Challenges of the current precision medicine approach for pancreatic cancer: A single institution experience between 2013 and 2017

Recent research on genomic profiling of pancreatic ductal adenocarcinoma (PDAC) has identified many potentially actionable alterations. However, the feasibility of using genomic profiling to guide routine clinical decision making for PDAC patients remains unclear. We retrospectively reviewed PDAC patients between October 2013 and December 2017, who underwent treatment at the Johns Hopkins Hospital and had clinical tumor next-generation sequencing (NGS) through commercial resources. Ninety-two patients with 93 tumors tested were included. Forty-eight (52%) patients had potentially curative surgeries. The median time from the tissue available to the NGS testing ordered was 229 days (interquartile range 62-415). A total of three (3%) patients had matched targeted therapies based on genomic profiling results. Genomic profiling guided personalized treatment for PDAC patients is feasible, but the percentage of patients who receive targeted therapy is low. The main challenges are ordering NGS testing early in the clinical course of the disease and the limited evidence of using a targeted approach in these patients. A real-time department level genomic testing ordering system in combination with an evidence-based flagging system for potentially actionable alterations could help address these shortcomings.

Abstract PR-004: Systemic and intratumoral immune profiling in metastatic pancreatic cancer patients who received front-line FOLFIRINOX and were treated with combination immunotherapy with CTLA-4 blockade in the maintenance setting

Background: Metastatic pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis with a 5-year survival rate of 10%. For patients with metastatic PDA who respond to but cannot tolerate multi-agent chemotherapy, such as FOLFIRINOX, beyond 4-6 months, the optimal approach is unknown. Few studies have evaluated immunotherapy in the maintenance setting for PDA. Previously, a phase 2 trial in advanced PDA showed the promise of a GM-CSF-secreting allogeneic pancreatic tumor cell-based vaccine (GVAX) with CTLA-4 inhibitor, ipilimumab (IPI) [1]. Here we describe the first clinical testing of GVAX + IPI in the maintenance setting for patients with metastatic PDA who had ongoing response or stable disease after front-line FOLFIRINOX and evaluation of immune cell changes within the peripheral blood and tumor. Methods: From 40 vaccinated patients, we obtained paired peripheral blood lymphocytes (PBLs) from 20 patients and metastatic PDA biopsies from 6 of these 20 patients at baseline and week 7 (after at least two doses of GVAX + IPI). Samples were stratified into “stable” or “progressive” cohorts based on disease status on first restaging scan. To profile peripheral immune responses to treatment, we performed mass cytometry (CyTOF) analysis using a T cell-focused panel on PBLs. To profile intratumoral immune responses, biopsies containing >30% tumor cellularity were chosen for 10-plex multiplex immunohistochemistry with T cell and myeloid cell-focused panels allowing us to examine changes in immune cell subsets after GVAX + IPI. Results. GVAX + IPI led to noticeable changes in PBLs including increases in T helper and cytotoxic effector memory cells and decrease in naïve cytotoxic T cells, regardless of disease status. Among co-inhibitory markers assayed on PBLs, GVAX + IPI upregulated TIM3 and PD-1 in most helper and cytotoxic T cells, while CTLA-4 was largely maintained. Interrogation of the metastatic tumor microenvironment at baseline and on-treatment revealed significant increases in CD8+ T cells and pro-inflammatory M1 macrophages and decrease in pro-tumor M2 macrophages. Based on the CD8+ T cell functional status, there were increases in late effector (EOMES-PD-1+) and memory (EOMES-PD-1-) CD8+ T cells in the metastatic tumor after immunotherapy. Conclusions: In summary, we have proposed a mechanism for our immunotherapy in the maintenance setting. GVAX may be inducing systemic and intratumoral activation of naïve T cells to antigen-specific T cells and promoting a decrease in immunosuppressive cells in the metastatic PDA microenvironment. Meanwhile, IPI may be blocking CTLA-4, which improves priming of T cells, but also may be leading to upregulation of regulatory markers TIM3 and PD-1 on T cell subsets as a compensatory mechanism. This trial highlights the challenge to inducing effective anti-tumor immune responses in metastatic PDA with inducible counterregulatory mechanisms. These compensatory increases could provide targets for the next generation of studies. 1Le DT, et al. J Immunother. 2013

Citation Format: Annie A. Wu, Katherine M. Bever, Won Jin Ho, Elana J. Fertig, Nan Niu, Lei Zheng, Rose M. Parkinson, Jennifer N. Durham, Beth Onners, Anna K. Ferguson, Cara Wilt, Andrew H. Ko, Andrea Wang-Gillam, Daniel A. Laheru, Robert A. Anders, Elizabeth D. Thompson, Elizabeth A. Sugar, Elizabeth M. Jaffee, Dung T. Le. Systemic and intratumoral immune profiling in metastatic pancreatic cancer patients who received front-line FOLFIRINOX and were treated with combination immunotherapy with CTLA-4 blockade in the maintenance setting [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PR-004.

A Phase II Study of Allogeneic GM-CSF-Transfected Pancreatic Tumor Vaccine (GVAX) with Ipilimumab as Maintenance Treatment for Metastatic Pancreatic Cancer

PURPOSE

This phase II study tested granulocyte-macrophage colony-stimulating factor (GM-CSF)-allogeneic pancreatic tumor cells (GVAX) and ipilimumab in metastatic pancreatic ductal adenocarcinoma (PDA) in the maintenance setting.

PATIENTS AND METHODS

Patients with PDA who were treated with front-line chemotherapy consisting of 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) in the metastatic setting and had ongoing response or stable disease after 8-12 doses were eligible. Patients were randomized 1:1 to treatment with GVAX and ipilimumab given every 3 weeks for four doses then every 8 weeks (Arm A) or to FOLFIRINOX continuation (Arm B). The primary objective was to compare overall survival (OS) between the two arms.

RESULTS

Eighty-two patients were included in the final analysis (Arm A: 40; Arm B: 42). The study was stopped for futility after interim analysis. Median OS was 9.38 months [95% confidence interval (CI), 5.0-12.2] for Arm A and 14.7 months (95% CI, 11.6-20.0) for Arm B (HR, 1.75; P = 0.019). Using immune-related response criteria, two partial responses (5.7%) were observed in Arm A and four (13.8%) in Arm B. GVAX + ipilimumab promoted T-cell differentiation into effector memory phenotypes both in the periphery and in the tumor microenvironment and increased M1 macrophages in the tumor.

CONCLUSIONS

GVAX and ipilimumab maintenance therapy did not improve OS over continuation of chemotherapy and resulted in a numerically inferior survival in metastatic PDA. However, clinical responses and biological effects on immune cells were observed. Further study of novel combinations in the maintenance treatment of metastatic PDA is feasible.

An exploratory study of metformin with or without rapamycin as maintenance therapy after induction chemotherapy in patients with metastatic pancreatic adenocarcinoma

Purpose: Metformin combined with the mTOR inhibitor rapamycin showed potential synergistic anti-tumor activity in preclinical studies in pancreatic ductal adenocarcinoma (PDA). This phase 1b study (NCT02048384) was conducted to evaluate the feasibility and activity of metformin +/– rapamycin in the maintenance setting for unselected patients with metastatic PDA (mPDA) treated with chemotherapy.

Materials and Methods: Eligible patients with stable or responding mPDA after ≥ 6 months on chemotherapy were randomized 1:1 to metformin alone (Arm A) or with rapamycin (Arm B), stratified by prior treatment with FOLFIRINOX. Fluorodeoxyglucose (FDG) PET scans and peripheral blood mononuclear cells were obtained for exploratory analyses.

Results: 22 subjects (11 per arm) received treatment per protocol. Median PFS/OS were 3.5 and 13.2 months respectively, with 2 year OS rate of 37%; there were no differences between arms. No responses were observed by RECIST; however, decreases in FDG avidity and/or CA19-9 were observed in several long-term survivors. Treatment related adverse events of Grade ≥ 3 occurred in 0% vs 27% of patients in Arm A vs B and were asymptomatic hematologic or electrolyte abnormalities that were not clinically significant. Improved survival was associated with low baseline neutrophil: lymphocyte ratio, baseline lack of assessable disease by PET, and greater expansion of dendritic cells following treatment.

Conclusions: Metformin +/– rapamycin maintenance for mPDA was well-tolerated and several patients achieved stable disease associated with exceptionally long survival. Further prospective studies are needed to clarify the role of these agents in the maintenance setting and to enhance patient selection for such approaches.

An exploratory study of metformin (Met) with or without rapamycin (Rapa) as maintenance therapy after induction chemotherapy in patients (Pts) with metastatic pancreatic adenocarcinoma (PDA)

700

Background: Few studies have examined maintenance therapy in unselected pts with metastatic PDA (mPDA). mTOR signaling is central to several oncogenic pathways in PDA and also has a role in T cell differentiation and activation, and we hypothesized a role for mTOR inhibition (mTORi) in the maintenance setting. Methods: This was a randomized open-label study conducted at 2 sites. Eligible pts had mPDA with stable disease for ≥6 months on chemotherapy and ECOG PS 0/1. Pts were randomized 1:1 to Met 850mg BID alone (Arm A) or with Rapa 4mg daily (Arm B), stratified by prior FOLFIRINOX. Baseline and on-treatment PET scans and peripheral blood mononuclear cells were obtained for exploratory analyses. Results: 23 pts were randomized. Median age was 64 (range 34-77) and 82% had ECOG PS 1. 12 of 23 received prior FOLFIRINOX; 8 received >1 prior line of therapy. 22 subjects (11 per arm) were treated per protocol. Treatment related adverse events of Grade ≥3 were seen in 0% vs 27% of pts in Arm A vs B and were all asymptomatic hematologic or electrolyte abnormalities that were not clinically significant. Median PFS/OS were 3.5 (95% CI: 2.9-9.2)/13.2 mos (95% CI: 7.8 to not reached) respectively, with 2 yr OS rate of 37% (95% CI: 21-66%); there were no differences between treatment arms. As expected in the maximally debulked setting, no responses were observed by RECIST; however, decreases in FDG avidity and/or CA199 were observed in several long-term survivors. Better survival was associated with low baseline neutrophil to lymphocyte ratio, baseline lack of assessable disease by PET, and with expansion of dendritic cells following treatment. Compared to Met alone, Met + Rapa was associated with decreased mTOR activity on some immune cell subsets and decreased metabolic fitness, but this was not correlated with outcome. Conclusions: Met +/- rapa maintenance for mPDA was well-tolerated and several pts achieved stable disease associated with exceptionally long survival. Further prospective studies are needed to clarify the role of mTORi in the maintenance setting and to enhance pt selection for such approaches. Clinical trial information: NCT02048384.

Phase II study of nivolumab and relatlimab in advanced mismatch repair deficient (dMMR) cancers resistant to prior PD-(L)1 inhibition

TPS839

Background: Cancers deficient in DNA mismatch repair (dMMR) are highly immunogenic tumors exhibiting high rates of response to immune checkpoint inhibitors targeting the programmed cell death-1 (PD-1)/PD-1 ligand (PD-L1) interaction. These tumors are characterized by high levels of microsatellite instability (MSI-H) and an exceptionally high tumor mutation burden, thought to underlie responsiveness to immunotherapy, with higher predicted immunogenicity of mutation-associated neoantigens. However, primary and acquired resistance are observed and diversity in responses is not fully explained by variations in mutation burden. Other immune checkpoints may be acting in parallel with PD-1/PD-L1. In particular, lymphocyte activation gene 3 (LAG3) mediates exhaustion of activated T cells and may have a role in resistance to PD-(L)1 inhibitors (PD-(L)1i); therefore, we hypothesized that the addition of LAG3 inhibitor (relatlimab) to the PD-1i nivolumab may overcome resistance in these tumors. Methods: Patients with advanced dMMR/MSI-H cancer who have progressive disease (by RECIST 1.1) during or within 6 months of PD-(L)1i containing therapy, and after at least 12 weeks of therapy, and meet other eligibility will be enrolled. All patients will receive nivolumab 480mg + relatlimab 160mg every 4 weeks until intolerance or progression, or up to a maximum of 2 years. The primary endpoint is objective response rate. Key secondary endpoints include safety, progression free and overall survival, and other response endpoints as measured by RECIST 1.1 and iRECIST criteria. Exploratory objectives will include analysis of the tumor microenvironment on biopsies obtained at baseline and on-treatment, analysis of T cell populations in the tumor and in the periphery and functional characterization of mutation-associated neoantigen-specific T cells. Studies of the microbiome will be conducted on stool and oral wash samples. Enrollment of 21 patients is planned. Clinical trial information: NCT03607890.

Integrating Immunotherapy Into Colorectal Cancer Care

This article provides guidance on how to incorporate immunotherapy into colorectal cancer care. We review the identification of appropriate patients, available immunotherapy agents, benefits and risks of therapy, and how to overcome potential barriers to access. With recent US Food and Drug Administration approvals of two programmed death 1 (PD-1) receptor inhibitors for use in colorectal cancer, and dual therapy with combined nivolumab (PD-1) and ipilimumab (cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4] blocking antibody), it is vital that oncology providers be aware of how and when to implement these therapy options.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor-1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair-deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers' tissue of origin.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor-1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair-deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers' tissue of origin.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor-1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair-deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers' tissue of origin.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

Phase II study of GM-CSF secreting allogeneic pancreatic cancer vaccine (GVAX) with PD-1 blockade antibody and stereotactic body radiation therapy (SBRT) for locally advanced pancreas cancer (LAPC)

TPS4154

Background: Optimal treatment strategy beyond systemic chemotherapy for LAPC remains undefined. SBRT improves local control, but distant metastasis free survival (DMFS) is only 7.7 months. Checkpoint inhibitors are poor monotherapies in pancreas cancer, but may be primed by SBRT via absocopal effect and GVAX, which induces novel lymphoid infiltrates and increased effector T-cells in tumor microenvironment. Methods: This is a single-arm, single-institution, open-label study for pts with LAPC. Eligibility: surgically unresectable LAPC, predominant adenocarcinoma at diagnosis, with ECOG 0-1, who remain metastases free after 4-8 cycles of FOLFIRINOX or gemcitabine/abraxane based-chemotherapy. Exclusion: those off chemotherapy > 49 days prior to study treatment, prior immunotherapy, active immunosuppressive use, autoimmune disease, HIV, HBV, or HCV infection, and non-oncology vaccines within 28 days of study treatment. Pts receive cyclophosphamide (200mg/m2 IV) and pembrolizumab (200mg IV) on day 1, followed by GVAX (six intradermal injections) on day 2 every three weeks for two cycles, with cycle 2 initiating concurrently with five days of SBRT. If non-metastatic, pts undergo surgical resection, nano-knife, or EUS guided biopsy (if non-surgical). Pts receive two further cycles of chemotherapy, and if remain free of metastases, receive q3 week cyclophosphamide, pembrolizumab, and GVAX for six cycles, then are monitored for two years. The primary endpoint is DMFS. Secondary endpoints include overall survival, surgical resectability, pathologic response, quality of life, and toxicity. Exploratory objectives of peripheral antigen specific t-cell responses, and changes in immune parameters of tumor microenvironment. 11 of 54 pts have been enrolled since July 2016. Clinical trial information: NCT02648282.