and her colleagues decided to investigate ABT-199 in pediatric ALL after observing mixed results with the BCL-2/BCL-W/BCL-XL inhibitor ABT-263 (navitoclax).

ABT-263 delayed ALL progression in nearly all of the xenograft models the team tested and produced a 61% response rate. However, the drug also induced BCL-XL-mediated thrombocytopenia.

As ABT-199 doesn’t target BCL-XL, the researchers thought the drug might produce similar responses as ABT-263 without inducing thrombocytopenia.

“When ABT-199 came into the picture, we were very excited,” Dr Suryani said. “We thought, ‘This is a wonder drug. This will cure pediatric ALL.’”

To test this hypothesis, the team compared ABT-199 (100 mg/kg x 21 days) and vehicle control in 19 pediatric ALL patient-derived xenografts, including infant mixed-lineage leukemia (MLL) ALL (n=4), B-cell precursor (BCP) ALL (n=5), BCP-ALL categorized as Ph-like (n=4), T-cell ALL (n=4), and early T-cell precursor (ETP) ALL (n=2).

ABT-199 significantly delayed progression in 12 xenografts (63%) for periods ranging from 0.4 days to 28 days. And the drug produced objective responses in 5 xenografts (26%).

Responses occurred in MLL-ALL, BCP-ALL, and Ph-like BCP ALL, but not T-cell ALL or ETP-ALL. Complete responses were seen in MLL-ALL (n=1) and BCP-ALL (n=2), and partial responses occurred in MLL-ALL (n=1) and Ph-like BCP-ALL (n=1).

As the response rate with ABT-263 was more than double that of ABT-199 (61% vs 26%), the researchers found the results with ABT-199 “a little bit disappointing,” according to Dr Suryani.

“But we thought, ‘That’s okay. That already tells us the science behind it—that pediatric ALL is probably more BCL-XL-dependent, rather than BCL-2-dependent,’” she said. “We wondered if there was any way we could come up with a predictive biomarker so we could select patients who will benefit from this treatment.”

With that in mind, the researchers evaluated the link between protein expression and response. They looked at BCL-2 and BCL-XL, as well as a range of other proteins, including BCL-W, MCL1, BAK1, and BAX, among others.

And they found that high BCL-XL and low BCL-2 expression were significantly associated with ABT-199 resistance.

The researchers are still investigating ways to guide treatment with ABT-199 in ALL. They are also hoping to improve responses by administering the drug in combination with other agents.

*Information in the abstract differs from that presented at the meeting.

AML cells in the bone marrow

PHILADELPHIA—Preclinical research suggests a novel agent has preferential activity in acute myeloid leukemia (AML) with FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutations.

The agent, VNLG-152, proved more cytotoxic in AML cell lines and patient samples with FLT3-ITD than in samples and cell lines with wild-type FLT3.

Exactly how and why this occurs remains somewhat of a mystery, however.

Sheetal Karne, MD, of the University of Maryland School of Medicine in Baltimore, and her colleagues detailed this mystery in a poster presentation at the AACR Annual Meeting 2015 (abstract 5408*).

Dr Karne noted that VNLG-152 targets translation by promoting the degradation of MAPK-interacting kinases (Mnks).

“[VNLG-152] has been previously published as functioning in Mnk degradation, which has been shown in triple-negative breast cancer and prostate cancer—in vivo and in vitro,” she said. “Our hypothesis was that, since [the drug] worked via decreasing translation, it would function in leukemia cells and, specifically, in leukemic cells with ITD mutations.”

So the investigators tested VNLG-152 in samples from AML patients, as well as both murine and human cell lines. They found that VNLG-152 was more cytotoxic in the presence of FLT3-ITD mutations, as evidenced by low micromolar IC₅₀ concentrations.

The IC₅₀ concentration was 3.4 μM in Ba/F3-ITD cells and 5.8 μM in Ba/F3-WT cells, which are murine cells transfected with human FLT3-ITD and wild-type FLT3, respectively. Similarly, the IC₅₀ concentration was 1.8 μM in 32D-ITD cells and 18.2 μM in 32D-WT cells.

In the human FLT3-ITD AML cell lines MV4-11 and MOLM-14, IC₅₀ concentrations were 2.3 μM and 4.2 μM, respectively. But concentrations were greater than 10 µM in the wild-type FLT3 human cell lines HL60 and U937.

In patient samples, the IC₅₀ concentration was 1.0 μM in FLT3-ITD AML and 7.5 μM in AML with wild-type FLT3.

In additional tests with murine cell lines, the investigators found that VNLG-152 inhibits the growth of Ba/F3-ITD and Ba/F3-WT cells. But the drug induces apoptosis in these cell lines only when given in high concentrations.

Looking into the mechanism of VNLG-152, the investigators found that the drug decreased Mnk-1 expression in Ba/F3-ITD and Ba/F3-WT cell lines.

“We saw that VNLG-152 worked via degradation of Mnk, but it was the same in both wild-type and ITD, so we’re still looking for an explanation as to what caused this difference,” Dr Karne said.

She and her colleagues believe the Mnk degradation inhibits the phosphorylation of eukaryotic translation initiation factor 4E (eIF4E), a downstream target of FLT3-ITD. But they are still investigating that possibility.

The team is also hoping to test VNLG-152 in combination with other drugs, such as FLT3 inhibitors or chemotherapeutic agents.

*Information in the abstract differs from that presented at the meeting.

AML cells in the bone marrow

PHILADELPHIA—Preclinical research suggests a novel agent has preferential activity in acute myeloid leukemia (AML) with FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutations.

The agent, VNLG-152, proved more cytotoxic in AML cell lines and patient samples with FLT3-ITD than in samples and cell lines with wild-type FLT3.

Exactly how and why this occurs remains somewhat of a mystery, however.

Sheetal Karne, MD, of the University of Maryland School of Medicine in Baltimore, and her colleagues detailed this mystery in a poster presentation at the AACR Annual Meeting 2015 (abstract 5408*).

Dr Karne noted that VNLG-152 targets translation by promoting the degradation of MAPK-interacting kinases (Mnks).

“[VNLG-152] has been previously published as functioning in Mnk degradation, which has been shown in triple-negative breast cancer and prostate cancer—in vivo and in vitro,” she said. “Our hypothesis was that, since [the drug] worked via decreasing translation, it would function in leukemia cells and, specifically, in leukemic cells with ITD mutations.”

So the investigators tested VNLG-152 in samples from AML patients, as well as both murine and human cell lines. They found that VNLG-152 was more cytotoxic in the presence of FLT3-ITD mutations, as evidenced by low micromolar IC₅₀ concentrations.

The IC₅₀ concentration was 3.4 μM in Ba/F3-ITD cells and 5.8 μM in Ba/F3-WT cells, which are murine cells transfected with human FLT3-ITD and wild-type FLT3, respectively. Similarly, the IC₅₀ concentration was 1.8 μM in 32D-ITD cells and 18.2 μM in 32D-WT cells.

In the human FLT3-ITD AML cell lines MV4-11 and MOLM-14, IC₅₀ concentrations were 2.3 μM and 4.2 μM, respectively. But concentrations were greater than 10 µM in the wild-type FLT3 human cell lines HL60 and U937.

In patient samples, the IC₅₀ concentration was 1.0 μM in FLT3-ITD AML and 7.5 μM in AML with wild-type FLT3.

In additional tests with murine cell lines, the investigators found that VNLG-152 inhibits the growth of Ba/F3-ITD and Ba/F3-WT cells. But the drug induces apoptosis in these cell lines only when given in high concentrations.

Looking into the mechanism of VNLG-152, the investigators found that the drug decreased Mnk-1 expression in Ba/F3-ITD and Ba/F3-WT cell lines.

“We saw that VNLG-152 worked via degradation of Mnk, but it was the same in both wild-type and ITD, so we’re still looking for an explanation as to what caused this difference,” Dr Karne said.

She and her colleagues believe the Mnk degradation inhibits the phosphorylation of eukaryotic translation initiation factor 4E (eIF4E), a downstream target of FLT3-ITD. But they are still investigating that possibility.

The team is also hoping to test VNLG-152 in combination with other drugs, such as FLT3 inhibitors or chemotherapeutic agents.

*Information in the abstract differs from that presented at the meeting.

AML cells in the bone marrow

PHILADELPHIA—Preclinical research suggests a novel agent has preferential activity in acute myeloid leukemia (AML) with FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutations.

The agent, VNLG-152, proved more cytotoxic in AML cell lines and patient samples with FLT3-ITD than in samples and cell lines with wild-type FLT3.

Exactly how and why this occurs remains somewhat of a mystery, however.

Sheetal Karne, MD, of the University of Maryland School of Medicine in Baltimore, and her colleagues detailed this mystery in a poster presentation at the AACR Annual Meeting 2015 (abstract 5408*).

Dr Karne noted that VNLG-152 targets translation by promoting the degradation of MAPK-interacting kinases (Mnks).

“[VNLG-152] has been previously published as functioning in Mnk degradation, which has been shown in triple-negative breast cancer and prostate cancer—in vivo and in vitro,” she said. “Our hypothesis was that, since [the drug] worked via decreasing translation, it would function in leukemia cells and, specifically, in leukemic cells with ITD mutations.”

So the investigators tested VNLG-152 in samples from AML patients, as well as both murine and human cell lines. They found that VNLG-152 was more cytotoxic in the presence of FLT3-ITD mutations, as evidenced by low micromolar IC₅₀ concentrations.

The IC₅₀ concentration was 3.4 μM in Ba/F3-ITD cells and 5.8 μM in Ba/F3-WT cells, which are murine cells transfected with human FLT3-ITD and wild-type FLT3, respectively. Similarly, the IC₅₀ concentration was 1.8 μM in 32D-ITD cells and 18.2 μM in 32D-WT cells.

In the human FLT3-ITD AML cell lines MV4-11 and MOLM-14, IC₅₀ concentrations were 2.3 μM and 4.2 μM, respectively. But concentrations were greater than 10 µM in the wild-type FLT3 human cell lines HL60 and U937.

In patient samples, the IC₅₀ concentration was 1.0 μM in FLT3-ITD AML and 7.5 μM in AML with wild-type FLT3.

In additional tests with murine cell lines, the investigators found that VNLG-152 inhibits the growth of Ba/F3-ITD and Ba/F3-WT cells. But the drug induces apoptosis in these cell lines only when given in high concentrations.

Looking into the mechanism of VNLG-152, the investigators found that the drug decreased Mnk-1 expression in Ba/F3-ITD and Ba/F3-WT cell lines.

“We saw that VNLG-152 worked via degradation of Mnk, but it was the same in both wild-type and ITD, so we’re still looking for an explanation as to what caused this difference,” Dr Karne said.

She and her colleagues believe the Mnk degradation inhibits the phosphorylation of eukaryotic translation initiation factor 4E (eIF4E), a downstream target of FLT3-ITD. But they are still investigating that possibility.

The team is also hoping to test VNLG-152 in combination with other drugs, such as FLT3 inhibitors or chemotherapeutic agents.

*Information in the abstract differs from that presented at the meeting.

A macrophage stretching its

pseudopodia to engulf particles

PHILADELPHIA—New research suggests the prognostic value of tumor-associated macrophages (TAMs) is disease-specific as well as treatment-specific.

Investigators set out to determine if TAMs have a negative prognostic impact in diffuse large B-cell lymphoma (DLBCL), as previous studies produced conflicting results.

The team found that higher TAM levels are associated with worse survival in DLBCL, but only in patients who do not receive rituximab. The drug can overcome the poor prognosis TAMs confer in DLBCL.

Eri Matsuki, MD, PhD, of Memorial Sloan-Kettering Cancer Center in New York, New York, and her colleagues presented these findings in a poster at the AACR Annual Meeting 2015 (abstract 2371*).

To ascertain the role of TAMs in DLBCL, the investigators analyzed specimens from 103 DLBCL patients, 61 of whom received rituximab, 33 who did not, and 9 whose rituximab status was unknown. The team first looked at the expression of CD163 as a marker of TAMs.

“CD163 is more specific to M2-type macrophages, which have pro-tumor effects, compared to a more pan-macrophage marker which is widely used—CD68,” Dr Matsuki noted.

She and her colleagues found that a high level of CD163-positive cells (more than 150) was significantly associated with advanced-stage disease (P=0.016), non-GCB DLBCL (P=0.0071), and higher expression of c-Myc (P=0.0022).

“Our interpretation of that at this point is that, the more aggressive the tumor, the more likely that it would induce macrophages into the tissue,” Dr Matsuki said.

The investigators then assessed the impact of rituximab use. Among patients who didn’t receive rituximab, having a high level of CD163-positive cells (more than 150) was associated with inferior overall survival (OS, P=0.022). However, if patients did receive rituximab, there was no significant difference in OS.

Dr Matsuki said this supports previous studies showing that the prognostic effect of TAMs diminishes with rituximab use, as well as the in vitro finding that M2 macrophages exhibit increased phagocytosis of rituximab-opsonized tumor cells.

“So overall, what we’re seeing is that . . . the negative influence of TAMs can be overcome with rituximab use,” she summarized.

Dr Matsuki and her colleagues also looked at the patients’ lymphocyte-to-monocyte-ratio (LMR) because TAMs partly arise from peripheral blood monocytes.

The team found that having an LMR higher than 2.77 was significantly associated with superior OS (P=0.03) in patients who did not receive rituximab. And there was a trend toward improved OS with a higher LMR in patients who did receive the drug (P=0.07).

The investigators believe the differences they observed in the prognostic value of CD163 and LMR could be explained by the fact that TAMs are derived from both circulating monocytes and resident macrophages.

Dr Matsuki said this research has improved her group’s understanding of DLBCL, but they are still working to identify additional biomarkers associated with prognosis in this disease.

*Information in the abstract differs from that presented at the meeting.

A macrophage stretching its

pseudopodia to engulf particles

PHILADELPHIA—New research suggests the prognostic value of tumor-associated macrophages (TAMs) is disease-specific as well as treatment-specific.

Investigators set out to determine if TAMs have a negative prognostic impact in diffuse large B-cell lymphoma (DLBCL), as previous studies produced conflicting results.

The team found that higher TAM levels are associated with worse survival in DLBCL, but only in patients who do not receive rituximab. The drug can overcome the poor prognosis TAMs confer in DLBCL.

Eri Matsuki, MD, PhD, of Memorial Sloan-Kettering Cancer Center in New York, New York, and her colleagues presented these findings in a poster at the AACR Annual Meeting 2015 (abstract 2371*).

To ascertain the role of TAMs in DLBCL, the investigators analyzed specimens from 103 DLBCL patients, 61 of whom received rituximab, 33 who did not, and 9 whose rituximab status was unknown. The team first looked at the expression of CD163 as a marker of TAMs.

“CD163 is more specific to M2-type macrophages, which have pro-tumor effects, compared to a more pan-macrophage marker which is widely used—CD68,” Dr Matsuki noted.

She and her colleagues found that a high level of CD163-positive cells (more than 150) was significantly associated with advanced-stage disease (P=0.016), non-GCB DLBCL (P=0.0071), and higher expression of c-Myc (P=0.0022).

“Our interpretation of that at this point is that, the more aggressive the tumor, the more likely that it would induce macrophages into the tissue,” Dr Matsuki said.

The investigators then assessed the impact of rituximab use. Among patients who didn’t receive rituximab, having a high level of CD163-positive cells (more than 150) was associated with inferior overall survival (OS, P=0.022). However, if patients did receive rituximab, there was no significant difference in OS.

Dr Matsuki said this supports previous studies showing that the prognostic effect of TAMs diminishes with rituximab use, as well as the in vitro finding that M2 macrophages exhibit increased phagocytosis of rituximab-opsonized tumor cells.

“So overall, what we’re seeing is that . . . the negative influence of TAMs can be overcome with rituximab use,” she summarized.

Dr Matsuki and her colleagues also looked at the patients’ lymphocyte-to-monocyte-ratio (LMR) because TAMs partly arise from peripheral blood monocytes.

The team found that having an LMR higher than 2.77 was significantly associated with superior OS (P=0.03) in patients who did not receive rituximab. And there was a trend toward improved OS with a higher LMR in patients who did receive the drug (P=0.07).

The investigators believe the differences they observed in the prognostic value of CD163 and LMR could be explained by the fact that TAMs are derived from both circulating monocytes and resident macrophages.

Dr Matsuki said this research has improved her group’s understanding of DLBCL, but they are still working to identify additional biomarkers associated with prognosis in this disease.

*Information in the abstract differs from that presented at the meeting.

A macrophage stretching its

pseudopodia to engulf particles

PHILADELPHIA—New research suggests the prognostic value of tumor-associated macrophages (TAMs) is disease-specific as well as treatment-specific.

Investigators set out to determine if TAMs have a negative prognostic impact in diffuse large B-cell lymphoma (DLBCL), as previous studies produced conflicting results.

The team found that higher TAM levels are associated with worse survival in DLBCL, but only in patients who do not receive rituximab. The drug can overcome the poor prognosis TAMs confer in DLBCL.

Eri Matsuki, MD, PhD, of Memorial Sloan-Kettering Cancer Center in New York, New York, and her colleagues presented these findings in a poster at the AACR Annual Meeting 2015 (abstract 2371*).

To ascertain the role of TAMs in DLBCL, the investigators analyzed specimens from 103 DLBCL patients, 61 of whom received rituximab, 33 who did not, and 9 whose rituximab status was unknown. The team first looked at the expression of CD163 as a marker of TAMs.

“CD163 is more specific to M2-type macrophages, which have pro-tumor effects, compared to a more pan-macrophage marker which is widely used—CD68,” Dr Matsuki noted.

She and her colleagues found that a high level of CD163-positive cells (more than 150) was significantly associated with advanced-stage disease (P=0.016), non-GCB DLBCL (P=0.0071), and higher expression of c-Myc (P=0.0022).

“Our interpretation of that at this point is that, the more aggressive the tumor, the more likely that it would induce macrophages into the tissue,” Dr Matsuki said.

The investigators then assessed the impact of rituximab use. Among patients who didn’t receive rituximab, having a high level of CD163-positive cells (more than 150) was associated with inferior overall survival (OS, P=0.022). However, if patients did receive rituximab, there was no significant difference in OS.

Dr Matsuki said this supports previous studies showing that the prognostic effect of TAMs diminishes with rituximab use, as well as the in vitro finding that M2 macrophages exhibit increased phagocytosis of rituximab-opsonized tumor cells.

“So overall, what we’re seeing is that . . . the negative influence of TAMs can be overcome with rituximab use,” she summarized.

Dr Matsuki and her colleagues also looked at the patients’ lymphocyte-to-monocyte-ratio (LMR) because TAMs partly arise from peripheral blood monocytes.

The team found that having an LMR higher than 2.77 was significantly associated with superior OS (P=0.03) in patients who did not receive rituximab. And there was a trend toward improved OS with a higher LMR in patients who did receive the drug (P=0.07).

The investigators believe the differences they observed in the prognostic value of CD163 and LMR could be explained by the fact that TAMs are derived from both circulating monocytes and resident macrophages.

Dr Matsuki said this research has improved her group’s understanding of DLBCL, but they are still working to identify additional biomarkers associated with prognosis in this disease.

*Information in the abstract differs from that presented at the meeting.

 

 

AACR Annual Meeting 2015

 

PHILADELPHIA—A retrospective study has revealed factors that appear to influence a person’s susceptibility to Waldenström’s macroglobulinemia (WM)/lymphoplasmacytic lymphoma (LPL) and other malignancies.

Study investigators looked at patients diagnosed with WM or LPL over a 20-year period and found about a 50% excess of second primary cancers in this population.

The patients had a significantly increased risk of multiple hematologic and solid tumor malignancies, and a few of these malignancies had shared susceptibility factors with WM/LPL.

The investigators believe that identifying these factors may prove useful for determining genetic susceptibility to WM/LPL.

Mary L. McMaster, MD, of the National Cancer Institute in Bethesda, Maryland, and her colleagues presented these findings at the AACR Annual Meeting 2015 (abstract 3709).

The team used data from the National Cancer Institute’s Surveillance, Epidemiology and End Results (SSER) database to evaluate the risk of subsequent primary cancer in 3825 patients diagnosed with WM (n=2163) or LPL (n=1662) from 1992 to 2011. The patients’ median age was 70, most of them were male (n=2221), and most were white (n=3153).

Dr McMaster said she and her colleagues looked at both WM and LPL in this study because SEER does not include information about immunoglobulin subtype, which makes it difficult to identify all WM cases with absolute certainty.

“[D]epending on what information a pathologist has when they review a bone marrow biopsy, for example, they may or may not know whether there’s IgM present,” Dr McMaster said. “So you may have a diagnosis of LPL and not have the information required to make the diagnosis of WM. For that reason, we combined both entities for this study.”

Dr McMaster and her colleagues calculated the observed-to-expected standardized incidence ratios (SIRs) for invasive cancers. After adjusting for multiple comparisons, the team found that survivors of WM/LPL had a significantly increased risk of developing a second primary malignancy (SIR=1.49).

This increased risk was seen for males and females and persisted throughout follow-up. The risk was higher for patients younger than 65 years of age (SIR=1.95).

Hematologic malignancies

WM/LPL survivors had a significantly increased risk of several hematologic malignancies. The SIR was 4.09 for all hematologic malignancies, 4.29 for lymphomas, and 3.16 for leukemias.

Dr McMaster pointed out that several lymphoma subtypes can have lymphoplasmacytic differentiation, the most common being marginal zone lymphoma. And this could potentially result in misclassification.

“So we actually ran the study with and without marginal zone lymphoma and saw no difference in the results,” she said. “So we don’t think misclassification accounts for the majority of what we’re seeing.”

The investigators found that WM/LPL survivors had the highest risk of developing Burkitt lymphoma (SIR=13.45), followed by Hodgkin lymphoma (SIR=9.80), T-cell non-Hodgkin lymphoma (SIR=6.62), mantle cell lymphoma (SIR=5.37), diffuse large B-cell lymphoma (DLBCL, SIR=4.76), multiple myeloma (SIR=4.40), any non-Hodgkin lymphoma (SIR=4.08), and acute myeloid leukemia (AML, SIR=3.27).

“Waldenström’s is known to transform, on occasion, to DLBCL,” Dr McMaster said. “So that may well account for the excess of DLBCL that we see in this population.”

She also noted that, prior to the early 2000s, WM was typically treated with alkylating agents. And alkylating agents have been linked to an increased risk of AML.

In this population, the risk of AML peaked 5 to 10 years after WM/LPL diagnosis and was only present in patients treated prior to 2002. This suggests the AML observed in this study was likely treatment-related.

Dr McMaster and her colleagues also found that WM/LPL survivors did not have a significantly increased risk of developing acute lymphocytic leukemia (SIR=0), hairy cell leukemia (SIR=0), chronic lymphocytic leukemia/small lymphocytic lymphoma (SIR=0.97), or follicular lymphoma (SIR=2.25).

Solid tumors

WM/LPL survivors did have a significantly increased risk of certain solid tumor malignancies. The overall SIR for solid tumors was 1.21.

The risk was significant for non-epithelial skin cancers (SIR=5.15), thyroid cancers (SIR=3.13), melanoma (SIR=1.72), and cancers of the lung and bronchus (SIR=1.44) or respiratory system (SIR=1.42).

“Melanoma has an immunological basis, as does Waldenström’s, so we think there may be some shared etiology there,” Dr McMaster said.

She also noted that a strong risk factor for thyroid cancer, particularly papillary thyroid cancer, is a history of autoimmune thyroid disease.

“Autoimmune disease of any sort is a risk factor for Waldenström’s macroglobulinemia,” she said. “So again, we think there might be a basis for shared susceptibility there.”

Dr McMaster said this research suggests that multiple primary cancers may occur in a single individual because of shared genetic susceptibility, shared environmental exposures, treatment effects, or chance. She believes future research will show that both genetic and environmental factors contribute to WM.

Investigators are currently conducting whole-exome sequencing studies and genome-wide association studies in patients with familial and spontaneous WM, with the hopes of identifying genes that contribute to WM susceptibility.

 

 

AACR Annual Meeting 2015

 

PHILADELPHIA—A retrospective study has revealed factors that appear to influence a person’s susceptibility to Waldenström’s macroglobulinemia (WM)/lymphoplasmacytic lymphoma (LPL) and other malignancies.

Study investigators looked at patients diagnosed with WM or LPL over a 20-year period and found about a 50% excess of second primary cancers in this population.

The patients had a significantly increased risk of multiple hematologic and solid tumor malignancies, and a few of these malignancies had shared susceptibility factors with WM/LPL.

The investigators believe that identifying these factors may prove useful for determining genetic susceptibility to WM/LPL.

Mary L. McMaster, MD, of the National Cancer Institute in Bethesda, Maryland, and her colleagues presented these findings at the AACR Annual Meeting 2015 (abstract 3709).

The team used data from the National Cancer Institute’s Surveillance, Epidemiology and End Results (SSER) database to evaluate the risk of subsequent primary cancer in 3825 patients diagnosed with WM (n=2163) or LPL (n=1662) from 1992 to 2011. The patients’ median age was 70, most of them were male (n=2221), and most were white (n=3153).

Dr McMaster said she and her colleagues looked at both WM and LPL in this study because SEER does not include information about immunoglobulin subtype, which makes it difficult to identify all WM cases with absolute certainty.

“[D]epending on what information a pathologist has when they review a bone marrow biopsy, for example, they may or may not know whether there’s IgM present,” Dr McMaster said. “So you may have a diagnosis of LPL and not have the information required to make the diagnosis of WM. For that reason, we combined both entities for this study.”

Dr McMaster and her colleagues calculated the observed-to-expected standardized incidence ratios (SIRs) for invasive cancers. After adjusting for multiple comparisons, the team found that survivors of WM/LPL had a significantly increased risk of developing a second primary malignancy (SIR=1.49).

This increased risk was seen for males and females and persisted throughout follow-up. The risk was higher for patients younger than 65 years of age (SIR=1.95).

Hematologic malignancies

WM/LPL survivors had a significantly increased risk of several hematologic malignancies. The SIR was 4.09 for all hematologic malignancies, 4.29 for lymphomas, and 3.16 for leukemias.

Dr McMaster pointed out that several lymphoma subtypes can have lymphoplasmacytic differentiation, the most common being marginal zone lymphoma. And this could potentially result in misclassification.

“So we actually ran the study with and without marginal zone lymphoma and saw no difference in the results,” she said. “So we don’t think misclassification accounts for the majority of what we’re seeing.”

The investigators found that WM/LPL survivors had the highest risk of developing Burkitt lymphoma (SIR=13.45), followed by Hodgkin lymphoma (SIR=9.80), T-cell non-Hodgkin lymphoma (SIR=6.62), mantle cell lymphoma (SIR=5.37), diffuse large B-cell lymphoma (DLBCL, SIR=4.76), multiple myeloma (SIR=4.40), any non-Hodgkin lymphoma (SIR=4.08), and acute myeloid leukemia (AML, SIR=3.27).

“Waldenström’s is known to transform, on occasion, to DLBCL,” Dr McMaster said. “So that may well account for the excess of DLBCL that we see in this population.”

She also noted that, prior to the early 2000s, WM was typically treated with alkylating agents. And alkylating agents have been linked to an increased risk of AML.

In this population, the risk of AML peaked 5 to 10 years after WM/LPL diagnosis and was only present in patients treated prior to 2002. This suggests the AML observed in this study was likely treatment-related.

Dr McMaster and her colleagues also found that WM/LPL survivors did not have a significantly increased risk of developing acute lymphocytic leukemia (SIR=0), hairy cell leukemia (SIR=0), chronic lymphocytic leukemia/small lymphocytic lymphoma (SIR=0.97), or follicular lymphoma (SIR=2.25).

Solid tumors

WM/LPL survivors did have a significantly increased risk of certain solid tumor malignancies. The overall SIR for solid tumors was 1.21.

The risk was significant for non-epithelial skin cancers (SIR=5.15), thyroid cancers (SIR=3.13), melanoma (SIR=1.72), and cancers of the lung and bronchus (SIR=1.44) or respiratory system (SIR=1.42).

“Melanoma has an immunological basis, as does Waldenström’s, so we think there may be some shared etiology there,” Dr McMaster said.

She also noted that a strong risk factor for thyroid cancer, particularly papillary thyroid cancer, is a history of autoimmune thyroid disease.

“Autoimmune disease of any sort is a risk factor for Waldenström’s macroglobulinemia,” she said. “So again, we think there might be a basis for shared susceptibility there.”

Dr McMaster said this research suggests that multiple primary cancers may occur in a single individual because of shared genetic susceptibility, shared environmental exposures, treatment effects, or chance. She believes future research will show that both genetic and environmental factors contribute to WM.

Investigators are currently conducting whole-exome sequencing studies and genome-wide association studies in patients with familial and spontaneous WM, with the hopes of identifying genes that contribute to WM susceptibility.

 

 

AACR Annual Meeting 2015

 

PHILADELPHIA—A retrospective study has revealed factors that appear to influence a person’s susceptibility to Waldenström’s macroglobulinemia (WM)/lymphoplasmacytic lymphoma (LPL) and other malignancies.

Study investigators looked at patients diagnosed with WM or LPL over a 20-year period and found about a 50% excess of second primary cancers in this population.

The patients had a significantly increased risk of multiple hematologic and solid tumor malignancies, and a few of these malignancies had shared susceptibility factors with WM/LPL.

The investigators believe that identifying these factors may prove useful for determining genetic susceptibility to WM/LPL.

Mary L. McMaster, MD, of the National Cancer Institute in Bethesda, Maryland, and her colleagues presented these findings at the AACR Annual Meeting 2015 (abstract 3709).

The team used data from the National Cancer Institute’s Surveillance, Epidemiology and End Results (SSER) database to evaluate the risk of subsequent primary cancer in 3825 patients diagnosed with WM (n=2163) or LPL (n=1662) from 1992 to 2011. The patients’ median age was 70, most of them were male (n=2221), and most were white (n=3153).

Dr McMaster said she and her colleagues looked at both WM and LPL in this study because SEER does not include information about immunoglobulin subtype, which makes it difficult to identify all WM cases with absolute certainty.

“[D]epending on what information a pathologist has when they review a bone marrow biopsy, for example, they may or may not know whether there’s IgM present,” Dr McMaster said. “So you may have a diagnosis of LPL and not have the information required to make the diagnosis of WM. For that reason, we combined both entities for this study.”

Dr McMaster and her colleagues calculated the observed-to-expected standardized incidence ratios (SIRs) for invasive cancers. After adjusting for multiple comparisons, the team found that survivors of WM/LPL had a significantly increased risk of developing a second primary malignancy (SIR=1.49).

This increased risk was seen for males and females and persisted throughout follow-up. The risk was higher for patients younger than 65 years of age (SIR=1.95).

Hematologic malignancies

WM/LPL survivors had a significantly increased risk of several hematologic malignancies. The SIR was 4.09 for all hematologic malignancies, 4.29 for lymphomas, and 3.16 for leukemias.

Dr McMaster pointed out that several lymphoma subtypes can have lymphoplasmacytic differentiation, the most common being marginal zone lymphoma. And this could potentially result in misclassification.

“So we actually ran the study with and without marginal zone lymphoma and saw no difference in the results,” she said. “So we don’t think misclassification accounts for the majority of what we’re seeing.”

The investigators found that WM/LPL survivors had the highest risk of developing Burkitt lymphoma (SIR=13.45), followed by Hodgkin lymphoma (SIR=9.80), T-cell non-Hodgkin lymphoma (SIR=6.62), mantle cell lymphoma (SIR=5.37), diffuse large B-cell lymphoma (DLBCL, SIR=4.76), multiple myeloma (SIR=4.40), any non-Hodgkin lymphoma (SIR=4.08), and acute myeloid leukemia (AML, SIR=3.27).

“Waldenström’s is known to transform, on occasion, to DLBCL,” Dr McMaster said. “So that may well account for the excess of DLBCL that we see in this population.”

She also noted that, prior to the early 2000s, WM was typically treated with alkylating agents. And alkylating agents have been linked to an increased risk of AML.

In this population, the risk of AML peaked 5 to 10 years after WM/LPL diagnosis and was only present in patients treated prior to 2002. This suggests the AML observed in this study was likely treatment-related.

Dr McMaster and her colleagues also found that WM/LPL survivors did not have a significantly increased risk of developing acute lymphocytic leukemia (SIR=0), hairy cell leukemia (SIR=0), chronic lymphocytic leukemia/small lymphocytic lymphoma (SIR=0.97), or follicular lymphoma (SIR=2.25).

Solid tumors

WM/LPL survivors did have a significantly increased risk of certain solid tumor malignancies. The overall SIR for solid tumors was 1.21.

The risk was significant for non-epithelial skin cancers (SIR=5.15), thyroid cancers (SIR=3.13), melanoma (SIR=1.72), and cancers of the lung and bronchus (SIR=1.44) or respiratory system (SIR=1.42).

“Melanoma has an immunological basis, as does Waldenström’s, so we think there may be some shared etiology there,” Dr McMaster said.

She also noted that a strong risk factor for thyroid cancer, particularly papillary thyroid cancer, is a history of autoimmune thyroid disease.

“Autoimmune disease of any sort is a risk factor for Waldenström’s macroglobulinemia,” she said. “So again, we think there might be a basis for shared susceptibility there.”

Dr McMaster said this research suggests that multiple primary cancers may occur in a single individual because of shared genetic susceptibility, shared environmental exposures, treatment effects, or chance. She believes future research will show that both genetic and environmental factors contribute to WM.

Investigators are currently conducting whole-exome sequencing studies and genome-wide association studies in patients with familial and spontaneous WM, with the hopes of identifying genes that contribute to WM susceptibility.