TBD Meeting (5324-22)

A 27-gene immuno-oncology assay appears to provide useful information about whether patients with advanced non–small cell lung cancer (NSCLC) could benefit from immune checkpoint inhibitor (ICI) therapy despite their poor status, researchers reported.

Positive findings on the test, known as DetermaIO, were “associated with efficacy of response to ICI therapy in advanced NSCLC patients,” Matthew G. Varga, PhD, manager of scientific affairs at Oncocyte, said in an interview. “These data suggest that DetermaIO warrants further study in poor performance status patients as it has the potential to identify likely responders to ICI therapy.”

Oncocyte, which is developing the test, presented the findings in a poster at the annual meeting of the Society for Immunotherapy of Cancer.

According to Dr. Varga, “DetermaIO is an RT-qPCR test that can be applied to FFPE [formalin-fixed, paraffin-embedded] tissue specimens to quantify the relative gene expression of 27 genes and subsequently applies our proprietary algorithm to generate an IO score based on the gene expression profile. The DetermaIO score is a binary IO+ or IO– score, representing likely responder or nonresponder, respectively.”

The test was originally developed for triple negative breast cancer, Dr. Varga said, and it’s been validated in non–small cell lung cancer, metastatic urothelial carcinoma, and metastatic colorectal carcinoma.

For the study, the researchers retrospectively tracked associations between DetermaIO score and either progression-free survival (PFS) or overall survival (OS) in 147 patients in Canada with NSCLC who were treated with ICI monotherapy. All had programmed death-ligand 1 (PD-L1) ≥ 50%.

Overall, outcomes were poor: The median survival was 12.7 months, and median PFS was 7.0 months. These outcomes were even worse in those who underwent therapy as a second- line treatment: The median survival was 9.7 months, and median PFS was 4.4 months.

“DetermaIO was significantly associated with PFS at hazard ratio [HR] = 0.55, 95% [confidence interval] CI, 0.32-0.94, P = .028. In our analyses, a hazard ratio less than 1 suggests lower risk – i.e, that DetermaIO+ patients have lower risk of an event – death or progression – compared to a DetermaIO– patient,” Dr. Varga said. “The association for overall survival was not statistically significant, but it was suggestive of clinically meaningful benefit.”

He added that “we could identify likely responders from nonresponders, suggesting that the DetermaIO score adds both independent and incremental data to the existing gold standard biomarker. The objective response rate for all first-line patients – n = 78 – was 44.9%. Twenty-two DetermaIO– tumors had a 23% response rate (5 partial responses) whereas of the 56 DetermaIO+ patients, the response rate was 54% (2 complete response and 28 partial responses).”

A score on the test, he said, was not associated with OS or PFS in patients who received second-line or later treatment.

The study was not designed to evaluate the predictive power of the test. “For a biomarker to be defined as predictive requires a formal test of interaction between a treatment group (ICI monotherapy, for example) vs. a control group (chemo-only or other regimen),” Dr. Varga explained. “In our analysis, there was no group of patients who did not receive ICI monotherapy. Thus a test for interaction and a predictive claim cannot be made.”

The test is available for at no cost via an early access program, Dr. Varga said, and Oncocyte is getting ready to seek Medicare coverage. The ultimate cost of the test, he said, is unknown.

Oncocyte funded this study. Dr. Varga and several other study authors are Oncocyte employees, and another author is a paid consultant to the company.

A 27-gene immuno-oncology assay appears to provide useful information about whether patients with advanced non–small cell lung cancer (NSCLC) could benefit from immune checkpoint inhibitor (ICI) therapy despite their poor status, researchers reported.

Positive findings on the test, known as DetermaIO, were “associated with efficacy of response to ICI therapy in advanced NSCLC patients,” Matthew G. Varga, PhD, manager of scientific affairs at Oncocyte, said in an interview. “These data suggest that DetermaIO warrants further study in poor performance status patients as it has the potential to identify likely responders to ICI therapy.”

Oncocyte, which is developing the test, presented the findings in a poster at the annual meeting of the Society for Immunotherapy of Cancer.

According to Dr. Varga, “DetermaIO is an RT-qPCR test that can be applied to FFPE [formalin-fixed, paraffin-embedded] tissue specimens to quantify the relative gene expression of 27 genes and subsequently applies our proprietary algorithm to generate an IO score based on the gene expression profile. The DetermaIO score is a binary IO+ or IO– score, representing likely responder or nonresponder, respectively.”

The test was originally developed for triple negative breast cancer, Dr. Varga said, and it’s been validated in non–small cell lung cancer, metastatic urothelial carcinoma, and metastatic colorectal carcinoma.

For the study, the researchers retrospectively tracked associations between DetermaIO score and either progression-free survival (PFS) or overall survival (OS) in 147 patients in Canada with NSCLC who were treated with ICI monotherapy. All had programmed death-ligand 1 (PD-L1) ≥ 50%.

Overall, outcomes were poor: The median survival was 12.7 months, and median PFS was 7.0 months. These outcomes were even worse in those who underwent therapy as a second- line treatment: The median survival was 9.7 months, and median PFS was 4.4 months.

“DetermaIO was significantly associated with PFS at hazard ratio [HR] = 0.55, 95% [confidence interval] CI, 0.32-0.94, P = .028. In our analyses, a hazard ratio less than 1 suggests lower risk – i.e, that DetermaIO+ patients have lower risk of an event – death or progression – compared to a DetermaIO– patient,” Dr. Varga said. “The association for overall survival was not statistically significant, but it was suggestive of clinically meaningful benefit.”

He added that “we could identify likely responders from nonresponders, suggesting that the DetermaIO score adds both independent and incremental data to the existing gold standard biomarker. The objective response rate for all first-line patients – n = 78 – was 44.9%. Twenty-two DetermaIO– tumors had a 23% response rate (5 partial responses) whereas of the 56 DetermaIO+ patients, the response rate was 54% (2 complete response and 28 partial responses).”

A score on the test, he said, was not associated with OS or PFS in patients who received second-line or later treatment.

The study was not designed to evaluate the predictive power of the test. “For a biomarker to be defined as predictive requires a formal test of interaction between a treatment group (ICI monotherapy, for example) vs. a control group (chemo-only or other regimen),” Dr. Varga explained. “In our analysis, there was no group of patients who did not receive ICI monotherapy. Thus a test for interaction and a predictive claim cannot be made.”

The test is available for at no cost via an early access program, Dr. Varga said, and Oncocyte is getting ready to seek Medicare coverage. The ultimate cost of the test, he said, is unknown.

Oncocyte funded this study. Dr. Varga and several other study authors are Oncocyte employees, and another author is a paid consultant to the company.

A 27-gene immuno-oncology assay appears to provide useful information about whether patients with advanced non–small cell lung cancer (NSCLC) could benefit from immune checkpoint inhibitor (ICI) therapy despite their poor status, researchers reported.

Positive findings on the test, known as DetermaIO, were “associated with efficacy of response to ICI therapy in advanced NSCLC patients,” Matthew G. Varga, PhD, manager of scientific affairs at Oncocyte, said in an interview. “These data suggest that DetermaIO warrants further study in poor performance status patients as it has the potential to identify likely responders to ICI therapy.”

Oncocyte, which is developing the test, presented the findings in a poster at the annual meeting of the Society for Immunotherapy of Cancer.

According to Dr. Varga, “DetermaIO is an RT-qPCR test that can be applied to FFPE [formalin-fixed, paraffin-embedded] tissue specimens to quantify the relative gene expression of 27 genes and subsequently applies our proprietary algorithm to generate an IO score based on the gene expression profile. The DetermaIO score is a binary IO+ or IO– score, representing likely responder or nonresponder, respectively.”

The test was originally developed for triple negative breast cancer, Dr. Varga said, and it’s been validated in non–small cell lung cancer, metastatic urothelial carcinoma, and metastatic colorectal carcinoma.

For the study, the researchers retrospectively tracked associations between DetermaIO score and either progression-free survival (PFS) or overall survival (OS) in 147 patients in Canada with NSCLC who were treated with ICI monotherapy. All had programmed death-ligand 1 (PD-L1) ≥ 50%.

Overall, outcomes were poor: The median survival was 12.7 months, and median PFS was 7.0 months. These outcomes were even worse in those who underwent therapy as a second- line treatment: The median survival was 9.7 months, and median PFS was 4.4 months.

“DetermaIO was significantly associated with PFS at hazard ratio [HR] = 0.55, 95% [confidence interval] CI, 0.32-0.94, P = .028. In our analyses, a hazard ratio less than 1 suggests lower risk – i.e, that DetermaIO+ patients have lower risk of an event – death or progression – compared to a DetermaIO– patient,” Dr. Varga said. “The association for overall survival was not statistically significant, but it was suggestive of clinically meaningful benefit.”

He added that “we could identify likely responders from nonresponders, suggesting that the DetermaIO score adds both independent and incremental data to the existing gold standard biomarker. The objective response rate for all first-line patients – n = 78 – was 44.9%. Twenty-two DetermaIO– tumors had a 23% response rate (5 partial responses) whereas of the 56 DetermaIO+ patients, the response rate was 54% (2 complete response and 28 partial responses).”

A score on the test, he said, was not associated with OS or PFS in patients who received second-line or later treatment.

The study was not designed to evaluate the predictive power of the test. “For a biomarker to be defined as predictive requires a formal test of interaction between a treatment group (ICI monotherapy, for example) vs. a control group (chemo-only or other regimen),” Dr. Varga explained. “In our analysis, there was no group of patients who did not receive ICI monotherapy. Thus a test for interaction and a predictive claim cannot be made.”

The test is available for at no cost via an early access program, Dr. Varga said, and Oncocyte is getting ready to seek Medicare coverage. The ultimate cost of the test, he said, is unknown.

Oncocyte funded this study. Dr. Varga and several other study authors are Oncocyte employees, and another author is a paid consultant to the company.

In human papillomavirus (HPV)-positive, locally advanced oropharyngeal squamous cell carcinoma, an immune checkpoint blockade regimen combined with radiotherapy led to good survival with a reduction in radiation exposure.

First-line therapy for HPV-positive oropharynx cancer is generally high-dose cisplatin combined with high-dose radiotherapy, but this regimen is associated with significant acute and long-term toxicity.

In previous studies among patients with recurrent or metastatic squamous cell carcinoma, nivolumab (Opdiva, Bristol Myers Squibb) improved survival when combined with platinum-based chemotherapy, and pembrolizumab (Keytruda, Merck) improved survival in recurrent disease compared with chemotherapy plus cetuximab.

Those precedents predicted success for HPV-positive oropharynx cancer, according to Maura Gillison, MD, PhD, who presented the results at a press briefing held in November in advance of the Society for Immunotherapy of Cancer’s 37th Annual Meeting. “Given that HPV-positive oropharynx cancers are characterized by an inflamed tumor microenvironment and HPV oncoproteins are omnipresent, required for cancer survival, and are ideal tumor-specific antigens – we hypothesized that induction and concurrent CTLA-4 and PD-1 immune checkpoint blockade, followed by volume- and dose-adapted IMRT (intensity-modulated radiotherapy), would be an effective alternative to the current standard of care,” said Dr. Gillison, who is a professor of medicine at the University of Texas MD Anderson Cancer Center, Houston.

Anti–PD-L1 therapy is approved for head and neck cancer, but the frontier is moving it into the locally advanced setting in combination with CTLA-4 inhibitors, according to Robert Ferris, MD, PhD, who moderated the press briefing and was lead author of the nivolumab in metastatic squamous cell carcinoma study. He added that recent trial data suggest this approach should be more effective and create more durable responses.

The new data support the approach. “The trial provides compelling data to support a new approach for treating newly diagnosed HPV-positive head and neck cancers. Our goal is to treat this cancer with immunotherapy alone. The results of this trial make me optimistic that this will be achievable,” Dr. Gillison said.
 

The study details

The researchers conducted a phase 2 clinical trial, enrolling 35 patients with newly diagnosed HPV-positive oropharynx cancer who were positive for PD-L1 expression.

Patients received 1 mg/kg ipilimumab (Yervoy, Bristol Myers Squibb) and 3 mg/kg nivolumab over a 6-week cycle, followed by a second cycle that was accompanied by 40-44 Gy radiotherapy for patients with a complete response in their primary tumor, and a boost to 50-66 based on postinduction treatment volume. The protocol reduced dose to the neck from 52 to 36 Gy. The radiation was delivered to only one nodal echelon beyond the involved node. Standard care delivers radiotherapy to essentially the entire neck, Dr. Gillison said.

Grade 3 or higher adverse events occurred in 66% of patients, the majority of which were attributable to radiotherapy. The complete response rate was 94% at 6 months as assessed by PET scan, and 2-year progression-free survival was 86%. After a median follow-up of 14.9 months, all patients were alive and cancer-free.

Overall response rate was 14% following induction, but 96% showed a histologic treatment effect. Tumor viability was less than 5% in 48% of patients, and a molecular complete response was observed in 30% as measured by plasma cell-free HPV. Patients received 36% less radiation than typical of standard of care, and the dose to critical areas was reduced by 50%.

At the press conference, Dr. Ferris asked Dr. Gillison whether the researchers observed a spike in cell-free HPV DNA before the decline occurred, suggesting evidence of tumor death and DNA release.

“We did see in a remarkable number of patients within 2 weeks of the first dose, a very strong peak in the cell-free HPV DNA, followed by a rapid decline. In those patients who still have viable tumor at the end of induction immunotherapy, we saw a second robust peak in cell-free HPV DNA at the start of radiation, with rapid clearance. So that gave us confidence that (among) those patients who had cell-free HPV clearance by the end of induction, followed by no further detection through radiation, that it’s an excellent surrogate for tumor control,” Dr. Gillison said.

Dr. Gillison has financial relationships with Eisai, Exilixis, Caladrius, iTeos, Istari, Seagen, Sensei, Bicara, Mirati, Coherus, Debiopharm, Kura, Shattuck, Nektar, Ipsen, EMD Serono, Gilead, LXS, BioNTech, Merck, Bristol Myers Squibb, Bayer, Roche, Genocea, NewLink Genetics, Aspyrian, TRM Oncology, Amgen, AstraZeneca, Celgene, and Agenus. Dr. Ferris has financial relationships with Bristol Myers Squibb, AstraZeneca/MedImmune, Merck, and Celgene.

In human papillomavirus (HPV)-positive, locally advanced oropharyngeal squamous cell carcinoma, an immune checkpoint blockade regimen combined with radiotherapy led to good survival with a reduction in radiation exposure.

First-line therapy for HPV-positive oropharynx cancer is generally high-dose cisplatin combined with high-dose radiotherapy, but this regimen is associated with significant acute and long-term toxicity.

In previous studies among patients with recurrent or metastatic squamous cell carcinoma, nivolumab (Opdiva, Bristol Myers Squibb) improved survival when combined with platinum-based chemotherapy, and pembrolizumab (Keytruda, Merck) improved survival in recurrent disease compared with chemotherapy plus cetuximab.

Those precedents predicted success for HPV-positive oropharynx cancer, according to Maura Gillison, MD, PhD, who presented the results at a press briefing held in November in advance of the Society for Immunotherapy of Cancer’s 37th Annual Meeting. “Given that HPV-positive oropharynx cancers are characterized by an inflamed tumor microenvironment and HPV oncoproteins are omnipresent, required for cancer survival, and are ideal tumor-specific antigens – we hypothesized that induction and concurrent CTLA-4 and PD-1 immune checkpoint blockade, followed by volume- and dose-adapted IMRT (intensity-modulated radiotherapy), would be an effective alternative to the current standard of care,” said Dr. Gillison, who is a professor of medicine at the University of Texas MD Anderson Cancer Center, Houston.

Anti–PD-L1 therapy is approved for head and neck cancer, but the frontier is moving it into the locally advanced setting in combination with CTLA-4 inhibitors, according to Robert Ferris, MD, PhD, who moderated the press briefing and was lead author of the nivolumab in metastatic squamous cell carcinoma study. He added that recent trial data suggest this approach should be more effective and create more durable responses.

The new data support the approach. “The trial provides compelling data to support a new approach for treating newly diagnosed HPV-positive head and neck cancers. Our goal is to treat this cancer with immunotherapy alone. The results of this trial make me optimistic that this will be achievable,” Dr. Gillison said.
 

The study details

The researchers conducted a phase 2 clinical trial, enrolling 35 patients with newly diagnosed HPV-positive oropharynx cancer who were positive for PD-L1 expression.

Patients received 1 mg/kg ipilimumab (Yervoy, Bristol Myers Squibb) and 3 mg/kg nivolumab over a 6-week cycle, followed by a second cycle that was accompanied by 40-44 Gy radiotherapy for patients with a complete response in their primary tumor, and a boost to 50-66 based on postinduction treatment volume. The protocol reduced dose to the neck from 52 to 36 Gy. The radiation was delivered to only one nodal echelon beyond the involved node. Standard care delivers radiotherapy to essentially the entire neck, Dr. Gillison said.

Grade 3 or higher adverse events occurred in 66% of patients, the majority of which were attributable to radiotherapy. The complete response rate was 94% at 6 months as assessed by PET scan, and 2-year progression-free survival was 86%. After a median follow-up of 14.9 months, all patients were alive and cancer-free.

Overall response rate was 14% following induction, but 96% showed a histologic treatment effect. Tumor viability was less than 5% in 48% of patients, and a molecular complete response was observed in 30% as measured by plasma cell-free HPV. Patients received 36% less radiation than typical of standard of care, and the dose to critical areas was reduced by 50%.

At the press conference, Dr. Ferris asked Dr. Gillison whether the researchers observed a spike in cell-free HPV DNA before the decline occurred, suggesting evidence of tumor death and DNA release.

“We did see in a remarkable number of patients within 2 weeks of the first dose, a very strong peak in the cell-free HPV DNA, followed by a rapid decline. In those patients who still have viable tumor at the end of induction immunotherapy, we saw a second robust peak in cell-free HPV DNA at the start of radiation, with rapid clearance. So that gave us confidence that (among) those patients who had cell-free HPV clearance by the end of induction, followed by no further detection through radiation, that it’s an excellent surrogate for tumor control,” Dr. Gillison said.

Dr. Gillison has financial relationships with Eisai, Exilixis, Caladrius, iTeos, Istari, Seagen, Sensei, Bicara, Mirati, Coherus, Debiopharm, Kura, Shattuck, Nektar, Ipsen, EMD Serono, Gilead, LXS, BioNTech, Merck, Bristol Myers Squibb, Bayer, Roche, Genocea, NewLink Genetics, Aspyrian, TRM Oncology, Amgen, AstraZeneca, Celgene, and Agenus. Dr. Ferris has financial relationships with Bristol Myers Squibb, AstraZeneca/MedImmune, Merck, and Celgene.

In human papillomavirus (HPV)-positive, locally advanced oropharyngeal squamous cell carcinoma, an immune checkpoint blockade regimen combined with radiotherapy led to good survival with a reduction in radiation exposure.

First-line therapy for HPV-positive oropharynx cancer is generally high-dose cisplatin combined with high-dose radiotherapy, but this regimen is associated with significant acute and long-term toxicity.

In previous studies among patients with recurrent or metastatic squamous cell carcinoma, nivolumab (Opdiva, Bristol Myers Squibb) improved survival when combined with platinum-based chemotherapy, and pembrolizumab (Keytruda, Merck) improved survival in recurrent disease compared with chemotherapy plus cetuximab.

Those precedents predicted success for HPV-positive oropharynx cancer, according to Maura Gillison, MD, PhD, who presented the results at a press briefing held in November in advance of the Society for Immunotherapy of Cancer’s 37th Annual Meeting. “Given that HPV-positive oropharynx cancers are characterized by an inflamed tumor microenvironment and HPV oncoproteins are omnipresent, required for cancer survival, and are ideal tumor-specific antigens – we hypothesized that induction and concurrent CTLA-4 and PD-1 immune checkpoint blockade, followed by volume- and dose-adapted IMRT (intensity-modulated radiotherapy), would be an effective alternative to the current standard of care,” said Dr. Gillison, who is a professor of medicine at the University of Texas MD Anderson Cancer Center, Houston.

Anti–PD-L1 therapy is approved for head and neck cancer, but the frontier is moving it into the locally advanced setting in combination with CTLA-4 inhibitors, according to Robert Ferris, MD, PhD, who moderated the press briefing and was lead author of the nivolumab in metastatic squamous cell carcinoma study. He added that recent trial data suggest this approach should be more effective and create more durable responses.

The new data support the approach. “The trial provides compelling data to support a new approach for treating newly diagnosed HPV-positive head and neck cancers. Our goal is to treat this cancer with immunotherapy alone. The results of this trial make me optimistic that this will be achievable,” Dr. Gillison said.
 

The study details

The researchers conducted a phase 2 clinical trial, enrolling 35 patients with newly diagnosed HPV-positive oropharynx cancer who were positive for PD-L1 expression.

Patients received 1 mg/kg ipilimumab (Yervoy, Bristol Myers Squibb) and 3 mg/kg nivolumab over a 6-week cycle, followed by a second cycle that was accompanied by 40-44 Gy radiotherapy for patients with a complete response in their primary tumor, and a boost to 50-66 based on postinduction treatment volume. The protocol reduced dose to the neck from 52 to 36 Gy. The radiation was delivered to only one nodal echelon beyond the involved node. Standard care delivers radiotherapy to essentially the entire neck, Dr. Gillison said.

Grade 3 or higher adverse events occurred in 66% of patients, the majority of which were attributable to radiotherapy. The complete response rate was 94% at 6 months as assessed by PET scan, and 2-year progression-free survival was 86%. After a median follow-up of 14.9 months, all patients were alive and cancer-free.

Overall response rate was 14% following induction, but 96% showed a histologic treatment effect. Tumor viability was less than 5% in 48% of patients, and a molecular complete response was observed in 30% as measured by plasma cell-free HPV. Patients received 36% less radiation than typical of standard of care, and the dose to critical areas was reduced by 50%.

At the press conference, Dr. Ferris asked Dr. Gillison whether the researchers observed a spike in cell-free HPV DNA before the decline occurred, suggesting evidence of tumor death and DNA release.

“We did see in a remarkable number of patients within 2 weeks of the first dose, a very strong peak in the cell-free HPV DNA, followed by a rapid decline. In those patients who still have viable tumor at the end of induction immunotherapy, we saw a second robust peak in cell-free HPV DNA at the start of radiation, with rapid clearance. So that gave us confidence that (among) those patients who had cell-free HPV clearance by the end of induction, followed by no further detection through radiation, that it’s an excellent surrogate for tumor control,” Dr. Gillison said.

Dr. Gillison has financial relationships with Eisai, Exilixis, Caladrius, iTeos, Istari, Seagen, Sensei, Bicara, Mirati, Coherus, Debiopharm, Kura, Shattuck, Nektar, Ipsen, EMD Serono, Gilead, LXS, BioNTech, Merck, Bristol Myers Squibb, Bayer, Roche, Genocea, NewLink Genetics, Aspyrian, TRM Oncology, Amgen, AstraZeneca, Celgene, and Agenus. Dr. Ferris has financial relationships with Bristol Myers Squibb, AstraZeneca/MedImmune, Merck, and Celgene.

The combination of nivolumab and vidutolimod led to a high rate of pathologic complete response and pathologic major response in a phase 2 trial of patients with stage 3 resectable melanoma. The result led researchers to call for a future study comparing the regimen against a suitable control group.

“We were very excited to see the ability of intratumoral vidutolimod to augment T-cell infiltrate. (Pathologic) response was associated with a dense infiltrate of CD8 T cells. We were also able to demonstrate for what I think may be the first time, that intratumoral CpG resulted in clear evidence of CD303+ plasmacytoid dendritic cells [pDCs],” said Diwakar Davar, MD, assistant professor of medicine at the University of Pittsburgh, during a presentation of the results at the annual meeting of the Society for Immunotherapy of Cancer. He noted that pDCs represent a very rare cell population, less than 0.4% of circulating peripheral blood mononuclear cells, and tend to be found in lymph nodes.

The current standard of care for stage 3 melanoma is up-front surgery followed by adjuvant therapy – anti–PD-1 therapy for patients with wild-type or BRAF-mutant cancers, and targeted therapy with BRAF/MEK inhibitors in patients with BRAF mutations. However, preclinical studies suggest that neoadjuvant immunotherapy could lead to a stronger antitumor T-cell response than adjuvant immunotherapy.

Vidutolimod targets the toll-like receptor 9 (TLR-9) endosomal receptor found in B cells and pDC cells. The formulation is a virus-like particle (VLP) that contains unmethylated cytosine guanine–rich oligonucleotides (CpG ODN). Bacterial and viral genomes tend to be enriched in CpG ODN, and this acts as a TLR-9 agonist. TLR-9 activation in turn triggers an interferon response, and this may help overcome PD-1 blockade resistance in metastatic melanoma.

The researchers conducted a nonrandomized, open-label trial that included 30 patients with stage 3 melanoma (14 women; median age, 61 years). Patients received neoadjuvant nivolumab and vidutolimod for 8 weeks, then were evaluated for surgery. Patients continued both drugs in the adjuvant setting for 48 weeks. 47% experienced complete pathologic response, 10% a major pathologic response, and 10% a partial pathologic response.

Analysis of resected samples revealed clear evidence of an immune response, Dr. Davar said during a press conference held in advance of the meeting. “Pathologic response was associated with compelling evidence of immune activation both peripherally and within the tumor, with clear evidence of pDC infiltrate and pDC activation – something that has not previously been seen in human specimens.”

The study regimen appeared safe, with no dose-limiting toxicities or grade 4 or 5 adverse events. He noted that the regimen is now being tested in the phase 2 ECOG-ACRIN trial.

The results are “very exciting,” said Pamela Ohashi, PhD, who commented on the study during the press conference. The virus-like nature of vidutolimod may be an important element of the therapy. “I think scientifically we would have predicted that the VLP carrying the CPG would be very good at activating the CD8 cells, which in fact is what you’re seeing. So I think it’s very exciting and has lots of potential for future combinations,” said Dr. Ohashi, who is director of the tumor immunotherapy program at the Princess Margaret Cancer Centre, Toronto.

The study was funded by Checkmate Pharmaceuticals. Dr. Davar has financial relationships with Checkmate Pharmaceuticals and Regeneron, which has acquired Checkmate Pharmaceuticals.

The combination of nivolumab and vidutolimod led to a high rate of pathologic complete response and pathologic major response in a phase 2 trial of patients with stage 3 resectable melanoma. The result led researchers to call for a future study comparing the regimen against a suitable control group.

“We were very excited to see the ability of intratumoral vidutolimod to augment T-cell infiltrate. (Pathologic) response was associated with a dense infiltrate of CD8 T cells. We were also able to demonstrate for what I think may be the first time, that intratumoral CpG resulted in clear evidence of CD303+ plasmacytoid dendritic cells [pDCs],” said Diwakar Davar, MD, assistant professor of medicine at the University of Pittsburgh, during a presentation of the results at the annual meeting of the Society for Immunotherapy of Cancer. He noted that pDCs represent a very rare cell population, less than 0.4% of circulating peripheral blood mononuclear cells, and tend to be found in lymph nodes.

The current standard of care for stage 3 melanoma is up-front surgery followed by adjuvant therapy – anti–PD-1 therapy for patients with wild-type or BRAF-mutant cancers, and targeted therapy with BRAF/MEK inhibitors in patients with BRAF mutations. However, preclinical studies suggest that neoadjuvant immunotherapy could lead to a stronger antitumor T-cell response than adjuvant immunotherapy.

Vidutolimod targets the toll-like receptor 9 (TLR-9) endosomal receptor found in B cells and pDC cells. The formulation is a virus-like particle (VLP) that contains unmethylated cytosine guanine–rich oligonucleotides (CpG ODN). Bacterial and viral genomes tend to be enriched in CpG ODN, and this acts as a TLR-9 agonist. TLR-9 activation in turn triggers an interferon response, and this may help overcome PD-1 blockade resistance in metastatic melanoma.

The researchers conducted a nonrandomized, open-label trial that included 30 patients with stage 3 melanoma (14 women; median age, 61 years). Patients received neoadjuvant nivolumab and vidutolimod for 8 weeks, then were evaluated for surgery. Patients continued both drugs in the adjuvant setting for 48 weeks. 47% experienced complete pathologic response, 10% a major pathologic response, and 10% a partial pathologic response.

Analysis of resected samples revealed clear evidence of an immune response, Dr. Davar said during a press conference held in advance of the meeting. “Pathologic response was associated with compelling evidence of immune activation both peripherally and within the tumor, with clear evidence of pDC infiltrate and pDC activation – something that has not previously been seen in human specimens.”

The study regimen appeared safe, with no dose-limiting toxicities or grade 4 or 5 adverse events. He noted that the regimen is now being tested in the phase 2 ECOG-ACRIN trial.

The results are “very exciting,” said Pamela Ohashi, PhD, who commented on the study during the press conference. The virus-like nature of vidutolimod may be an important element of the therapy. “I think scientifically we would have predicted that the VLP carrying the CPG would be very good at activating the CD8 cells, which in fact is what you’re seeing. So I think it’s very exciting and has lots of potential for future combinations,” said Dr. Ohashi, who is director of the tumor immunotherapy program at the Princess Margaret Cancer Centre, Toronto.

The study was funded by Checkmate Pharmaceuticals. Dr. Davar has financial relationships with Checkmate Pharmaceuticals and Regeneron, which has acquired Checkmate Pharmaceuticals.

The combination of nivolumab and vidutolimod led to a high rate of pathologic complete response and pathologic major response in a phase 2 trial of patients with stage 3 resectable melanoma. The result led researchers to call for a future study comparing the regimen against a suitable control group.

“We were very excited to see the ability of intratumoral vidutolimod to augment T-cell infiltrate. (Pathologic) response was associated with a dense infiltrate of CD8 T cells. We were also able to demonstrate for what I think may be the first time, that intratumoral CpG resulted in clear evidence of CD303+ plasmacytoid dendritic cells [pDCs],” said Diwakar Davar, MD, assistant professor of medicine at the University of Pittsburgh, during a presentation of the results at the annual meeting of the Society for Immunotherapy of Cancer. He noted that pDCs represent a very rare cell population, less than 0.4% of circulating peripheral blood mononuclear cells, and tend to be found in lymph nodes.

The current standard of care for stage 3 melanoma is up-front surgery followed by adjuvant therapy – anti–PD-1 therapy for patients with wild-type or BRAF-mutant cancers, and targeted therapy with BRAF/MEK inhibitors in patients with BRAF mutations. However, preclinical studies suggest that neoadjuvant immunotherapy could lead to a stronger antitumor T-cell response than adjuvant immunotherapy.

Vidutolimod targets the toll-like receptor 9 (TLR-9) endosomal receptor found in B cells and pDC cells. The formulation is a virus-like particle (VLP) that contains unmethylated cytosine guanine–rich oligonucleotides (CpG ODN). Bacterial and viral genomes tend to be enriched in CpG ODN, and this acts as a TLR-9 agonist. TLR-9 activation in turn triggers an interferon response, and this may help overcome PD-1 blockade resistance in metastatic melanoma.

The researchers conducted a nonrandomized, open-label trial that included 30 patients with stage 3 melanoma (14 women; median age, 61 years). Patients received neoadjuvant nivolumab and vidutolimod for 8 weeks, then were evaluated for surgery. Patients continued both drugs in the adjuvant setting for 48 weeks. 47% experienced complete pathologic response, 10% a major pathologic response, and 10% a partial pathologic response.

Analysis of resected samples revealed clear evidence of an immune response, Dr. Davar said during a press conference held in advance of the meeting. “Pathologic response was associated with compelling evidence of immune activation both peripherally and within the tumor, with clear evidence of pDC infiltrate and pDC activation – something that has not previously been seen in human specimens.”

The study regimen appeared safe, with no dose-limiting toxicities or grade 4 or 5 adverse events. He noted that the regimen is now being tested in the phase 2 ECOG-ACRIN trial.

The results are “very exciting,” said Pamela Ohashi, PhD, who commented on the study during the press conference. The virus-like nature of vidutolimod may be an important element of the therapy. “I think scientifically we would have predicted that the VLP carrying the CPG would be very good at activating the CD8 cells, which in fact is what you’re seeing. So I think it’s very exciting and has lots of potential for future combinations,” said Dr. Ohashi, who is director of the tumor immunotherapy program at the Princess Margaret Cancer Centre, Toronto.

The study was funded by Checkmate Pharmaceuticals. Dr. Davar has financial relationships with Checkmate Pharmaceuticals and Regeneron, which has acquired Checkmate Pharmaceuticals.

In advanced and metastatic melanoma patients, fecal microbiota transplant (FMT) from healthy donors in advance of anti–PD-1 immunotherapy led to a 75% clinical benefit rate, defined as complete response, partial response, or stable disease that lasted 6 months or longer. The results come from a small, single arm phase 1 study whose primary endpoint was safety.

“We know that the gut microbiome has shown the ability to affect the systemic antitumor immunity by affecting the CD8+ T cells and CD4+ T cells, and these are the cells that are ultimately important for the function of checkpoint inhibitors. There is now clinical evidence that has shown that changing patient microbiota via fecal microbiota transplantation using stool from previous responder patients has the capacity to sensitize immunotherapy refractory melanomas to anti–PD-1 therapy, (with) about 30% response in this setting,” said Saman Maleki, PhD, during his presentation of the results at the Society for Immunotherapy of Cancer’s 37th Annual Meeting. He also noted that broad-spectrum antibiotics have been shown to negatively influence responses to immunotherapy.

Rather than using stool from donors who responded to immunotherapy, the researchers chose instead to use stool from healthy donors.

The study included 20 patients with advanced melanoma who had not been treated with anti–PD-1 therapy. The median age was 75.5 years, 40% were female, and 75% had wild type BRAF. All patients underwent bowel prep and then received fecal transplants from healthy donors, followed by a 7-day engraftment period before initiating anti–PD-1 therapy in the form of nivolumab or pembrolizumab.

The primary endpoint of the study was safety, and no grade 3 or 4 toxicities were observed during the FMT, and safety signals associated with anti–PD-1 therapies were in line with previous experience.

Fifteen percent of patients had a complete response, 50% had a partial response, 15% had stable disease, and 20% had progressive disease. Seventy-five percent of patients had a complete response, partial response, or stable disease that lasted at least 6 months.

Analysis of the microbiomes showed much higher diversity in the donor microbiomes than in patients. “What was really interesting was that the success of engraftment and retention of the donor microbiome was really key in determining between responders and nonresponders. Responders had successful engraftment that lasted over time, and in nonresponders we did not see that,” said Dr. Maleki, who is a cancer immunology researcher at the University of Western Ontario, London.

They also saw differences between responders and nonresponders in how their microbiome evolved over time. Responders had enrichment in Ruminococcus callidus and other bacteria, while nonresponders had enrichment in different bacteria, among them Catabacter hongkongensis, which has previously been implicated as negatively impacting anti–PD-1 responses, according to Dr. Maleki.

Microbiomes from healthy donors had greater diversity than the patients. Following FMT, patients’ microbiomes increased regardless of clinical response to immunotherapy. However, the tendency for patients to trend toward and retain greater diversity over time was associated with treatment success. “What we saw that was key in patients’ response to immunotherapy was the ability of the patients to retain the donor microbiome. All patients’ microbiomes changed and shifted toward the donors’ post FMT. However, only the responders were able to keep the donor microbiome over time, and the nonresponders’ microbiomes reverted to the previous microbiome,” Dr. Maleki said.

The researchers also conducted a mouse version of the clinical trial. They transplanted mice with the baseline fecal samples of a human responder and then exposed the animals to tumors. They then conducted a second FMT with stool from the human donor, and the animals then responded to anti–PD-1 therapy. The results further confirm “that the donor still has the capacity to drive response in this setting,” Dr. Maleki said.

Dr. Maleki is a board member of IMV Inc.

In advanced and metastatic melanoma patients, fecal microbiota transplant (FMT) from healthy donors in advance of anti–PD-1 immunotherapy led to a 75% clinical benefit rate, defined as complete response, partial response, or stable disease that lasted 6 months or longer. The results come from a small, single arm phase 1 study whose primary endpoint was safety.

“We know that the gut microbiome has shown the ability to affect the systemic antitumor immunity by affecting the CD8+ T cells and CD4+ T cells, and these are the cells that are ultimately important for the function of checkpoint inhibitors. There is now clinical evidence that has shown that changing patient microbiota via fecal microbiota transplantation using stool from previous responder patients has the capacity to sensitize immunotherapy refractory melanomas to anti–PD-1 therapy, (with) about 30% response in this setting,” said Saman Maleki, PhD, during his presentation of the results at the Society for Immunotherapy of Cancer’s 37th Annual Meeting. He also noted that broad-spectrum antibiotics have been shown to negatively influence responses to immunotherapy.

Rather than using stool from donors who responded to immunotherapy, the researchers chose instead to use stool from healthy donors.

The study included 20 patients with advanced melanoma who had not been treated with anti–PD-1 therapy. The median age was 75.5 years, 40% were female, and 75% had wild type BRAF. All patients underwent bowel prep and then received fecal transplants from healthy donors, followed by a 7-day engraftment period before initiating anti–PD-1 therapy in the form of nivolumab or pembrolizumab.

The primary endpoint of the study was safety, and no grade 3 or 4 toxicities were observed during the FMT, and safety signals associated with anti–PD-1 therapies were in line with previous experience.

Fifteen percent of patients had a complete response, 50% had a partial response, 15% had stable disease, and 20% had progressive disease. Seventy-five percent of patients had a complete response, partial response, or stable disease that lasted at least 6 months.

Analysis of the microbiomes showed much higher diversity in the donor microbiomes than in patients. “What was really interesting was that the success of engraftment and retention of the donor microbiome was really key in determining between responders and nonresponders. Responders had successful engraftment that lasted over time, and in nonresponders we did not see that,” said Dr. Maleki, who is a cancer immunology researcher at the University of Western Ontario, London.

They also saw differences between responders and nonresponders in how their microbiome evolved over time. Responders had enrichment in Ruminococcus callidus and other bacteria, while nonresponders had enrichment in different bacteria, among them Catabacter hongkongensis, which has previously been implicated as negatively impacting anti–PD-1 responses, according to Dr. Maleki.

Microbiomes from healthy donors had greater diversity than the patients. Following FMT, patients’ microbiomes increased regardless of clinical response to immunotherapy. However, the tendency for patients to trend toward and retain greater diversity over time was associated with treatment success. “What we saw that was key in patients’ response to immunotherapy was the ability of the patients to retain the donor microbiome. All patients’ microbiomes changed and shifted toward the donors’ post FMT. However, only the responders were able to keep the donor microbiome over time, and the nonresponders’ microbiomes reverted to the previous microbiome,” Dr. Maleki said.

The researchers also conducted a mouse version of the clinical trial. They transplanted mice with the baseline fecal samples of a human responder and then exposed the animals to tumors. They then conducted a second FMT with stool from the human donor, and the animals then responded to anti–PD-1 therapy. The results further confirm “that the donor still has the capacity to drive response in this setting,” Dr. Maleki said.

Dr. Maleki is a board member of IMV Inc.

In advanced and metastatic melanoma patients, fecal microbiota transplant (FMT) from healthy donors in advance of anti–PD-1 immunotherapy led to a 75% clinical benefit rate, defined as complete response, partial response, or stable disease that lasted 6 months or longer. The results come from a small, single arm phase 1 study whose primary endpoint was safety.

“We know that the gut microbiome has shown the ability to affect the systemic antitumor immunity by affecting the CD8+ T cells and CD4+ T cells, and these are the cells that are ultimately important for the function of checkpoint inhibitors. There is now clinical evidence that has shown that changing patient microbiota via fecal microbiota transplantation using stool from previous responder patients has the capacity to sensitize immunotherapy refractory melanomas to anti–PD-1 therapy, (with) about 30% response in this setting,” said Saman Maleki, PhD, during his presentation of the results at the Society for Immunotherapy of Cancer’s 37th Annual Meeting. He also noted that broad-spectrum antibiotics have been shown to negatively influence responses to immunotherapy.

Rather than using stool from donors who responded to immunotherapy, the researchers chose instead to use stool from healthy donors.

The study included 20 patients with advanced melanoma who had not been treated with anti–PD-1 therapy. The median age was 75.5 years, 40% were female, and 75% had wild type BRAF. All patients underwent bowel prep and then received fecal transplants from healthy donors, followed by a 7-day engraftment period before initiating anti–PD-1 therapy in the form of nivolumab or pembrolizumab.

The primary endpoint of the study was safety, and no grade 3 or 4 toxicities were observed during the FMT, and safety signals associated with anti–PD-1 therapies were in line with previous experience.

Fifteen percent of patients had a complete response, 50% had a partial response, 15% had stable disease, and 20% had progressive disease. Seventy-five percent of patients had a complete response, partial response, or stable disease that lasted at least 6 months.

Analysis of the microbiomes showed much higher diversity in the donor microbiomes than in patients. “What was really interesting was that the success of engraftment and retention of the donor microbiome was really key in determining between responders and nonresponders. Responders had successful engraftment that lasted over time, and in nonresponders we did not see that,” said Dr. Maleki, who is a cancer immunology researcher at the University of Western Ontario, London.

They also saw differences between responders and nonresponders in how their microbiome evolved over time. Responders had enrichment in Ruminococcus callidus and other bacteria, while nonresponders had enrichment in different bacteria, among them Catabacter hongkongensis, which has previously been implicated as negatively impacting anti–PD-1 responses, according to Dr. Maleki.

Microbiomes from healthy donors had greater diversity than the patients. Following FMT, patients’ microbiomes increased regardless of clinical response to immunotherapy. However, the tendency for patients to trend toward and retain greater diversity over time was associated with treatment success. “What we saw that was key in patients’ response to immunotherapy was the ability of the patients to retain the donor microbiome. All patients’ microbiomes changed and shifted toward the donors’ post FMT. However, only the responders were able to keep the donor microbiome over time, and the nonresponders’ microbiomes reverted to the previous microbiome,” Dr. Maleki said.

The researchers also conducted a mouse version of the clinical trial. They transplanted mice with the baseline fecal samples of a human responder and then exposed the animals to tumors. They then conducted a second FMT with stool from the human donor, and the animals then responded to anti–PD-1 therapy. The results further confirm “that the donor still has the capacity to drive response in this setting,” Dr. Maleki said.

Dr. Maleki is a board member of IMV Inc.

In a phase 2 clinical trial of the soluble lymphocyte-activation gene 3 (LAG-3) as a potential treatment for non–small cell lung cancer (NSCLC), the drug performed well across all levels of PD-L1 expression.

“We observed a very encouraging response rate. Responses were seen across PD-L1 status,” said Wade Iams, MD, at a press conference held in advance of the annual meeting of the Society for Immunotherapy of Cancer. Dr. Iams is a professor of medicine at Vanderbilt University Medical Center, Nashville, Tenn.

“The study was not loaded to PD-L1–high patients. We had a good breakdown across all of our three typical groups in the [NSCLC] treatment setting. Across histology types between squamous and nonsquamous, the median duration of response was almost 22 months. This is very encouraging compared to historical controls,” he said.

Eftilagimod alpha is a soluble form of the LAG-3 protein, which is a stimulator of antigen-presenting cells and CD8+ T cells through its action on MHC class 2 molecules. It suppresses the activation of T cells and therefore has the potential to boost the effect of anti–PD-1 therapy. LAG-3 can have both stimulatory and inhibitor immune effects, leading Immutep, which sponsored the study with Merck Sharp and Dohme, to pursue it in both cancer immunotherapy and autoimmune diseases.

The drug is a departure from other drugs which are LAG-3 antagonists. Those therapies interfere with the interaction between LAG-3 on the surface of activated T cells and MHC class 2 molecules on the surface of resting dendritic cells, which would otherwise dampen immune response in the tumor microenvironment. On the other hand, LAG-3 (or eftilagimod alpha) interacts with MHC class 2 on the surface of activated dendritic cells and monocytes to stimulate production of cytotoxic CD8+ T cells. These in turn can be unleashed further by the downstream action of pembrolizumab.

The phase 2 trial included three parts: In part A, 114 patients with NSCLC received the combination of eftilagimod alpha and pembrolizumab being given as a first-line therapy. Part B looked at the combination in 36 patents who were resistant to PD-1/PD-L1 therapies. Part C included 39 patients with head and neck squamous cell carcinoma who had previously received platinum-based chemotherapy. Patients received combination therapy for up to 1 year, then monotherapy with pembrolizumab for up to another year.

The primary endpoint of the study was a comparison of overall response rate to historical controls, with success set at 35% or higher. In the intent-to-treat analysis of the treatment-naive NSCLC population, ORR was 39.5% (95% confidence interval, 30.5%-49.1%) and the interim median progression-free survival was 6.9 months (95% CI, 4.9-9.3 months). Among 40 responders, the median duration of response was 21.6 months (95% CI, 17.3-30.0 months). ORRs were similar between squamous and nonsquamous subtypes.

In his presentation of the results, Dr. Iams said that 75% of participants had PD-L1 levels below 50%. The ORR was highest at 55% in the PD-L1 greater than 50% group, 44.7% in the PD-L1 1%-49% group, and 31.1% in the PD-L1 less than 1% group. It was a “very impressive response rate” for the low PD-L1 group, Dr. Iams said. Interim median progression-free survival followed a similar trend, with values of 11.4 months, 8.3 months, and 4.2 months, respectively.

Asked about the efficacy across subgroups, Dr. Iams responded that other immune stimulating agents have shown a stepwise improvement across PD-L1 expression levels, similar to what was observed in the current study. “My personal opinion as to why it was still effective at low PD-L1 is in part that PD-L1 is an imperfect biomarker. We know that there’s tumor heterogeneity, and perhaps it’s not fully representative of a one-site evaluation, but also in combination, and we have seen this in patients with [NSCLC] treated with both PD-L1 and CTLA-4 agents of increased efficacy in the PD-L1–low patients. So these combination immunotherapy strategies may be uniquely opportune for the low PD-L1 patients,” Dr. Iams said.

The study was funded by Immutep and Merck Sharp and Dohme. Dr. Iams has financial relationships with Merck.

In a phase 2 clinical trial of the soluble lymphocyte-activation gene 3 (LAG-3) as a potential treatment for non–small cell lung cancer (NSCLC), the drug performed well across all levels of PD-L1 expression.

“We observed a very encouraging response rate. Responses were seen across PD-L1 status,” said Wade Iams, MD, at a press conference held in advance of the annual meeting of the Society for Immunotherapy of Cancer. Dr. Iams is a professor of medicine at Vanderbilt University Medical Center, Nashville, Tenn.

“The study was not loaded to PD-L1–high patients. We had a good breakdown across all of our three typical groups in the [NSCLC] treatment setting. Across histology types between squamous and nonsquamous, the median duration of response was almost 22 months. This is very encouraging compared to historical controls,” he said.

Eftilagimod alpha is a soluble form of the LAG-3 protein, which is a stimulator of antigen-presenting cells and CD8+ T cells through its action on MHC class 2 molecules. It suppresses the activation of T cells and therefore has the potential to boost the effect of anti–PD-1 therapy. LAG-3 can have both stimulatory and inhibitor immune effects, leading Immutep, which sponsored the study with Merck Sharp and Dohme, to pursue it in both cancer immunotherapy and autoimmune diseases.

The drug is a departure from other drugs which are LAG-3 antagonists. Those therapies interfere with the interaction between LAG-3 on the surface of activated T cells and MHC class 2 molecules on the surface of resting dendritic cells, which would otherwise dampen immune response in the tumor microenvironment. On the other hand, LAG-3 (or eftilagimod alpha) interacts with MHC class 2 on the surface of activated dendritic cells and monocytes to stimulate production of cytotoxic CD8+ T cells. These in turn can be unleashed further by the downstream action of pembrolizumab.

The phase 2 trial included three parts: In part A, 114 patients with NSCLC received the combination of eftilagimod alpha and pembrolizumab being given as a first-line therapy. Part B looked at the combination in 36 patents who were resistant to PD-1/PD-L1 therapies. Part C included 39 patients with head and neck squamous cell carcinoma who had previously received platinum-based chemotherapy. Patients received combination therapy for up to 1 year, then monotherapy with pembrolizumab for up to another year.

The primary endpoint of the study was a comparison of overall response rate to historical controls, with success set at 35% or higher. In the intent-to-treat analysis of the treatment-naive NSCLC population, ORR was 39.5% (95% confidence interval, 30.5%-49.1%) and the interim median progression-free survival was 6.9 months (95% CI, 4.9-9.3 months). Among 40 responders, the median duration of response was 21.6 months (95% CI, 17.3-30.0 months). ORRs were similar between squamous and nonsquamous subtypes.

In his presentation of the results, Dr. Iams said that 75% of participants had PD-L1 levels below 50%. The ORR was highest at 55% in the PD-L1 greater than 50% group, 44.7% in the PD-L1 1%-49% group, and 31.1% in the PD-L1 less than 1% group. It was a “very impressive response rate” for the low PD-L1 group, Dr. Iams said. Interim median progression-free survival followed a similar trend, with values of 11.4 months, 8.3 months, and 4.2 months, respectively.

Asked about the efficacy across subgroups, Dr. Iams responded that other immune stimulating agents have shown a stepwise improvement across PD-L1 expression levels, similar to what was observed in the current study. “My personal opinion as to why it was still effective at low PD-L1 is in part that PD-L1 is an imperfect biomarker. We know that there’s tumor heterogeneity, and perhaps it’s not fully representative of a one-site evaluation, but also in combination, and we have seen this in patients with [NSCLC] treated with both PD-L1 and CTLA-4 agents of increased efficacy in the PD-L1–low patients. So these combination immunotherapy strategies may be uniquely opportune for the low PD-L1 patients,” Dr. Iams said.

The study was funded by Immutep and Merck Sharp and Dohme. Dr. Iams has financial relationships with Merck.

In a phase 2 clinical trial of the soluble lymphocyte-activation gene 3 (LAG-3) as a potential treatment for non–small cell lung cancer (NSCLC), the drug performed well across all levels of PD-L1 expression.

“We observed a very encouraging response rate. Responses were seen across PD-L1 status,” said Wade Iams, MD, at a press conference held in advance of the annual meeting of the Society for Immunotherapy of Cancer. Dr. Iams is a professor of medicine at Vanderbilt University Medical Center, Nashville, Tenn.

“The study was not loaded to PD-L1–high patients. We had a good breakdown across all of our three typical groups in the [NSCLC] treatment setting. Across histology types between squamous and nonsquamous, the median duration of response was almost 22 months. This is very encouraging compared to historical controls,” he said.

Eftilagimod alpha is a soluble form of the LAG-3 protein, which is a stimulator of antigen-presenting cells and CD8+ T cells through its action on MHC class 2 molecules. It suppresses the activation of T cells and therefore has the potential to boost the effect of anti–PD-1 therapy. LAG-3 can have both stimulatory and inhibitor immune effects, leading Immutep, which sponsored the study with Merck Sharp and Dohme, to pursue it in both cancer immunotherapy and autoimmune diseases.

The drug is a departure from other drugs which are LAG-3 antagonists. Those therapies interfere with the interaction between LAG-3 on the surface of activated T cells and MHC class 2 molecules on the surface of resting dendritic cells, which would otherwise dampen immune response in the tumor microenvironment. On the other hand, LAG-3 (or eftilagimod alpha) interacts with MHC class 2 on the surface of activated dendritic cells and monocytes to stimulate production of cytotoxic CD8+ T cells. These in turn can be unleashed further by the downstream action of pembrolizumab.

The phase 2 trial included three parts: In part A, 114 patients with NSCLC received the combination of eftilagimod alpha and pembrolizumab being given as a first-line therapy. Part B looked at the combination in 36 patents who were resistant to PD-1/PD-L1 therapies. Part C included 39 patients with head and neck squamous cell carcinoma who had previously received platinum-based chemotherapy. Patients received combination therapy for up to 1 year, then monotherapy with pembrolizumab for up to another year.

The primary endpoint of the study was a comparison of overall response rate to historical controls, with success set at 35% or higher. In the intent-to-treat analysis of the treatment-naive NSCLC population, ORR was 39.5% (95% confidence interval, 30.5%-49.1%) and the interim median progression-free survival was 6.9 months (95% CI, 4.9-9.3 months). Among 40 responders, the median duration of response was 21.6 months (95% CI, 17.3-30.0 months). ORRs were similar between squamous and nonsquamous subtypes.

In his presentation of the results, Dr. Iams said that 75% of participants had PD-L1 levels below 50%. The ORR was highest at 55% in the PD-L1 greater than 50% group, 44.7% in the PD-L1 1%-49% group, and 31.1% in the PD-L1 less than 1% group. It was a “very impressive response rate” for the low PD-L1 group, Dr. Iams said. Interim median progression-free survival followed a similar trend, with values of 11.4 months, 8.3 months, and 4.2 months, respectively.

Asked about the efficacy across subgroups, Dr. Iams responded that other immune stimulating agents have shown a stepwise improvement across PD-L1 expression levels, similar to what was observed in the current study. “My personal opinion as to why it was still effective at low PD-L1 is in part that PD-L1 is an imperfect biomarker. We know that there’s tumor heterogeneity, and perhaps it’s not fully representative of a one-site evaluation, but also in combination, and we have seen this in patients with [NSCLC] treated with both PD-L1 and CTLA-4 agents of increased efficacy in the PD-L1–low patients. So these combination immunotherapy strategies may be uniquely opportune for the low PD-L1 patients,” Dr. Iams said.

The study was funded by Immutep and Merck Sharp and Dohme. Dr. Iams has financial relationships with Merck.

A woman who had breast cancer for 23 years, and who had gone through 12 different lines of therapy, has shown a dramatic response to a novel cancer vaccine in a clinical trial.

A recent 6-month follow-up showed no evidence of new or recurrent disease, and scans showed regression of a distant bulky left adrenal metastasis, as well as at other sites.

A small site of residual hypermetabolism remains in the sternum, but this is thought to be related to scar tissue.

The patient, Stephanie Gangi, told Medscape Medical News that, before she entered into the trial for the novel cancer vaccine, she was “mentally and physically exhausted.” She had benefited from being diagnosed with hormone-positive breast cancer just as its treatment was evolving and progressing, which meant that, every time a treatment failed, “there was the next thing to try, which was great and kept me going.”

“But I will admit that, by age 66, and more than 20 years of cancer treatments, I was exhausted.”

Ms. Gangi, a New York City-based poet, essayist, and fiction writer, said she was “cautiously optimistic” about the cancer vaccine, but the “overriding thought was I wanted to avoid chemotherapy.”

“I was not really signing on for great outcomes, I was signing on for something that might keep chemo at bay. The biggest impact so far for me has been that, for the first time in more than a decade, I am not on any medication. That’s really amazing…and that means no side effects,” she said.

Ms. Gangi stopped the vaccine treatment this past July, and just over 3 months later, she is still “wrapping her head around” the fact that her cancer has regressed. “I’ve had breast cancer a long time,” she said, “and you can’t just snap your fingers and be fine.”

Although the two scans that she has had since the trial ended have been “astonishing,” she underlined that this is not about a ‘cure,’ but rather “clearing tumors for the first time in many years.”

“Cancer is sneaky and sinister, and it figures out how to circumvent all kinds of treatments,” she said, adding nevertheless that she is “happy and hopeful, and my family is thrilled, of course.”

Ms. Gangi was classed as having had a partial response to the cancer vaccine, one of a few in a small phase 1/2 trial at the Icahn School of Medicine at Mount Sinai in New York. One other patient also had a partial response, and one patient had a complete response.

However, six patients have progressive disease, and one has stable disease.  

These results come from an interim analysis of 10 patients from the trial, and show a 30% response rate. They were presented at the recent annual meeting of the Society for Immunotherapy of Cancer.

The vaccine that was being tested combines local low-dose radiation, intramural Flt3L, which stimulates dendritic cells, and intravenous poly-ICLC, an immune stimulating factor, with the PD-1 inhibitor pembrolizumab (Keytruda).

The result is that, instead of making a vaccine in a laboratory and administering it, “we’re actually formulating it within the body,” lead author Thomas Marron, MD, PhD, professor of medicine (hematology and medical oncology) at Mount Sinai, said in an interview.

“What people don’t realize,” he said, is that bulky tumor sites contain “a lot of dead tumor, because they grow so fast and in a haphazard way.” This means that the immune system can be recruited to recognize the dead tumor and “gobble up the dead stuff that’s already there,” he added.

The hope is that the immune system will then kill not only “the tumor you are injecting into, but also tumors elsewhere in the body,” Dr. Marron said. “So you’re basically using your body’s own immune system and on and off switches to vaccinate the patient against their cancer.”

Another patient in the trial who had a complete response to the vaccine was William Morrison, with non-Hodgkin lymphoma (NHL).

Mr. Morrison was diagnosed in 2017, at which time he was enrolled onto a phase 1 trial of an earlier version of this novel vaccine treatment regimen. “Basically, they didn’t get the results they were hoping for, and I still had the lymphoma,” he said. In 2018, his indolent follicular lymphoma transformed into an aggressive diffuse large B-cell lymphoma, for which Mr. Morrison was given six cycles of chemotherapy. This put him into remission and cleared his lymphoma.

“But the remission lasted for maybe a little over a year,” he said.

The cancer came back, and at that point he was given the opportunity to enroll in the Mount Sinai trial. At the end of the treatment, “everything was clear.”

“I’ve been for PET scans every 6 months, and I just had a scan done the other week, and everything has been fine…I’ve been pretty excited. I was pretty lucky.”

“This recent one really has worked wonders,” he said, “When they gave me the good news the other day. I felt like a big weight had been lifted.”

Mr. Morrison also said that he did not experience any serious adverse events while being treated with the vaccine. “Other than a few minor things, I tolerated it pretty well,” he said.

In contrast, Ms. Gangi said she experienced “intense” flu-like symptoms that started in the first few days after the treatment and lasted for a couple of days.
 

Need to improve response rate

The current trial achieved responses in 30% of patients, which “is great, [but] we want to be at 100%,” said Dr. Marron.

“What we’re doing in the laboratory right now is using this as an opportunity to study what it is that’s special about those three people who responded and what’s not happening in the other seven people, and we have some initial data that we’re analyzing,” he said.

“We are seeing that the patients who responded have a much more robust response to the Ft3L in particular…and that could suggest that maybe we need a better Ft3L, or we could think about other ways to potentially manipulate this vaccine.

“Most of the patients who are referred to me are people who have run out of options…and that usually means they’ve had many different types of chemotherapy,” Dr. Marron commented. For example, Ms. Gangi had already been through 12 different chemotherapy regimens.

Chemotherapy suppresses the immune system, but it’s not only that — also having an effect are all the other treatments aimed at reducing nausea and allergic reactions to the anti-cancer therapy, Dr. Marron explained.

“By the time that I see a patient,” Dr. Marron said, “oftentimes their immune system is not optimal. So another way in which we would hope to see better responses is by moving this vaccine earlier in the treatment paradigm, and administering it to patients as their first or second treatment.”

Senior author Joshua Brody, MD, director of the Lymphoma Immunotherapy Program at Mount Sinai’s Tisch Cancer Institute, added that it “might be easy” to incorporate the vaccine into earlier lines of therapy.

He said in an interview that both immunotherapy and radiation therapy are “standard” treatments, and the key is “adding multiple ingredients together that don’t have cumulative toxicity.”

“You can’t just chemo one plus chemo two, because they have some of the same toxicities, but the delightful thing here is this therapy had been quite safe.

“So in theory it would be fairly easy to incorporate this into earlier lines of therapy, once we can get a bit more proof of principle,” Dr. Brody said.

Approached for comment, Ann W. Silk, MD, said that the results are “particularly impressive because we know anti-PD-1 plus radiation therapy does not work in hormone-positive breast cancer or lymphoma.”

Dr. Silk, an oncologist at the Dana-Farber Cancer Institute and assistant professor of medicine at Harvard Medical School in Boston, said in an interview that one advantage of this vaccine is that it “is not restricted to a certain number of antigens and does not rely on an algorithm.”

“I would love to see more data in hormone-positive metastatic breast cancer patients,” she added. “I would use this approach after the hormonal treatments stop working, but before chemotherapy.”

Dr. Silk also said that the safety profile “looks quite good, and I imagine this approach would result in a much better quality of life for patients as compared to chemotherapy.”
 

Details of the trial and results

The Mount Sinai researchers had previously developed a personalized genomic cancer vaccine, PGV-001, which showed promise in a phase 1 trial in 13 patients with solid tumors or multiple myeloma and a high risk of recurrence after surgery or autologous stem cell transplant.

Next, they worked to develop the concept further to turn the tumor into its own vaccine, which involved inducing anti-tumor responses in indolent NHL, which typically responds poorly to checkpoint blockade, by combining Ft3L, low-dose irradiation, and poly-ICLC.

The next phase 1 trial showed that this approach was feasible, but preclinical modeling suggested that the addition of PD-1 blockade could improve the cure rates. The researchers therefore conducted the current trial, recruiting 10 patients with indolent NHL, metastatic breast cancer, or head and neck squamous cell carcinoma (HNSCC).

Patients were given local radiation therapy on days 1 and 2, and intramural Ft3L to the same tumor on day 9, followed by eight intravenous injections of poly-ICLC over 6 weeks. On day 23, they received their first of eight doses of pembrolizumab.

Dr. Marron explained that the radiotherapy increases the amount of dead material for the immune system to work on by “killing some of the tumor cells,” adding: “We’re not trying to kill the whole tumor with the radiation…it just starts the process of releasing some more of that dead stuff.”

He explained that Ft3L is a human growth factor that simulates dendritic cells, “which I always say are the professor cells of the immune system,” as they tell the body “what’s good and what’s bad.”

The poly-ICLC is “basically like a fake virus,” Dr. Marron said, as it “turns on those immune cells that have taken up the tumor antigen in the neighborhood” of the tumor, so they “teach the immune system that there is something bad”.

Finally, the pembrolizumab is there to “take the foot off the brake of the immune system” and “grease the wheels a bit more,” he added, even though it does not work in all patients, or in all tumor types, including indolent NHL.

The trial was planned in two phases. In the first part, six patients were enrolled to assess the safety of the approach; the phase 2 stage of the trial followed a Simon’s Two-Stage design, with the aim of recruiting seven patients of each tumor type, followed by a further 12 patients if they showed a response.

The current interim analysis that was presented at the SITC meeting focused on the first 10 patients in the phase 2 part, who were enrolled between April 2019 and July 2022. This included six patients with metastatic breast cancer, three with indolent NHL, and one with HNSCC, all of whom completed their first disease response assessment.

All patients experienced treatment-related adverse events, largely comprising low-grade injection site reactions and flu-like symptoms linked to the poly-ICLC injections.

One patient experienced grade 3 pembrolizumab-related colitis, while another had self-resolving grade 3 fever following poly-ICLC injection.

The study was sponsored by Icahn School of Medicine at Mount Sinai and conducted in collaboration with Merck Sharp & Dohme LLC and Celldex Therapeutics. No relevant financial relationships were reported.

A version of this article first appeared on Medscape.com.

A woman who had breast cancer for 23 years, and who had gone through 12 different lines of therapy, has shown a dramatic response to a novel cancer vaccine in a clinical trial.

A recent 6-month follow-up showed no evidence of new or recurrent disease, and scans showed regression of a distant bulky left adrenal metastasis, as well as at other sites.

A small site of residual hypermetabolism remains in the sternum, but this is thought to be related to scar tissue.

The patient, Stephanie Gangi, told Medscape Medical News that, before she entered into the trial for the novel cancer vaccine, she was “mentally and physically exhausted.” She had benefited from being diagnosed with hormone-positive breast cancer just as its treatment was evolving and progressing, which meant that, every time a treatment failed, “there was the next thing to try, which was great and kept me going.”

“But I will admit that, by age 66, and more than 20 years of cancer treatments, I was exhausted.”

Ms. Gangi, a New York City-based poet, essayist, and fiction writer, said she was “cautiously optimistic” about the cancer vaccine, but the “overriding thought was I wanted to avoid chemotherapy.”

“I was not really signing on for great outcomes, I was signing on for something that might keep chemo at bay. The biggest impact so far for me has been that, for the first time in more than a decade, I am not on any medication. That’s really amazing…and that means no side effects,” she said.

Ms. Gangi stopped the vaccine treatment this past July, and just over 3 months later, she is still “wrapping her head around” the fact that her cancer has regressed. “I’ve had breast cancer a long time,” she said, “and you can’t just snap your fingers and be fine.”

Although the two scans that she has had since the trial ended have been “astonishing,” she underlined that this is not about a ‘cure,’ but rather “clearing tumors for the first time in many years.”

“Cancer is sneaky and sinister, and it figures out how to circumvent all kinds of treatments,” she said, adding nevertheless that she is “happy and hopeful, and my family is thrilled, of course.”

Ms. Gangi was classed as having had a partial response to the cancer vaccine, one of a few in a small phase 1/2 trial at the Icahn School of Medicine at Mount Sinai in New York. One other patient also had a partial response, and one patient had a complete response.

However, six patients have progressive disease, and one has stable disease.  

These results come from an interim analysis of 10 patients from the trial, and show a 30% response rate. They were presented at the recent annual meeting of the Society for Immunotherapy of Cancer.

The vaccine that was being tested combines local low-dose radiation, intramural Flt3L, which stimulates dendritic cells, and intravenous poly-ICLC, an immune stimulating factor, with the PD-1 inhibitor pembrolizumab (Keytruda).

The result is that, instead of making a vaccine in a laboratory and administering it, “we’re actually formulating it within the body,” lead author Thomas Marron, MD, PhD, professor of medicine (hematology and medical oncology) at Mount Sinai, said in an interview.

“What people don’t realize,” he said, is that bulky tumor sites contain “a lot of dead tumor, because they grow so fast and in a haphazard way.” This means that the immune system can be recruited to recognize the dead tumor and “gobble up the dead stuff that’s already there,” he added.

The hope is that the immune system will then kill not only “the tumor you are injecting into, but also tumors elsewhere in the body,” Dr. Marron said. “So you’re basically using your body’s own immune system and on and off switches to vaccinate the patient against their cancer.”

Another patient in the trial who had a complete response to the vaccine was William Morrison, with non-Hodgkin lymphoma (NHL).

Mr. Morrison was diagnosed in 2017, at which time he was enrolled onto a phase 1 trial of an earlier version of this novel vaccine treatment regimen. “Basically, they didn’t get the results they were hoping for, and I still had the lymphoma,” he said. In 2018, his indolent follicular lymphoma transformed into an aggressive diffuse large B-cell lymphoma, for which Mr. Morrison was given six cycles of chemotherapy. This put him into remission and cleared his lymphoma.

“But the remission lasted for maybe a little over a year,” he said.

The cancer came back, and at that point he was given the opportunity to enroll in the Mount Sinai trial. At the end of the treatment, “everything was clear.”

“I’ve been for PET scans every 6 months, and I just had a scan done the other week, and everything has been fine…I’ve been pretty excited. I was pretty lucky.”

“This recent one really has worked wonders,” he said, “When they gave me the good news the other day. I felt like a big weight had been lifted.”

Mr. Morrison also said that he did not experience any serious adverse events while being treated with the vaccine. “Other than a few minor things, I tolerated it pretty well,” he said.

In contrast, Ms. Gangi said she experienced “intense” flu-like symptoms that started in the first few days after the treatment and lasted for a couple of days.
 

Need to improve response rate

The current trial achieved responses in 30% of patients, which “is great, [but] we want to be at 100%,” said Dr. Marron.

“What we’re doing in the laboratory right now is using this as an opportunity to study what it is that’s special about those three people who responded and what’s not happening in the other seven people, and we have some initial data that we’re analyzing,” he said.

“We are seeing that the patients who responded have a much more robust response to the Ft3L in particular…and that could suggest that maybe we need a better Ft3L, or we could think about other ways to potentially manipulate this vaccine.

“Most of the patients who are referred to me are people who have run out of options…and that usually means they’ve had many different types of chemotherapy,” Dr. Marron commented. For example, Ms. Gangi had already been through 12 different chemotherapy regimens.

Chemotherapy suppresses the immune system, but it’s not only that — also having an effect are all the other treatments aimed at reducing nausea and allergic reactions to the anti-cancer therapy, Dr. Marron explained.

“By the time that I see a patient,” Dr. Marron said, “oftentimes their immune system is not optimal. So another way in which we would hope to see better responses is by moving this vaccine earlier in the treatment paradigm, and administering it to patients as their first or second treatment.”

Senior author Joshua Brody, MD, director of the Lymphoma Immunotherapy Program at Mount Sinai’s Tisch Cancer Institute, added that it “might be easy” to incorporate the vaccine into earlier lines of therapy.

He said in an interview that both immunotherapy and radiation therapy are “standard” treatments, and the key is “adding multiple ingredients together that don’t have cumulative toxicity.”

“You can’t just chemo one plus chemo two, because they have some of the same toxicities, but the delightful thing here is this therapy had been quite safe.

“So in theory it would be fairly easy to incorporate this into earlier lines of therapy, once we can get a bit more proof of principle,” Dr. Brody said.

Approached for comment, Ann W. Silk, MD, said that the results are “particularly impressive because we know anti-PD-1 plus radiation therapy does not work in hormone-positive breast cancer or lymphoma.”

Dr. Silk, an oncologist at the Dana-Farber Cancer Institute and assistant professor of medicine at Harvard Medical School in Boston, said in an interview that one advantage of this vaccine is that it “is not restricted to a certain number of antigens and does not rely on an algorithm.”

“I would love to see more data in hormone-positive metastatic breast cancer patients,” she added. “I would use this approach after the hormonal treatments stop working, but before chemotherapy.”

Dr. Silk also said that the safety profile “looks quite good, and I imagine this approach would result in a much better quality of life for patients as compared to chemotherapy.”
 

Details of the trial and results

The Mount Sinai researchers had previously developed a personalized genomic cancer vaccine, PGV-001, which showed promise in a phase 1 trial in 13 patients with solid tumors or multiple myeloma and a high risk of recurrence after surgery or autologous stem cell transplant.

Next, they worked to develop the concept further to turn the tumor into its own vaccine, which involved inducing anti-tumor responses in indolent NHL, which typically responds poorly to checkpoint blockade, by combining Ft3L, low-dose irradiation, and poly-ICLC.

The next phase 1 trial showed that this approach was feasible, but preclinical modeling suggested that the addition of PD-1 blockade could improve the cure rates. The researchers therefore conducted the current trial, recruiting 10 patients with indolent NHL, metastatic breast cancer, or head and neck squamous cell carcinoma (HNSCC).

Patients were given local radiation therapy on days 1 and 2, and intramural Ft3L to the same tumor on day 9, followed by eight intravenous injections of poly-ICLC over 6 weeks. On day 23, they received their first of eight doses of pembrolizumab.

Dr. Marron explained that the radiotherapy increases the amount of dead material for the immune system to work on by “killing some of the tumor cells,” adding: “We’re not trying to kill the whole tumor with the radiation…it just starts the process of releasing some more of that dead stuff.”

He explained that Ft3L is a human growth factor that simulates dendritic cells, “which I always say are the professor cells of the immune system,” as they tell the body “what’s good and what’s bad.”

The poly-ICLC is “basically like a fake virus,” Dr. Marron said, as it “turns on those immune cells that have taken up the tumor antigen in the neighborhood” of the tumor, so they “teach the immune system that there is something bad”.

Finally, the pembrolizumab is there to “take the foot off the brake of the immune system” and “grease the wheels a bit more,” he added, even though it does not work in all patients, or in all tumor types, including indolent NHL.

The trial was planned in two phases. In the first part, six patients were enrolled to assess the safety of the approach; the phase 2 stage of the trial followed a Simon’s Two-Stage design, with the aim of recruiting seven patients of each tumor type, followed by a further 12 patients if they showed a response.

The current interim analysis that was presented at the SITC meeting focused on the first 10 patients in the phase 2 part, who were enrolled between April 2019 and July 2022. This included six patients with metastatic breast cancer, three with indolent NHL, and one with HNSCC, all of whom completed their first disease response assessment.

All patients experienced treatment-related adverse events, largely comprising low-grade injection site reactions and flu-like symptoms linked to the poly-ICLC injections.

One patient experienced grade 3 pembrolizumab-related colitis, while another had self-resolving grade 3 fever following poly-ICLC injection.

The study was sponsored by Icahn School of Medicine at Mount Sinai and conducted in collaboration with Merck Sharp & Dohme LLC and Celldex Therapeutics. No relevant financial relationships were reported.

A version of this article first appeared on Medscape.com.

A woman who had breast cancer for 23 years, and who had gone through 12 different lines of therapy, has shown a dramatic response to a novel cancer vaccine in a clinical trial.

A recent 6-month follow-up showed no evidence of new or recurrent disease, and scans showed regression of a distant bulky left adrenal metastasis, as well as at other sites.

A small site of residual hypermetabolism remains in the sternum, but this is thought to be related to scar tissue.

The patient, Stephanie Gangi, told Medscape Medical News that, before she entered into the trial for the novel cancer vaccine, she was “mentally and physically exhausted.” She had benefited from being diagnosed with hormone-positive breast cancer just as its treatment was evolving and progressing, which meant that, every time a treatment failed, “there was the next thing to try, which was great and kept me going.”

“But I will admit that, by age 66, and more than 20 years of cancer treatments, I was exhausted.”

Ms. Gangi, a New York City-based poet, essayist, and fiction writer, said she was “cautiously optimistic” about the cancer vaccine, but the “overriding thought was I wanted to avoid chemotherapy.”

“I was not really signing on for great outcomes, I was signing on for something that might keep chemo at bay. The biggest impact so far for me has been that, for the first time in more than a decade, I am not on any medication. That’s really amazing…and that means no side effects,” she said.

Ms. Gangi stopped the vaccine treatment this past July, and just over 3 months later, she is still “wrapping her head around” the fact that her cancer has regressed. “I’ve had breast cancer a long time,” she said, “and you can’t just snap your fingers and be fine.”

Although the two scans that she has had since the trial ended have been “astonishing,” she underlined that this is not about a ‘cure,’ but rather “clearing tumors for the first time in many years.”

“Cancer is sneaky and sinister, and it figures out how to circumvent all kinds of treatments,” she said, adding nevertheless that she is “happy and hopeful, and my family is thrilled, of course.”

Ms. Gangi was classed as having had a partial response to the cancer vaccine, one of a few in a small phase 1/2 trial at the Icahn School of Medicine at Mount Sinai in New York. One other patient also had a partial response, and one patient had a complete response.

However, six patients have progressive disease, and one has stable disease.  

These results come from an interim analysis of 10 patients from the trial, and show a 30% response rate. They were presented at the recent annual meeting of the Society for Immunotherapy of Cancer.

The vaccine that was being tested combines local low-dose radiation, intramural Flt3L, which stimulates dendritic cells, and intravenous poly-ICLC, an immune stimulating factor, with the PD-1 inhibitor pembrolizumab (Keytruda).

The result is that, instead of making a vaccine in a laboratory and administering it, “we’re actually formulating it within the body,” lead author Thomas Marron, MD, PhD, professor of medicine (hematology and medical oncology) at Mount Sinai, said in an interview.

“What people don’t realize,” he said, is that bulky tumor sites contain “a lot of dead tumor, because they grow so fast and in a haphazard way.” This means that the immune system can be recruited to recognize the dead tumor and “gobble up the dead stuff that’s already there,” he added.

The hope is that the immune system will then kill not only “the tumor you are injecting into, but also tumors elsewhere in the body,” Dr. Marron said. “So you’re basically using your body’s own immune system and on and off switches to vaccinate the patient against their cancer.”

Another patient in the trial who had a complete response to the vaccine was William Morrison, with non-Hodgkin lymphoma (NHL).

Mr. Morrison was diagnosed in 2017, at which time he was enrolled onto a phase 1 trial of an earlier version of this novel vaccine treatment regimen. “Basically, they didn’t get the results they were hoping for, and I still had the lymphoma,” he said. In 2018, his indolent follicular lymphoma transformed into an aggressive diffuse large B-cell lymphoma, for which Mr. Morrison was given six cycles of chemotherapy. This put him into remission and cleared his lymphoma.

“But the remission lasted for maybe a little over a year,” he said.

The cancer came back, and at that point he was given the opportunity to enroll in the Mount Sinai trial. At the end of the treatment, “everything was clear.”

“I’ve been for PET scans every 6 months, and I just had a scan done the other week, and everything has been fine…I’ve been pretty excited. I was pretty lucky.”

“This recent one really has worked wonders,” he said, “When they gave me the good news the other day. I felt like a big weight had been lifted.”

Mr. Morrison also said that he did not experience any serious adverse events while being treated with the vaccine. “Other than a few minor things, I tolerated it pretty well,” he said.

In contrast, Ms. Gangi said she experienced “intense” flu-like symptoms that started in the first few days after the treatment and lasted for a couple of days.
 

Need to improve response rate

The current trial achieved responses in 30% of patients, which “is great, [but] we want to be at 100%,” said Dr. Marron.

“What we’re doing in the laboratory right now is using this as an opportunity to study what it is that’s special about those three people who responded and what’s not happening in the other seven people, and we have some initial data that we’re analyzing,” he said.

“We are seeing that the patients who responded have a much more robust response to the Ft3L in particular…and that could suggest that maybe we need a better Ft3L, or we could think about other ways to potentially manipulate this vaccine.

“Most of the patients who are referred to me are people who have run out of options…and that usually means they’ve had many different types of chemotherapy,” Dr. Marron commented. For example, Ms. Gangi had already been through 12 different chemotherapy regimens.

Chemotherapy suppresses the immune system, but it’s not only that — also having an effect are all the other treatments aimed at reducing nausea and allergic reactions to the anti-cancer therapy, Dr. Marron explained.

“By the time that I see a patient,” Dr. Marron said, “oftentimes their immune system is not optimal. So another way in which we would hope to see better responses is by moving this vaccine earlier in the treatment paradigm, and administering it to patients as their first or second treatment.”

Senior author Joshua Brody, MD, director of the Lymphoma Immunotherapy Program at Mount Sinai’s Tisch Cancer Institute, added that it “might be easy” to incorporate the vaccine into earlier lines of therapy.

He said in an interview that both immunotherapy and radiation therapy are “standard” treatments, and the key is “adding multiple ingredients together that don’t have cumulative toxicity.”

“You can’t just chemo one plus chemo two, because they have some of the same toxicities, but the delightful thing here is this therapy had been quite safe.

“So in theory it would be fairly easy to incorporate this into earlier lines of therapy, once we can get a bit more proof of principle,” Dr. Brody said.

Approached for comment, Ann W. Silk, MD, said that the results are “particularly impressive because we know anti-PD-1 plus radiation therapy does not work in hormone-positive breast cancer or lymphoma.”

Dr. Silk, an oncologist at the Dana-Farber Cancer Institute and assistant professor of medicine at Harvard Medical School in Boston, said in an interview that one advantage of this vaccine is that it “is not restricted to a certain number of antigens and does not rely on an algorithm.”

“I would love to see more data in hormone-positive metastatic breast cancer patients,” she added. “I would use this approach after the hormonal treatments stop working, but before chemotherapy.”

Dr. Silk also said that the safety profile “looks quite good, and I imagine this approach would result in a much better quality of life for patients as compared to chemotherapy.”
 

Details of the trial and results

The Mount Sinai researchers had previously developed a personalized genomic cancer vaccine, PGV-001, which showed promise in a phase 1 trial in 13 patients with solid tumors or multiple myeloma and a high risk of recurrence after surgery or autologous stem cell transplant.

Next, they worked to develop the concept further to turn the tumor into its own vaccine, which involved inducing anti-tumor responses in indolent NHL, which typically responds poorly to checkpoint blockade, by combining Ft3L, low-dose irradiation, and poly-ICLC.

The next phase 1 trial showed that this approach was feasible, but preclinical modeling suggested that the addition of PD-1 blockade could improve the cure rates. The researchers therefore conducted the current trial, recruiting 10 patients with indolent NHL, metastatic breast cancer, or head and neck squamous cell carcinoma (HNSCC).

Patients were given local radiation therapy on days 1 and 2, and intramural Ft3L to the same tumor on day 9, followed by eight intravenous injections of poly-ICLC over 6 weeks. On day 23, they received their first of eight doses of pembrolizumab.

Dr. Marron explained that the radiotherapy increases the amount of dead material for the immune system to work on by “killing some of the tumor cells,” adding: “We’re not trying to kill the whole tumor with the radiation…it just starts the process of releasing some more of that dead stuff.”

He explained that Ft3L is a human growth factor that simulates dendritic cells, “which I always say are the professor cells of the immune system,” as they tell the body “what’s good and what’s bad.”

The poly-ICLC is “basically like a fake virus,” Dr. Marron said, as it “turns on those immune cells that have taken up the tumor antigen in the neighborhood” of the tumor, so they “teach the immune system that there is something bad”.

Finally, the pembrolizumab is there to “take the foot off the brake of the immune system” and “grease the wheels a bit more,” he added, even though it does not work in all patients, or in all tumor types, including indolent NHL.

The trial was planned in two phases. In the first part, six patients were enrolled to assess the safety of the approach; the phase 2 stage of the trial followed a Simon’s Two-Stage design, with the aim of recruiting seven patients of each tumor type, followed by a further 12 patients if they showed a response.

The current interim analysis that was presented at the SITC meeting focused on the first 10 patients in the phase 2 part, who were enrolled between April 2019 and July 2022. This included six patients with metastatic breast cancer, three with indolent NHL, and one with HNSCC, all of whom completed their first disease response assessment.

All patients experienced treatment-related adverse events, largely comprising low-grade injection site reactions and flu-like symptoms linked to the poly-ICLC injections.

One patient experienced grade 3 pembrolizumab-related colitis, while another had self-resolving grade 3 fever following poly-ICLC injection.

The study was sponsored by Icahn School of Medicine at Mount Sinai and conducted in collaboration with Merck Sharp & Dohme LLC and Celldex Therapeutics. No relevant financial relationships were reported.

A version of this article first appeared on Medscape.com.