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Purpose: Two studies in previously treated metastatic pancreatic cancer have been completed combining GVAX pancreas vaccine (GM-CSF–secreting allogeneic pancreatic tumor cells) with cyclophosphamide (Cy) and CRS-207 (live, attenuated Listeria monocytogenes–expressing mesothelin). In the current study, we compared Cy/GVAX followed by CRS-207 with (Arm A) or without nivolumab (Arm B). Patients and Methods: Patients with pancreatic adenocarcinoma who received one prior therapy for metastatic disease and RECIST measurable disease were randomized 1:1 to receive treatment on Arm A or Arm B. The primary objective was to compare overall survival (OS) between the arms. Additional objectives included assessment of progression-free survival, safety, tumor responses, CA19-9 responses, and immunologic correlates. Results: Ninety-three patients were treated (Arm A, 51; Arm B, 42). The median OS in Arms A and B were 5.9 [95% confidence interval (CI), 4.7–8.6] and 6.1 (95% CI, 3.5–7.0) months, respectively, with an HR of 0.86 (95% CI, 0.55–1.34). Objective responses were seen in 3 patients using immune-related response criteria (4%, 2/51, Arm A; 2%, 1/42, Arm B). The grade ≥3 related adverse event rate, whereas higher in Arm A (35.3% vs. 11.9%) was manageable. Changes in the microenvironment, including increase in CD8+ T cells and a decrease in CD68+ myeloid cells, were observed in long-term survivors in Arm A only. Conclusions: Although the study did not meet its primary endpoint of improvement in OS of Arm A over Arm B, the OS was comparable with standard therapy. Objective responses and immunologic changes in the tumor microenvironment were evident.

PURPOSE KEYNOTE-164 (NCT02460198) evaluated the antitumor activity of pembrolizumab in previously treated, metastatic, microsatellite instability–high/mismatch repair–deficient (MSI-H/dMMR) colorectal cancer (CRC). METHODS This phase II open-label study involved 128 centers worldwide. Eligible patients were age ≥ 18 years and had metastatic MSI-H/dMMR CRC treated with ≥ 2 prior lines of standard therapy, including fluoropyrimidine, oxaliplatin, and irinotecan with or without anti–vascular endothelial growth factor/epidermal growth factor receptor monoclonal antibody (cohort A) or ≥ 1 prior line of therapy (cohort B). MSI-H/dMMR status was assessed locally. Patients received pembrolizumab 200 mg every 3 weeks for up to 2 years until progression, unacceptable toxicity, or withdrawal. The primary end point was objective response rate by RECIST version 1.1 by independent central review. Secondary end points were duration of response, progression-free survival (PFS), overall survival, safety, and tolerability. RESULTS A total of 124 patients with MSI-H/dMMR CRC (61 in cohort A, 63 in cohort B) enrolled. At data cutoff, median follow-up was 31.3 months (range, 0.2-35.6 months) for cohort A and 24.2 months (range, 0.1-27.1 months) for cohort B. Objective response rate was 33% (95% CI, 21% to 46%) and 33% (95% CI, 22% to 46%), respectively, with median duration of response not reached in either cohort. Median PFS was 2.3 months (95% CI, 2.1 to 8.1 months) and 4.1 months (95% CI, 2.1 to 18.9 months). Median overall survival was 31.4 months (95% CI, 21.4 months to not reached) and not reached (95% CI, 19.2 months to not reached). Treatment-related grade 3-4 adverse events occurred in 10 patients (16%) in cohort A and 8 (13%) in cohort B, with the most common occurring in ≥ 2 patients being pancreatitis, fatigue, increased alanine aminotransferase, and increased lipase (2 patients each; 3%) in cohort A. CONCLUSION Pembrolizumab is effective with a manageable safety profile in patients with MSI-H/dMMR CRC.

Transforming growth factor beta (TGFβ) is a multipotent immunosuppressive cytokine. TGFβ excludes immune cells from tumors, and TGFβ inhibition improves the efficacy of cytotoxic and immune therapies. Using preclinical colorectal cancer models in cell type-conditional TGFβ receptor I (ALK5) knockout mice, we interrogate this mechanism. Tumor growth delay and radiation response are unchanged in animals with Treg or macrophage-specific ALK5 deletion. However, CD8αCre-ALK5flox/flox (ALK5ΔCD8) mice reject tumors in high proportions, dependent on CD8+ T cells. ALK5ΔCD8 mice have more tumor-infiltrating effector CD8+ T cells, with more cytotoxic capacity. ALK5-deficient CD8+ T cells exhibit increased CXCR3 expression and enhanced migration towards CXCL10. TGFβ reduces CXCR3 expression, and increases binding of Smad2 to the CXCR3 promoter. In vivo CXCR3 blockade partially abrogates the survival advantage of an ALK5ΔCD8 host. These data demonstrate a mechanism of TGFβ immunosuppression through inhibition of CXCR3 in CD8+ T cells, thereby limiting their trafficking into tumors., TGFβ has a role in cancer immunosuppression but the exact mechanisms haven’t been fully elucidated. Here, using mouse models deficient in TGFβ-signaling, the authors show that loss of ALK5 in CD8 + T cells enhances their tumour trafficking and cytotoxicity suggesting that ALK5 inhibitors may have clinical utility.

For patients with advanced hepatocellular carcinoma, sorafenib is the only approved drug worldwide, and outcomes remain poor. We aimed to assess the safety and efficacy of nivolumab, a programmed cell death protein-1 (PD-1) immune checkpoint inhibitor, in patients with advanced hepatocellular carcinoma with or without chronic viral hepatitis.We did a phase 1/2, open-label, non-comparative, dose escalation and expansion trial (CheckMate 040) of nivolumab in adults (≥18 years) with histologically confirmed advanced hepatocellular carcinoma with or without hepatitis C or B (HCV or HBV) infection. Previous sorafenib treatment was allowed. A dose-escalation phase was conducted at seven hospitals or academic centres in four countries or territories (USA, Spain, Hong Kong, and Singapore) and a dose-expansion phase was conducted at an additional 39 sites in 11 countries (Canada, UK, Germany, Italy, Japan, South Korea, Taiwan). At screening, eligible patients had Child-Pugh scores of 7 or less (Child-Pugh A or B7) for the dose-escalation phase and 6 or less (Child-Pugh A) for the dose-expansion phase, and an Eastern Cooperative Oncology Group performance status of 1 or less. Patients with HBV infection had to be receiving effective antiviral therapy (viral load100 IU/mL); antiviral therapy was not required for patients with HCV infection. We excluded patients previously treated with an agent targeting T-cell costimulation or checkpoint pathways. Patients received intravenous nivolumab 0·1-10 mg/kg every 2 weeks in the dose-escalation phase (3+3 design). Nivolumab 3 mg/kg was given every 2 weeks in the dose-expansion phase to patients in four cohorts: sorafenib untreated or intolerant without viral hepatitis, sorafenib progressor without viral hepatitis, HCV infected, and HBV infected. Primary endpoints were safety and tolerability for the escalation phase and objective response rate (Response Evaluation Criteria In Solid Tumors version 1.1) for the expansion phase. This study is registered with ClinicalTrials.gov, number NCT01658878.Between Nov 26, 2012, and Aug 8, 2016, 262 eligible patients were treated (48 patients in the dose-escalation phase and 214 in the dose-expansion phase). 202 (77%) of 262 patients have completed treatment and follow-up is ongoing. During dose escalation, nivolumab showed a manageable safety profile, including acceptable tolerability. In this phase, 46 (96%) of 48 patients discontinued treatment, 42 (88%) due to disease progression. Incidence of treatment-related adverse events did not seem to be associated with dose and no maximum tolerated dose was reached. 12 (25%) of 48 patients had grade 3/4 treatment-related adverse events. Three (6%) patients had treatment-related serious adverse events (pemphigoid, adrenal insufficiency, liver disorder). 30 (63%) of 48 patients in the dose-escalation phase died (not determined to be related to nivolumab therapy). Nivolumab 3 mg/kg was chosen for dose expansion. The objective response rate was 20% (95% CI 15-26) in patients treated with nivolumab 3 mg/kg in the dose-expansion phase and 15% (95% CI 6-28) in the dose-escalation phase.Nivolumab had a manageable safety profile and no new signals were observed in patients with advanced hepatocellular carcinoma. Durable objective responses show the potential of nivolumab for treatment of advanced hepatocellular carcinoma.Bristol-Myers Squibb.

Purpose: Limited options exist for patients with advanced pancreatic cancer progressing after 1 or more lines of therapy. A phase II study in patients with previously treated metastatic pancreatic cancer showed that combining GVAX pancreas (granulocyte-macrophage colony-stimulating factor-secreting allogeneic pancreatic tumor cells) with cyclophosphamide (Cy) and CRS-207 (live, attenuated Listeria monocytogenes expressing mesothelin) resulted in median overall survival (OS) of 6.1 months, which compares favorably with historical OS achieved with chemotherapy. In the current study, we compared Cy/GVAX + CRS-207, CRS-207 alone, and standard chemotherapy in a three-arm, randomized, controlled phase IIb trial. Patients and Methods: Patients with previously treated metastatic pancreatic adenocarcinoma were randomized 1:1:1 to receive Cy/GVAX + CRS-207 (arm A), CRS-207 (arm B), or physician's choice of single-agent chemotherapy (arm C). The primary cohort included patients who had failed ≥2 prior lines of therapy, including gemcitabine. The primary objective compared OS between arms A and C in the primary cohort. The second-line cohort included patients who had received 1 prior line of therapy. Additional objectives included OS between all treatment arms, safety, and tumor responses. Results: The study did not meet its primary efficacy endpoint. At the final study analysis, median OS [95% confidence interval (CI)] in the primary cohort (N = 213) was 3.7 (2.9–5.3), 5.4 (4.2–6.4), and 4.6 (4.2–5.7) months in arms A, B, and C, respectively, showing no significant difference between arm A and arm C [P = not significant (NS), HR = 1.17; 95% CI, 0.84–1.64]. The most frequently reported adverse events in all treatment groups were chills, pyrexia, fatigue, and nausea. No treatment-related deaths occurred. Conclusions: The combination of Cy/GVAX + CRS-207 did not improve survival over chemotherapy. (ClinicalTrials.gov ID: NCT02004262) See related commentary by Salas-Benito et al., p. 5435

BACKGROUND Reports have demonstrated the superior activity of combining both irinotecan and oxaliplatin (FOLFOXIRI) therapy. An option for gaining similar benefits with less toxicity would be the administration of irinotecan through a hepatic artery approach. The aim of this study was to assess the response and adverse event rates for irinotecan drug-eluting beads (DEBIRI) with folinic acid, 5-fluorouracil, and oxaliplatin (FOLFOX) and bevacizumab as a first-line treatment for unresectable colorectal liver metastasis. METHODS Patients with colorectal liver metastases were randomly assigned to modified FOLFOX (mFOLFOX) and bevacizumab or mFOLFOX6, bevacizumab, and DEBIRI (FOLFOX-DEBIRI). The primary endpoint was the response rate. The secondary endpoints were adverse events, the rate of conversion to resection, and progression-free survival. RESULTS The intention-to-treat population comprised 70 patients: 10 patients in the pilot and then 30 patients randomly assigned to the FOLFOX-DEBIRI arm and 30 patients randomly assigned to the FOLFOX/bevacizumab arm. The 2 groups were similar with respect to the extent of liver involvement (30% vs 30%), but a greater percentage of patients in the FOLFOX-DEBIRI arm had an Eastern Cooperative Oncology Group performance status of 1 or 2 (57% vs 31%) and extrahepatic disease (56% vs 32%, P = .02). The median numbers of chemotherapy cycles were similar (10 vs 9), and there were similar rates of grade 3/4 adverse events (54% for the FOLFOX-DEBIRI group vs 46% for the FOLFOX/bevacizumab group). The overall response rate was significantly greater in the FOLFOX-DEBIRI arm versus the FOLFOX/bevacizumab arm at 2 (78% vs 54%, P = .02), 4 (95% vs 70%, P = .03), and 6 months (76% vs 60%, P = .05). There was significantly more downsizing to resection in the FOLFOX-DEBIRI arm versus the FOLFOX/bevacizumab arm (35% vs 16%, P = .05), and there was improved median progression-free survival (15.3 vs 7.6 months). CONCLUSIONS The simultaneous administration of mFOLFOX6 (with or without bevacizumab) and DEBIRI through the hepatic artery (FOLFOX-DEBIRI) is safe and does not cause treatment delays or increase the systemic toxicity of chemotherapy. This strategy leads to improved overall response rates, improved hepatic progression-free survival, and more durable overall progression-free survival in patients downsized to resection. Cancer 2015. © 2015 American Cancer Society. Cancer 2015;121:3649–3658. © 2015 American Cancer Society.

Purpose GVAX pancreas, granulocyte-macrophage colony-stimulating factor–secreting allogeneic pancreatic tumor cells, induces T-cell immunity to cancer antigens, including mesothelin. GVAX is administered with low-dose cyclophosphamide (Cy) to inhibit regulatory T cells. CRS-207, live-attenuated Listeria monocytogenes–expressing mesothelin, induces innate and adaptive immunity. On the basis of preclinical synergy, we tested prime/boost vaccination with GVAX and CRS-207 in pancreatic adenocarcinoma. Patients and Methods Previously treated patients with metastatic pancreatic adenocarcinoma were randomly assigned at a ratio of 2:1 to two doses of Cy/GVAX followed by four doses of CRS-207 (arm A) or six doses of Cy/GVAX (arm B) every 3 weeks. Stable patients were offered additional courses. The primary end point was overall survival (OS) between arms. Secondary end points were safety and clinical response. Results A total of 90 patients were treated (arm A, n = 61; arm B, n = 29); 97% had received prior chemotherapy; 51% had received ≥ two regimens for metastatic disease. Mean number of doses (± standard deviation) administered in arms A and B were 5.5 ± 4.5 and 3.7 ± 2.2, respectively. The most frequent grade 3 to 4 related toxicities were transient fevers, lymphopenia, elevated liver enzymes, and fatigue. OS was 6.1 months in arm A versus 3.9 months in arm B (hazard ratio [HR], 0.59; P = .02). In a prespecified per-protocol analysis of patients who received at least three doses (two doses of Cy/GVAX plus one of CRS-207 or three of Cy/GVAX), OS was 9.7 versus 4.6 months (arm A v B; HR, 0.53; P = .02). Enhanced mesothelin-specific CD8 T-cell responses were associated with longer OS, regardless of treatment arm. Conclusion Heterologous prime/boost with Cy/GVAX and CRS-207 extended survival for patients with pancreatic cancer, with minimal toxicity.

Predicting responses to immunotherapy 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

OX40 is a potent costimulatory receptor that can potentiate T-cell receptor signaling on the surface of T lymphocytes, leading to their activation by a specifically recognized antigen. In particular, OX40 engagement by ligands present on dendritic cells dramatically increases the proliferation, effector function, and survival of T cells. Preclinical studies have shown that OX40 agonists increase antitumor immunity and improve tumor-free survival. In this study, we performed a phase I clinical trial using a mouse monoclonal antibody (mAb) that agonizes human OX40 signaling in patients with advanced cancer. Patients treated with one course of the anti-OX40 mAb showed an acceptable toxicity profile and regression of at least one metastatic lesion in 12 of 30 patients. Mechanistically, this treatment increased T and B cell responses to reporter antigen immunizations, led to preferential upregulation of OX40 on CD4+ FoxP3+ regulatory T cells in tumor-infiltrating lymphocytes, and increased the antitumor reactivity of T and B cells in patients with melanoma. Our findings clinically validate OX40 as a potent immune-stimulating target for treatment in patients with cancer, providing a generalizable tool to favorably influence the antitumor properties of circulating T cells, B cells, and intratumoral regulatory T cells. Cancer Res; 73(24); 7189–98. ©2013 AACR.

To determine whether 1 of 2 vaccines based on dendritic cells (DCs) and poxvectors encoding CEA (carcinoembryonic antigen) and MUC1 (PANVAC) would lengthen survival in patients with resected metastases of colorectal cancer (CRC).Recurrences after complete resections of metastatic CRC remain frequent. Immune responses to CRC are associated with fewer recurrences, suggesting a role for cancer vaccines as adjuvant therapy. Both DCs and poxvectors are potent stimulators of immune responses against cancer antigens.Patients, disease-free after CRC metastasectomy and perioperative chemotherapy (n = 74), were randomized to injections of autologous DCs modified with PANVAC (DC/PANVAC) or PANVAC with per injection GM-CSF (granulocyte-macrophage colony-stimulating factor). Endpoints were recurrence-free survival overall survival, and rate of CEA-specific immune responses. Clinical outcome was compared with that of an unvaccinated, contemporary group of patients who had undergone CRC metastasectomy, received similar perioperative therapy, and would have otherwise been eligible for the study.Recurrence-free survival at 2 years was similar (47% and 55% for DC/PANVAC and PANVAC/GM-CSF, respectively) (χ P = 0.48). At a median follow-up of 35.7 months, there were 2 of 37 deaths in the DC/PANVAC arm and 5 of 37 deaths in the PANVAC/GM-CSF arm. The rate and magnitude of T-cell responses against CEA was statistically similar between study arms. As a group, vaccinated patients had superior survival compared with the contemporary unvaccinated group.Both DC and poxvector vaccines have similar activity. Survival was longer for vaccinated patients than for a contemporary unvaccinated group, suggesting that a randomized trial of poxvector vaccinations compared with standard follow-up after metastasectomy is warranted. (NCT00103142).

Background Preclinical studies have shown synergy between radiation therapy and immunotherapy. However, in almost all preclinical models, radiation is delivered in single doses or short courses of high doses (hypofractionated radiation). By contrast in most clinical settings, radiation is delivered as standard small daily fractions of 1.8-2 Gy to achieve total doses of 50–54 Gy (fractionated radiation). We do not yet know the optimal dose and scheduling of radiation for combination with chemotherapy and immunotherapy. Methods To address this, we analyzed the effect of neoadjuvant standard fractionated and hypofractionated chemoradiation on immune cells in patients with locally advanced and borderline resectable pancreatic adenocarcinoma. Results We found that standard fractionated chemoradiation resulted in a significant and extended loss of lymphocytes that was not explained by a lack of homeostatic cytokines or response to cytokines. By contrast, treatment with hypofractionated radiation therapy avoided the loss of lymphocytes associated with conventional fractionation. Conclusion Hypofractionated neoadjuvant chemoradiation is associated with reduced systemic loss of T cells. Trial registration ClinicalTrials.gov NCT01342224, April 21, 2011; NCT01903083, July 2, 2013. Electronic supplementary material The online version of this article (doi:10.1186/s40425-016-0149-6) contains supplementary material, which is available to authorized users.

3514Background: Pembrolizumab is approved for the treatment of adult and pediatric patients (pts) with previously treated MSI-H cancer regardless of tumor type or site. This approval was based in p...

Purpose: To evaluate the clinical and immunologic outcomes of DC (dendritic cell) vaccine with interleukin (IL)-2 and IFN-α 2a in metastatic renal cell carcinoma patients. Experimental Design: Eighteen consented and eligible patients were treated. Peripheral blood monocytes were cultured ex vivo into mature DCs and loaded with autologous tumor lysate. Treatment consisted of five cycles of intranodal vaccination of DCs (1 × 107 cells/1 mL Lactated Ringer's solution), 5-day continuous i.v. infusion of IL-2 (18MiU/m2), and three s.c. injections of IFN-α 2a (6MiU) every other day. Response Evaluation Criteria in Solid Tumors criteria were used for disease assessment. Correlative immunologic end points included peripheral blood lymphocyte cell phenotype and function as well as peripheral blood anti–renal cell carcinoma antibody and cytokine levels. Results: All patients received between two and five treatment cycles. Toxicities consisted of known and expected cytokine side effects. Overall objective clinical response rate was 50% with three complete responses. Median time to progression for all patients was 8 months, and median survival has not been reached (median follow up of 37+ months). Treatment-related changes in correlative immunologic end points were noted and the level of circulating CD4+ T regulatory cells had a strong association with outcome. Pre–IP-10 serum levels approached significance for predicting outcome. Conclusions: The clinical and immunologic responses observed in this trial suggest an interaction between DC vaccination and cytokine therapy. Our data support the hypothesis that modulation of inflammatory, regulatory, and angiogenic pathways are necessary to optimize therapeutic benefit in renal cell carcinoma patients. Further exploration of this approach is warranted.

TPS486 Background: A heterologous prime-boost vaccination strategy using GVAX pancreas and CRS-207 is showing promise in patients with pancreatic adenocarcinoma (PDA) (Le, JCO 2015). Furthermore, blockade of the immune checkpoint programmed death-1 (PD-1) is active in some cancers. Combinatorial strategies aimed at priming tumor antigen-specific T cells while simultaneously blocking negative checkpoints may be necessary to improve outcomes in PDA. GVAX is composed of allogeneic pancreatic cancer cells modified to express GM-CSF and induces a broad response against multiple tumor antigens. GVAX is given with low-dose cyclophosphamide (CY) to inhibit regulatory T cells. CRS-207 is live-attenuated Listeria monocytogenes engineered to express the tumor-associated antigen mesothelin. CRS-207 boosts responses against mesothelin and is unique in its capacity to stimulate both innate and adaptive immunity by activating T cells and NK cells. Nivolumab is an antibody against PD-1. Methods: This is a phase 2 study comparing CY/GVAX and CRS-207 with or without nivolumab in subjects with PDA who failed only one chemotherapy regimen for metastatic disease. Subjects are randomized in a 1:1 ratio to receive either 2 doses of CY/nivolumab/GVAX and 4 doses of nivolumab/CRS-207 (Arm A) or 2 doses of CY/GVAX and 4 doses of CRS-207 (Arm B). The primary objective is to compare OS between Arms A and B. Secondary/exploratory objectives include: assessment of safety and clinical responses (tumor assessments and CA19-9 levels) and correlation of Lm- and mesothelin-specific T cell and other immunological responses with OS, progression-free survival and best overall response. Clinical trial information: NCT02243371.

Purpose Oxaliplatin, a platinum-type alkylator, is not classified as a vesicant but can cause local reactions when infused by peripheral vein. Providence Cancer Center, like other institutions, deferred the venous administration method to clinical judgment incorporating patient preference. Patient experience was evaluated for oxaliplatin-related local reactions by peripheral or central venous administration. Methods A retrospective review of the electronic medical record was performed of the period of January 2011 to March 2013 to identify patients who received oxaliplatin. Included were 59 patients who were given the option of either peripheral or central venous drug administration. The two patient groups (peripheral vein vs. central vein administration) were compared in terms of frequency and type of local reactions (redness/discoloration, swelling, numbness/cold, or pain/discomfort). Results Nineteen (63.3%) of the patients in the peripheral vein group experienced some type of local reaction compared to none in the central vein group ( p Conclusion This is the first published report to characterize and quantify a single institution's experience with oxaliplatin-related local reactions. A significantly greater number of local reactions, particularly pain, occurred with the administration of oxaliplatin peripherally vs. centrally. This analysis impacted our institution's best practice for oxaliplatin infusions.

Reports have demonstrated the superior activity of combining both irinotecan and oxaliplatin (FOLFOXIRI) therapy. An option for gaining similar benefits with less toxicity would be the administration of irinotecan through a hepatic artery approach. The aim of this study was to assess the response and adverse event rates for irinotecan drug-eluting beads (DEBIRI) with folinic acid, 5-fluorouracil, and oxaliplatin (FOLFOX) and bevacizumab as a first-line treatment for unresectable colorectal liver metastasis.Patients with colorectal liver metastases were randomly assigned to modified FOLFOX (mFOLFOX) and bevacizumab or mFOLFOX6, bevacizumab, and DEBIRI (FOLFOX-DEBIRI). The primary endpoint was the response rate. The secondary endpoints were adverse events, the rate of conversion to resection, and progression-free survival.The intention-to-treat population comprised 70 patients: 10 patients in the pilot and then 30 patients randomly assigned to the FOLFOX-DEBIRI arm and 30 patients randomly assigned to the FOLFOX/bevacizumab arm. The 2 groups were similar with respect to the extent of liver involvement (30% vs 30%), but a greater percentage of patients in the FOLFOX-DEBIRI arm had an Eastern Cooperative Oncology Group performance status of 1 or 2 (57% vs 31%) and extrahepatic disease (56% vs 32%, P = .02). The median numbers of chemotherapy cycles were similar (10 vs 9), and there were similar rates of grade 3/4 adverse events (54% for the FOLFOX-DEBIRI group vs 46% for the FOLFOX/bevacizumab group). The overall response rate was significantly greater in the FOLFOX-DEBIRI arm versus the FOLFOX/bevacizumab arm at 2 (78% vs 54%, P = .02), 4 (95% vs 70%, P = .03), and 6 months (76% vs 60%, P = .05). There was significantly more downsizing to resection in the FOLFOX-DEBIRI arm versus the FOLFOX/bevacizumab arm (35% vs 16%, P = .05), and there was improved median progression-free survival (15.3 vs 7.6 months).The simultaneous administration of mFOLFOX6 (with or without bevacizumab) and DEBIRI through the hepatic artery (FOLFOX-DEBIRI) is safe and does not cause treatment delays or increase the systemic toxicity of chemotherapy. This strategy leads to improved overall response rates, improved hepatic progression-free survival, and more durable overall progression-free survival in patients downsized to resection.

4013 Background: Many pts with advanced HCC progress on SOC therapy. Nivo is a fully human anti–PD-1 IgG4 mAb that demonstrated durable responses (20% ORR with a median DOR of 9.9 mo; 9-mo OS rate was 74%) in pts with advanced HCC in the dose-expansion (EXP) phase of the CheckMate 040 study (NCT01658878; Melero et al. 2017). Here we present survival and durability of response data in both sor-naive and -experienced pts with advanced HCC in CheckMate 040. Methods: Pts naive to or previously treated with sor received nivo in phase 1/2 dose-escalation (ESC; 0.1–10 mg/kg) and -EXP (3 mg/kg) cohorts Q2W regardless of PD-L1 status. Primary endpoints were safety/tolerability (ESC) and ORR (EXP; ORR by investigator [INV] and blinded independent central review [BICR]) using RECIST v1.1. Secondary endpoints included DOR, DCR, and OS. Biomarkers were assessed using pre-treatment tumor samples. Results: Overall, pts (N=262) had a median follow-up of 12.9 mo, and 98% had Child-Pugh scores 5–6. In sor-naive pts (n=80), the ORR (INV) was 23%, with 44% of responses (8/18) ongoing (Table). The DCR was 63%; 40% of pts had stable disease ≥6 mo. In sor-experienced pts (n=182; 91% progressed on sor), the ORRs (INV) were 16%–19%. Overall, responses occurred regardless of etiology or tumor cell PD-L1 expression. Nivo had a manageable safety profile consistent with that reported in other tumor types. Updated data with additional 4 mo of follow-up will be presented. Conclusions: Nivo demonstrated durable responses with long-term survival and favorable safety in both sor-naive and -experienced pts with advanced HCC. Clinical trial information: NCT01658878. [Table: see text]

226 Background: HCC diagnosed at advanced stages has a poor prognosis. Patients who progress on sorafenib have few options. Nivolumab, a fully human IgG4 monoclonal antibody inhibitor of programmed death-1 (PD-1), has demonstrated clinical and survival benefit in a number of tumor types. Here we report updated interim analyses of safety, efficacy, and exploratory biomarkers in patients with advanced HCC treated with nivolumab in the CheckMate 040 study (NCT01658878). Methods: Patients enrolled had advanced HCC with or without hepatitis C or B virus (HCV or HBV) infection. Prior sorafenib was allowed. Phase 1 dose-escalation evaluated nivolumab (0.1–10 mg/kg) Q2W. Phase 2 dose-expansion was initiated in 4 cohorts: sorafenib naïve/intolerant, sorafenib progressors, HCV infected, and HBV infected. All cohorts received nivolumab 3 mg/kg Q2W. The primary endpoint in the dose-escalation phase was safety/tolerability, and the primary endpoint in the dose-expansion phase was objective response rate (ORR) by RECIST v1.1 (central review). Secondary endpoints included duration of response (DOR), disease control rate (DCR), and overall survival (OS). Biomarkers within pre-treatment tumors were assessed. Results: Across dose escalation and expansion phases, 262 patients have been treated. Grade 3/4 treatment-related adverse events occurred in 20%. No maximum tolerated dose was reached during dose escalation (n = 48). The ORR (investigator-assessed) was 20% (95% CI 15–26) in 214 patients treated in the dose expansion phase with a median DoR of 9.9 months; DCR was 64% (95% CI 58–71). Responses were observed across etiologies and regardless of tumor PD-L1 expression. ORRs of 23% (95% CI 13–36) and 21% (95% CI 11–34) were observed in the uninfected sorafenib-naive and -treated patients, respectively. The 9-month overall survival rate in the expansion phase was 74% (95% CI 67–79). Association between immune-cell biomarkers and clinical outcomes will be presented. Conclusions: In this heavily pretreated population, responses to nivolumab were durable with encouraging overall survival. Safety was manageable and consistent with that observed in other solid tumors with no new safety signals. Clinical trial information: NCT01658878.

Overexpression of vascular endothelial growth factor in renal cell carcinoma (RCC) leads to angiogenesis, tumor progression, and inhibition of immune function. We conducted the first phase II study to estimate the efficacy and safety of bevacizumab with high-dose interleukin-2 (IL-2) therapy in patients with metastatic RCC. Eligible patients had predominantly clear cell metastatic RCC, measurable disease, a Karnofsky Performance Status of ≥80%, and adequate end-organ function. IL-2 (600,000 IU/kg) was infused intravenously every 8 hours (maximum 28 doses) during two 5-day cycles on days 1 and 15 of each 84-day course. Bevacizumab (10 mg/kg) was infused intravenously every 2 weeks beginning 2 weeks before initiating IL-2. Fifty of 51 eligible patients from 8 centers were enrolled. Median progression-free survival (PFS) was 11.2 months (90% confidence interval, 5.7-17.7), and 2-year PFS was 18% (90% confidence interval, 8%-27%). Responses included 4 complete (8%) and 11 partial (22%) responses. Toxicities did not exceed those expected from each agent alone. Combining IL-2 plus bevacizumab is feasible, with a response rate and PFS at least as high as reported previously for the single agents. The regimen did not appear to enhance the rate of durable major responses over that of IL-2 alone.

103Background: Mismatch repair deficient (dMMR) colon cancers are densely infiltrated with CD8+T cells and regress when treated with anti-programmed death-1 (PD-1) antibodies. This anti-tumor response is thought to be potentiated by the thousands of somatic mutations that when expressed as proteins result in hundreds of potentially immunogenic neo-antigens that can be recognized by the patient’s immune system. Methods: We previously reported a phase 2 study to evaluate the activity of pembrolizumab (pembro), a PD-1 antibody in treatment refractory dMMR colon cancers (NEJM 2015). We are reporting the expanded trial and updated data for the mismatch repair deficient CRC (dMMR, cohort A) and mismatch repair proficient CRC (pMMR, cohort B) cohorts. Pembro was administered at 10 mg/kg every 14 days in patients with 2 or more prior therapies. The co-primary endpoints were response and progression-free survival rate at 20 weeks. Secondary endpoints included disease control rate (DCR = CR + PR + SD), progression ...

4012Background: For pts with advanced HCC on sorafenib (sor), overall survival (OS) is 11 mo; median OS with best supportive care (BSC) post-sor failure is 7–8 mo.Safety and preliminary antitumor e...

TPS3628Background: Colorectal (CRC) cancer is the fourth most commonly diagnosed cancer in the U.S. and the second most common cause of cancer related deaths. Recent advances in immunotherapy for m...

3003Background: Mismatch repair deficiency (MRD) is feature of many cancers at a frequency of approximately 1 in 30 patients independent of tumor histology. Tumors with MRD are deficient in the repair of specific DNA replication errors and as a result accumulate hundreds to thousands of mutations per tumor genome. The high number of somatic mutations increase the chances for at least one of these mutations to result in a highly immunogenic neo-antigenic protein that can trigger a potent anti-tumor immune response in the presence of PD-1 blockade. Methods: To further test this hypothesis, we conducted a phase 2 study to evaluate the activity of pembrolizumab (pembro), a programmed death-1 (PD-1) antibody in MRD tumors independent of tumor histology using a basket design. Pembro was administered at 10 mg/kg every 14 days in patients with > 1 prior therapy. The co-primary endpoints were response and progression-free survival rate at 20 weeks. Secondary endpoints included disease control rate (DCR = CR+PR+SD)...

4078Background: HCC tumors are associated with chronic inflammation that can promote an immunosuppressive environment; anti-PD-1 therapy may counter this inhibition. Nivo, a fully human IgG4 monocl...

195 Background: Mismatch repair (MMR) deficient tumors harbor hundreds to thousands of mutations that may produce neoantigens that can be recognized and targeted by T cells. We have shown that MMR deficiency can serve as a predictive biomarker for selection of tumors across tumor histologies that may respond to programmed death-1 (PD-1) blockade. MMR deficiency is present in 15% of colorectal (CRC) however is also detected in 2-20% of gastric, small bowel, and hepatobiliary cancers. Methods: We conducted a phase II study to evaluate anti-PD-1, pembrolizumab, in patients with previously-treated, progressive, advanced cancer. Twenty-one patients with MMR deficient tumors were enrolled onto the non-CRC cohort with an additional 50 patient expansion underway. The pembrolizumab dose is 10mg/kg intravenously every 2 weeks. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) will be reported in at least the first 17 patients with non-CRC gastrointestinal (GI) cancers. Results: As of September 18, 2015, 17 patients with non-CRC GI cancers have been enrolled on the protocol with additional patients identified. The diseases represented are ampullary (N=4), pancreas (N=4), biliary (N=3), small bowel (N=3), and gastric (N=3) cancers. For the 10 evaluable patients at the time of abstract admission, ORR is 50 % (N=5/10), disease control rate is 70% (N=7/10), OS is 21 months and the median duration of response (range 5.5-17+ months) and PFS have not been reached. The median follow up duration is 7.6 months. Conclusions: PD-1 blockade shows promising activity in mismatch repair deficient GI cancers. Clinical trial information: NCT01876511.

Hepatocellular carcinoma arises in an environment of chronic injury, and wound-healing responses may vary by treatment.Peripheral blood myeloid populations were quantified in 39 patients with hepatocellular carcinoma treated with surgical or endoluminal therapy. Macrophages were quantified in tissue when available.There was a similar expansion of myeloid populations after operative procedures compared with endoluminal treatments. Immunostaining for CD68 revealed no significant differences in the number of macrophages within benign versus malignant tumors and when tumors were compared with nontumor liver. Cytotoxic CD8+ T cells were rare within tumors compared with the surrounding liver (P.0001). Progression-free survival was reduced in patients with preoperative peripheral blood monocyte expansion (P.05).These data provide preliminary evidence of poor prognostic significance of elevated peripheral blood monocyte counts. We propose that the inflammatory environment of hepatocellular carcinoma may represent a consistent feature to both predict and alter the course of disease.

Purpose Recovery of lymphocyte populations after lymphocyte depletion is implicated in therapeutic immune pathways in animal models and in patients with cancer. We sought to evaluate the effects of chemotherapy-induced lymphodepletion followed by granulocyte-macrophage colony-stimulating factor (GM-CSF) and high-dose interleukin-2 (IL-2) therapy on clinical response and the recovery of lymphocyte subcompartments in patients with metastatic melanoma. Patients and Methods This was a two-stage phase II trial design. Patients with measurable metastatic melanoma were treated with intravenous cyclophosphamide (60 mg/kg, days 1 and 2) and fludarabine (25 mg/m2, day 3 through 7) followed by two 5-day courses of intravenous high-dose bolus IL-2 (600,000 U/kg; days 8 through 12 and 21 through 25). GM-CSF (250 μg/m2/d beginning day 8) was given until granulocyte recovery. Lymphocyte recovery profiles were determined by flow cytometric phenotyping at regular intervals, and clinical outcome was assessed by Response Evaluation Criteria in Solid Tumors (RECIST). Results The trial was stopped at the end of stage 1 with four of 18 objective responses noted. Twelve patients had detailed lymphocyte subcompartments evaluated. After lymphodepletion, we observed an induction of regulatory cells (CD4+ T regulatory cells; CD8+ T suppressor cells) and of T memory cells (CD8+ T central memory cells; T effector memory RA+ cells). Expansion of circulating melanoma-specific CD8+ cells was observed in one of four HLA-A2-positive patients. Conclusion Chemotherapy-induced lymphodepletion modulates the homeostatic repopulation of the lymphocyte compartment and influences recovering lymphocyte subpopulations. Clinical activity seems similar to standard high-dose aldesleukin alone.

PurposeTo review the evidence about the efficacy and utility of radiofrequency ablation (RFA) for hepatic metastases from colorectal cancer (CRHM).MethodsThe American Society of Clinical Oncology (ASCO) convened a panel to conduct and analyze a comprehensive systematic review of the RFA literature from Medline and the Cochrane Collaboration Library.ResultsBecause data were considered insufficient to form the basis of a practice guideline, ASCO has instead published a clinical evidence review. The evidence is from single-arm, retrospective, and prospective trials. No randomized controlled trials have been included. The following three clinical issues were considered by the panel: the efficacy of surgical hepatic resection versus RFA for resectable tumors; the utility of RFA for unresectable tumors; and RFA approaches (open, laparoscopic, or percutaneous). Evidence suggests that hepatic resection improves overall survival (OS), particularly for patients with resectable tumors without extrahepatic disease. Careful patient and tumor selection is discussed at length in the literature. RFA investigators report a wide variability in the 5-year survival rate (14% to 55%) and local tumor recurrence rate (3.6% to 60%). The reported mortality rate was low (0% to 2%), and the major complications rate was commonly reported to be between 6% and 9%. RFA is currently performed with all three approaches.ConclusionThere is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as OS for patients with CRHM. Clinical trials have established that hepatic resection can improve OS for patients with resectable CRHM.

Since multiple lines of experimental and clinical data clearly identified regulatory T cells as an integral part of the immune response, these cells have become a major focus of investigation in tumor immunology. Regulatory T cells are in place to dampen ongoing immune responses and to prevent autoimmunity, but they also have profound effects in blocking therapeutic anti-tumor activity. Therefore regulatory T cells are seen as a major hurdle that must be overcome in order for cancer immunotherapy to reach its therapeutic potential. Regulatory T cells are heterogeneous with sub-populations that exhibit distinct functional features. Here we will review the individual sub-populations in regards to their mode of action and their potential impact on blocking anti-tumor immunity. Approaches to measure function and frequency of regulatory T cells in model systems and clinical trails will be discussed. Finally, we will describe possible ways to interfere with regulatory T cell-mediated immune suppression with the focus on recent pre-clinical and clinical findings.

In patients with progressive malignancy, the natural balance between proinflammatory (Yang) and inhibitory (regulatory or Yin) immune pathways is disrupted and favors cancer-specific immune suppression. Therapy with interleukin 2 (IL-2) can mobilize immune effector cells that recognize and destroy cancer. High-dose IL-2 is the only therapy that has consistently induced complete durable remissions in patients with metastatic renal cell carcinoma (RCC) but only in a few of them. The lack of benefit in most metastatic RCC patients is likely due to the ineffective manipulation of other immune circuits critical in regulating tumor cytotoxic pathways. The limited clinical activity of IL-2, RCC vaccines, and other immune therapies to date leads us to postulate that effective clinical treatment strategies will need to simultaneously enhance proinflammatory pathways and disrupt regulatory pathways. We present preliminary studies in RCC patients to highlight the complexity of the regulatory pathways and our approach to shifting the balance of proinflammatory and regulatory immune pathways using dendritic cell–tumor lysate vaccine followed by cytokine therapy.

9633 Background: Considerable evidence demonstrates the benefits of exercise for cancer survivors, but few studies focus on those living with advanced disease. We conducted a randomized trial of a ...

LBA100 Background: Somatic mutations have the potential to be recognized as “non-self” immunogenic antigens. Tumors with genetic defects in mismatch repair (MMR) harbor many more mutations than tumors of the same type without such repair defects. We hypothesized that tumors with mismatch repair defects would therefore be particularly susceptible to immune checkpoint blockade. Methods: We conducted a phase II study to evaluate the clinical activity of anti-PD-1, pembrolizumab, in 41 patients with previously-treated, progressive metastatic disease with and without MMR-deficiency. Pembrolizumab was administered at 10 mg/kg intravenously every 14 days to three cohorts of patients: those with MMR-deficient colorectal cancers (CRCs) (N = 11); those with MMR-proficient CRCs (N = 21), and those with MMR-deficient cancers of types other than colorectal (N = 9). The co-primary endpoints were immune-related objective response rate (irORR) and immune-related progression-free survival (irPFS) at 20 weeks. Results: The study met its primary endpoints for both MMR-deficient cohorts. The irORR and irPFS at 20 weeks for MMR-deficient CRC were 40% and 78%, respectively, and for MMR-deficient other cancers were 71% and 67%, respectively. In MMR-proficient CRC, irORR and irPFS at 20 weeks were 0% and 11%, respectively. Response rates and Disease Control Rates (CR+PR+SD) by RECIST criteria were 40% and 90% in MMR-deficient CRC, 0% and 11% in MMR-proficient CRC, and 71% and 71% in MMR-deficient other cancers, respectively. Median PFS and overall survival (OS) were not reached in the MMR-deficient CRC group but was 2.2 and 5.0 months in the MMR-proficient CRC cohort (HR for PFS = 0.103; 95% CI, 0.029 to 0.373; p < 0.001 and HR for OS = 0.216; 95% CI, 0.047 to 1.000; p = 0.05). Whole exome sequencing revealed an average of 1,782 somatic mutations per tumor in MMR-deficient compared to 73 in MMR-proficient tumors (p = 0.0015), and high total somatic mutation loads were associated with PFS (p = 0.02). Conclusions: MMR status predicts clinical benefit of immune checkpoint blockade with pembrolizumab. Clinical trial information: NCT01876511.

TPS489 Background: A prime-boost vaccination strategy using GVAX pancreas vaccine and CRS-207 is showing activity in patients with metastatic pancreatic adenocarcinoma (PDA). GVAX is composed of lethally-irradiated, allogeneic pancreatic cancer cells modified to express GM-CSF. GVAX induces a response against multiple tumor antigens and is given after low-dose cyclophosphamide (CY) to inhibit regulatory T cells. CRS-207 is live-attenuated Listeria monocytogenes engineered to express the tumor-associated antigen mesothelin. CRS-207 boosts responses against mesothelin and stimulates both innate and adaptive immunity by activating T cells and NK cells. Results from a phase 2 study demonstrated CY/GVAX plus CRS-207 improved overall survival (OS) compared to CY/GVAX alone (p-value

Classic T lymphocyte cytotoxicity is mediated through the T cell receptor (TCR). Defects in TCR signal transduction and cytolytic activity have been reported in tumor infiltrating T lymphocytes. We hypothesized that impaired cytotoxicity occurs in peripheral blood T cells from renal cell carcinoma (RCC) that can be reversed by exposure to rhIL-2. Peripheral blood mononuclear cells (PBMC) from 29 RCC patients and 29 healthy volunteers were isolated and cultured in the absence or presence of 10 IU/ml rhIL-2. A redirected cytotoxicity assay that requires TCR signal transduction was used with chromium-labeled P815 target cells, effector PBMC and anti-CD3 antibody. Target cell lysis was measured in “lytic units” (LU). Mean LU from RCC patients was lower than that of healthy volunteers (105.8 LU vs. 194.6 LU, P = 0.025). Exposure to rhIL-2 increased T cell-mediated lysis in both groups. Disruption of T cell cytotoxicity in RCC patients can be overcome by exposure to rhIL-2.

Meeting abstracts Recent studies have reported that decreased T cell infiltrate alone, or co-ordinate with increased macrophage infiltrate, correlate with decreased survival in a range of cancers, including patients with pancreatic cancer. Importantly, in mouse models of pancreatic cancer

174 Background: Reports have demonstrated the activity of combining both Irinotecan and Oxaliplatin into a FOLFOXIRI therapy. An option to gain similar benefits and less toxicity to FOLFOXIRI would be to administer the irinotecan through an hepatic arterial apporach. The aim of this study was to assess the maximal response and adverse event rates of Irinotecan Drug Eluting Beads (DEBIRI) with FOLFOX and Bevacizumab (Bev) as a first line treatment for unresectable colorectal liver metastasis (CLMs). Methods: Metachronous and Synchronous CLMs were randomly assigned to mFOLFOX6/Bev or mFOLFOX6, Bev and DEBIRI (FOLFOXDEBIRI). Primary end point was optimal response rates and adverse events. Secondary endpoints were patients (pts) converted to resection and survival. Results: The intention-to-treat population comprised 70 pts, 40 pts randomly assigned to the FOLFOXDEBIRI arm and 30 pts to FOLFOX/Bev arm. Both were similar with synchronous disease (50% vs. 36%), extent liver involvement (35% vs. 31%), but greater percentage in the FOLFOXDEBIRI arm of ECOG 1/2 (57% vs. 31%), p=0.04) and extra-hepatic disease (51% vs. 36%, p=0.02). Median number of chemotherapy cycles was similar in both arms of 8, with a similar Grade 3/4 adverse event rate of 54% FOLFOXDEBIRI and 46% FOLFOX/Bev arm. The overall response rate was significantly greater in the FOLFOXDEBIRI arm vs. FOLFOX/BEV at 2 mons (78% vs. 54%), 4 mons (95% vs. 70%) and 6 mons (76% vs. 60%, p=0.03). Significantly greater downsizing to resection in the FOLFOXDEBIRI arm vs. FOLFOX/Bev (35% vs. 16%, p=0.05), with an improved median progression free survival (15.3 mons vs. 7.6 mons). Overall improvement in hepatic specific progression free survival was seen in the treatment arm (12.8 mons vs. 10.5 mons). Conclusions: Simultaneous mFOLFOX6 with bevacizumab and hepatic arterial irinotecan drug eluting beads is safe, without causing chemotherapy delivery delays and without increasing chemotherapy toxicity. Simultaneous FOLFOXDEBIRI leads to improved overall response rates, improved hepatic progression free survival, and more durable overall progression free survival in patients downsized to resection. Clinical trial information: NCT00932438.