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

Long-term survival benefit of upfront chemotherapy in patients with newly diagnosed borderline resectable pancreatic cancer

The use of neoadjuvant chemotherapy or radiation for borderline resectable pancreatic adenocarcinoma (BL-PDAC) is increasing. However, the impact of neoadjuvant chemotherapy and radiation therapy on the outcome of BL-PDAC remains to be elucidated. We performed a retrospective analysis of 93 consecutive patients who were diagnosed with BL-PDAC and primarily followed at Johns Hopkins Hospital between February 2007 and December 2012. Among 93 patients, 62% received upfront neoadjuvant chemotherapy followed by chemoradiation, whereas 20% received neoadjuvant chemoradiation alone and 15% neoadjuvant chemotherapy alone. Resectability following all neoadjuvant therapy was 44%. Patients who underwent resection with a curative intent had a median overall survival (mOS) of 25.8 months, whereas those who did not undergo surgery had a mOS of 11.9 months. However, resectability and overall survival were not significantly different between the three types of neoadjuvant therapy. Nevertheless, 22% (95% CI, 0.13-0.36) of the 58 patients who received upfront chemotherapy followed by chemoradiation remained alive for a minimum of 48 months compared to none of the 19 patients who received upfront chemoradiation. Among patients who underwent curative surgical resection, 32% (95% CI, 0.19-0.55) of those who received upfront chemotherapy remained disease free at least 48 months following surgical resection, whereas none of the eight patients who received upfront chemoradiation remained disease free beyond 24 months following surgical resection. Neoadjuvant therapy with upfront chemotherapy may result in long-term survival in a subpopulation of patients with BL-PDAC.

A rare case of esophageal metastasis from pancreatic ductal adenocarcinoma: a case report and literature review

Purpose

We report a very unique case of an esophageal metastasis from a pancreatic ductal adenocarcinoma (PDAC) primary.

Methods

After obtaining consent from the patient, all relevant records of the case were obtained and retrospectively reviewed.

Results

At presentation, the patient was diagnosed with synchronous pancreatic and esophageal cancer. He received six months of neoadjuvant therapy including FOLFIRINOX (5-fluorouracil, leucovorin, irinotecan, and oxaliplatin) and stereotactic body radiation therapy (SBRT) to the pancreatic tumor followed by a combined pancreaticoduodenectomy and Ivor Lewis esophagectomy. Review of the final esophageal specimen revealed normal overlying squamous mucosa with an underlying focus of metastatic PDAC. The patient remains alive with no evidence of disease 17 months from surgery and 25 months from diagnosis.

Conclusions

Differentiating an esophageal metastasis from a PDAC primary versus a synchronous esophageal carcinoma is very difficult despite state-of-the-art diagnostic techniques performed at a high-volume tertiary cancer center. Extensive evaluation and continued follow-up of PDAC patients presenting with a synchronous esophageal lesion in a multidisciplinary setting may help ensure efficient and accurate management. In our case, neoadjuvant FOLFIRINOX and SBRT to the primary PDAC tumor followed by surgery has been an effective approach for this patient.

Inflammatory Arthritis: A Newly Recognized Adverse Event of Immune Checkpoint Blockade

This commentary summarizes current knowledge on the clinical presentation, management, and outcomes of the inflammatory arthritis which may occur as an immune‐related adverse evet of immune checkpoint inhibitor therapy. Herein, we propose a new algorithm aimed at assisting oncologists in the diagnosis and management of this immune‐related adverse event.

Association of Autoimmune Encephalitis With Combined Immune Checkpoint Inhibitor Treatment for Metastatic Cancer

IMPORTANCE

Paraneoplastic encephalitides usually precede a diagnosis of cancer and are often refractory to immunosuppressive therapy. Conversely, autoimmune encephalitides are reversible conditions that can occur in the presence or absence of cancer.

OBJECTIVE

To report the induction of autoimmune encephalitis in 2 patients after treatment of metastatic cancer with a combination of the immune checkpoint inhibitors nivolumab and ipilimumab.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective case study was conducted of the clinical and management course of 2 patients with progressive, treatment-refractory metastatic cancer who were treated with a single dose each (concomitantly) of the immune checkpoint inhibitors nivolumab, 1 mg/kg, and ipilimumab, 3 mg/kg.

EXPOSURES

Nivolumab and ipilimumab.

MAIN OUTCOMES AND MEASURES

The clinical response to immunosuppressive therapy in suspected autoimmune encephalitis in the setting of immune checkpoint inhibitor use.

RESULTS

Autoantibody testing confirmed identification of anti-N-methyl-D-aspartate receptor antibodies in the cerebrospinal fluid of 1 patient. Withdrawal of immune checkpoint inhibitors and initiation of immunosuppressive therapy, consisting of intravenous methylprednisolone sodium succinate equivalent to 1000 mg of methylprednisolone for 5 days, 0.4 mg/kg/d of intravenous immunoglobulin for 5 days, and 2 doses of rituximab, 1000 mg, in 1 patient and oral prednisone, 60 mg/d, in the other patient, resulted in improved neurologic symptoms.

CONCLUSIONS AND RELEVANCE

Immune checkpoint inhibition may favor the development of immune responses against neuronal antigens, leading to autoimmune encephalitis. Early recognition and treatment of autoimmune encephalitis in patients receiving immune checkpoint blockade therapy will likely be essential for maximizing clinical recovery and minimizing the effect of drug-related toxic effects. The mechanisms by which immune checkpoint inhibition may contribute to autoimmune encephalitis require further study.

Pembrolizumab therapy for microsatellite instability high (MSI-H) colorectal cancer (CRC) and non-CRC

3071

Background: Mismatch repair deficient cancers harbor high levels of microsatellite instability and somatic mutations. Treatment with anti-PD-1 antibodies has resulted in durable objective responses in MSI-H cancer. As part of the ongoing, global, multicenter phase 2 studies KEYNOTE(KN)164 and KN158, we assessed the efficacy of pembrolizumab in patients (pts) with MSI-H tumors. Methods: Both studies enrolled pts with MSI-H status determined locally by IHC or PCR. KN164 enrolled pts with MSI-H CRC and ≥2 prior therapies, whereas the multicohortKN158 study included pts with MSI-H non-CRC and ≥1 prior therapy. Eligible pts in both studies received pembrolizumab 200 mg Q3W until progression, unacceptable toxicity, or pt/investigator decision. Tumor response was assessed every 9 wk by independent review per RECIST v1.1. Primary endpoint was ORR. Secondary endpoints included DOR, PFS, OS, and safety. Analyses were performed in pts from KN164 and KN158 who had ≥27 wk of follow-up as of Aug 3, 2016 and Oct 19, 2016, respectively. Results: KN164 enrolled 61 pts with MSI-H CRC (90% with ≥2 prior therapies) whereas KN158 included 21 pts with MSI-H non-CRC (42% with ≥2 prior therapies). In KN158 the most common tumor types were endometrial and small intestinal cancer (n = 4 each), cholangiocarcinoma (n = 3), and gastric and pancreatic cancer (n = 2 each). Median follow-up was 7.4 mo for MSI-H CRC and 4.5 mo for MSI-H non-CRC. ORR for MSI-H CRC was 26.2% (95% CI, 15.8%-39.1%), with 15 confirmed responses and 1 unconfirmed response, and ORR for MSI-H non-CRC was 42.9% (21.8%-66.0%), with 8 confirmed responses and 1 unconfirmed response. DCR was 50.8% (n = 31; 37.7%-63.9%) for MSI-H CRC and 66.7% (n = 14; 38.4%-83.7%) for MSI-H non-CRC. Median duration of response was not reached for either MSI-H CRC or non-CRC, and 100% of responses were ongoing. Survival and safety analyses are ongoing. Conclusions: Early results from KN164 and KN158 confirm the robust antitumor activity of pembrolizumab in heavily pretreated pts with MSI-H cancers. Clinical trial information: NCT02628067; NCT02460198.

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.

Nivolumab ± ipilimumab in pts with advanced (adv)/metastatic chemotherapy-refractory (CTx-R) gastric (G), esophageal (E), or gastroesophageal junction (GEJ) cancer: CheckMate 032 study

4014

Background: In the phase 3 ONO-12 study, 3rd- or later-line nivolumab (N) monotherapy prolonged OS vs placebo in Asian pts with adv G/GEJ cancer (median OS, 5.3 vs 4.1 mo; HR, 0.63; P < 0.0001; ASCO-GI 2017, Kang YK et al. J Clin Oncol. 2017;35 (suppl 4S) [abstract 2]). The phase 1/2 CheckMate 032 study showed favorable clinical activity of N ± ipilimumab (I) in Western pts with adv CTx-R G/E/GEJ cancer (NCT01928394). We report updated long-term follow-up data of G/E/GEJ pts in CheckMate 032. Methods: Pts received N 3 mg/kg Q2W (N3), N 1 mg/kg + I 3 mg/kg Q3W (N1+I3), or N 3 mg/kg + I 1 mg/kg Q3W (N3+I1). Primary endpoint was ORR. Secondary endpoints included DOR, OS, PFS, and safety. Efficacy in pts by PD-L1 status was assessed. Results: 160 heavily pretreated pts (79% had ≥ 2 prior Tx) were enrolled (N3, n = 59; N1+I3, n = 49; N3+I1, n = 52); 24% had PD-L1+ (≥ 1%) tumors. ORR was 12% in N3, 24% in N1+I3, and 8% in N3+I1. In pts with PD-L1 ≥ 1%, ORR was 19% (3/16) in N3, 40% (4/10) in N1+I3, and 23% (3/13) in N3+I1; in pts with PD-L1 < 1%, ORR was 12% (3/26), 22% (7/32), and 0% (0/30), respectively. Median DOR was 7.1 mo in N3, 7.9 mo in N1+I3, and NA in N3+I1. OS in all pts and in pts with PD-L1 ≥ 1% is in the Table. Grade 3–4 treatment-related AEs reported in ≥ 10% of pts in any treatment arm were diarrhea (N3, 2%; N1+I3, 14%; N3+I1, 2%), ALT increased (N3, 3%; N1+I3, 14%; N3+I1, 4%), and AST increased (N3, 5%; N1+I3, 10%; N3+I1, 2%). Conclusions: N ± I led to durable responses and long-term OS in heavily pretreated Western pts with adv G/E/GEJ cancer, which is consistent with the clinical activity observed in Asian pts in the ONO-12 study. Safety was consistent with prior reports. These data support ongoing investigation of N ± I in pts with adv G/E/GEJ cancer. Clinical trial information: NCT01928394. [Table: see text]

Phase 3, open-label, randomized study of first-line pembrolizumab (pembro) vs investigator-choice chemotherapy for mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) metastatic colorectal carcinoma (mCRC): KEYNOTE-177

TPS3618

Background: About 5% of mCRCs are dMMR, leading to high levels of MSI. CRCs with MSI-H have abundant lymphocyte infiltrates and strong expression of immune checkpoints. In the phase 2 KEYNOTE-016 study, the anti-programmed death 1 (PD-1) antibody pembro provided an ORR of 40% in patients (pts) with progressive dMMR mCRC vs 0% in pts with MMR-proficient mCRC. KEYNOTE-177 (ClinicalTrials.gov, NCT02563002) is an international, randomized, open-label, phase 3 study designed to evaluate the efficacy and safety of pembro vs standard-of-care (SOC) chemotherapy in the first-line setting for dMMR or MSI-H mCRC. Methods: Key eligibility criteria include age ≥ 18 years, locally confirmed dMMR or MSI-H stage IV CRC, measurable disease per RECIST v1.1 by local site assessment, ECOG performance status 0-1, no active autoimmune disease or brain metastases, and no prior therapy for mCRC. Pts are to be randomized 1:1 to receive either pembro 200 mg Q3W or investigator’s choice of SOC chemotherapy, which must be chosen prior to randomization; options include mFOLFOX6 or FOLFIRI alone or in combination with bevacizumab or cetuximab. Treatment is to continue until disease progression, unacceptable toxicity, pt/investigator decision, or completion of 35 cycles (pembro only). Response is to be evaluated Q9W per RECIST v1.1 by central imaging vendor review and per RECIST adapted for immunotherapy response patterns. Pts in the SOC arm who have disease progression and meet crossover criteria may be eligible to receive pembro for up to 17 treatment cycles. Eligible pts may continue pembro beyond initial RECIST-defined progression. AEs are to be assessed throughout treatment and for 30 days thereafter (90 days for serious AEs) and graded per NCI CTCAE v4.0. Pts are to be followed for survival Q9W. Primary end point is PFS per RECIST v1.1 by central imaging vendor review. Secondary end points include ORR per RECIST v1.1 by central imaging vendor review, OS, and safety and tolerability. Other end points include DOR and HRQoL. Planned enrollment in KEYNOTE-177 is 270 pts across 21 countries. Clinical trial information: NCT02563002.

KEYNOTE-177: Randomized phase III study of pembrolizumab versus investigator-choice chemotherapy for mismatch repair-deficient or microsatellite instability-high metastatic colorectal carcinoma

TPS815

Background: A subset of colorectal carcinomas (CRCs) are characterized by mismatch repair (MMR) deficiency resulting in microsatellite instability (MSI). MSI-high tumors contain high levels of lymphocyte infiltrates and express the PD-1 immune checkpoint receptor and its ligand, PD-L1. In the phase 2 KEYNOTE-016 study, the anti–PD-1 antibody pembrolizumab demonstrated antitumor activity against MMR-deficient tumors in patients with treatment-refractory metastatic CRC. KEYNOTE-177 (ClinicalTrials.gov, NCT02563002) is an international, randomized, open-label, phase 3 study of pembrolizumab versus standard-of-care (SOC) chemotherapy in first-line MMR-deficient or MSI-high metastatic CRC. Methods: Key eligibility criteria include age ≥18 years, confirmed MSI-high or MMR-deficient metastatic CRC, ECOG PS 0-1, no active autoimmune disease or brain metastases, and no prior therapy for metastatic disease. ~270 patients will be randomly assigned 1:1 to receive either pembrolizumab 200 mg every 3 weeks or investigator's choice of SOC chemotherapy (mFOLFOX6 or FOLFIRI alone or in combination with bevacizumab or cetuximab, chosen before randomization). Treatment is to continue until progressive disease (PD), unacceptable toxicity, patient/investigator decision, or completion of 35 cycles (pembrolizumab only). Response is to be assessed every 9 weeks per RECIST v1.1 by central imaging vendor review and per RECIST adapted for immunotherapy response patterns. Eligible patients may continue pembrolizumab beyond initial RECIST-defined progression. Patients in the SOC arm who have PD and meet crossover criteria may be eligible to receive pembrolizumab for up to 17 treatment cycles. AEs are to be assessed throughout treatment and for 30 days thereafter (90 days for serious AEs) and graded per NCI CTCAE v4.0. Patients are to be followed up for survival every 9 weeks. The primary end point is PFS per RECIST v1.1; key secondary end points include OS and ORR. Enrollment in KEYNOTE-177 is ongoing. Clinical trial information: NCT02563002.

Results from a phase 2b, randomized, multicenter study of GVAX pancreas and CRS-207 compared to chemotherapy in adults with previously-treated metastatic pancreatic adenocarcinoma (ECLIPSE Study)

345

Background: GVAX is composed of irradiated, allogeneic pancreatic cancer cells modified to express GM-CSF and induce broad tumor antigen responses. Low-dose cyclophosphamide (CY) is administered with GVAX to inhibit regulatory T cells. CRS-207 is live, attenuated, double-deleted Listeria monocytogenes(LADD) engineered to express mesothelin. CRS-207 boosts T cell responses against mesothelin and stimulates innate and adaptive immunity. In an earlier Phase 2 study in patients with mPDA, CY/GVAX + CRS-207 resulted in a significant improvement in overall survival (OS) compared to CY/GVAX alone. Methods: Patients with previously-treated mPDA were randomized 1:1:1 to receive 2 doses of CY/GVAX + 4 doses of CRS-207 (Arm A), 6 doses of CRS-207 alone (Arm B), or physician’s choice of single-agent chemotherapy (Arm C). Two cohorts were included based on number of prior lines of therapy; the primary cohort (PC) represented those with ≥ 2 prior lines. The primary objective was to compare OS between Arms A and C in the PC. Additional objectives include OS analyses between all treatment arms, safety, tumor responses and immune analyses. Results: 303 patients were enrolled: 213 in the PC and 90 in an exploratory 2nd-line cohort (SC). Common AEs associated with CRS-207 treatment included transient fevers, chills, and nausea. High dropout rates were observed in Arm C prior to treatment (40% in PC, 63% in SC). Clinical trial information: NCT02004262 . Subset and immune analyses, as well as OS data from SC, will be presented at the meeting. Conclusions: The combination of CY/GVAX + CRS-207 did not show a survival benefit over chemotherapy in patients with previously-treated mPDA, although survival of patients receiving CRS-207 alone appeared similar to chemotherapy. The regimens were well tolerated with no new significant safety findings. The high dropout rate in the chemotherapy arm demonstrates a potential challenge for conventional controls in immunotherapy trials. [Table: see text]

Survival outcomes of adjuvant chemotherapy combined with radiation versus chemotherapy alone following pancreatectomy for distal pancreatic adenocarcinoma: Single institution experience

388

Background: There is limited data of survival following distal pancreatectomy and adjuvant therapy in patients with distal pancreatic adenocarcinoma. This study aimed to evaluate the survival following combined modality (chemo-radiation and chemotherapy) compared to chemotherapy alone following distal pancreatectomy (DP). Methods: Patients who underwent DP for adenocarcinoma of the body or tail of the pancreas between the years 2000 and 2015 at Johns Hopkins were included. Comparison analysis was performed between patients who received combined modality versus chemotherapy alone. Kaplan- Meier curve was used to estimate the median overall survival (OS) and the disease free survival (DFS) at 1, 3 and 5 years after pancreatectomy. Results: A total of 294 patients underwent DP at our institution. Patients were excluded if adjuvant therapy was not administered, developed metastasis prior to adjuvant therapy, had stage IV disease at the time of surgery, received neoadjuvant therapy or had inadequate follow up at our institution to assess survival outcomes. We included a total of 105 patients, of which 45 patients received chemotherapy alone and 60 patients received combined modality. The two groups were similar with respect to nodal and margin status. Patients treated with combined modality had larger > 3cm tumors (p = 0.02). Median OS with combined modality was 60.6 mo and 50.2 mo with chemotherapy only. DFS was 15.2 mo with combined modality and 17.6 mo with chemotherapy only. There was no significant difference between the groups for OS (p = 0.73) or DFS (p = 0.495). Further analysis showed a trend away from chemoradiation in the recent years. Thirty patients (29%) received multi-agent chemotherapy in the adjuvant setting. A tumor diameter > 3cm was a predictive factor for receiving chemoradiation (chi-square p value 0.02). Conclusions: There is no difference in survival with combined modality compared to chemotherapy alone as adjuvant therapy following DP. All patients in this study received adjuvant therapy. We report a higher survival than previously described which could suggest a different biology for distal tumors.

Primary Resistance to PD-1 Blockade Mediated by JAK1/2 Mutations

Loss-of-function mutations in JAK1/2 can lead to acquired resistance to anti-programmed death protein 1 (PD-1) therapy. We reasoned that they may also be involved in primary resistance to anti-PD-1 therapy. JAK1/2-inactivating mutations were noted in tumor biopsies of 1 of 23 patients with melanoma and in 1 of 16 patients with mismatch repair-deficient colon cancer treated with PD-1 blockade. Both cases had a high mutational load but did not respond to anti-PD-1 therapy. Two out of 48 human melanoma cell lines had JAK1/2 mutations, which led to a lack of PD-L1 expression upon interferon gamma exposure mediated by an inability to signal through the interferon gamma receptor pathway. JAK1/2 loss-of-function alterations in The Cancer Genome Atlas confer adverse outcomes in patients. We propose that JAK1/2 loss-of-function mutations are a genetic mechanism of lack of reactive PD-L1 expression and response to interferon gamma, leading to primary resistance to PD-1 blockade therapy.

SIGNIFICANCE

A key functional result from somatic JAK1/2 mutations in a cancer cell is the inability to respond to interferon gamma by expressing PD-L1 and many other interferon-stimulated genes. These mutations result in a genetic mechanism for the absence of reactive PD-L1 expression, and patients harboring such tumors would be unlikely to respond to PD-1 blockade therapy. Cancer Discov; 7(2); 188-201. ©2016 AACR.See related commentary by Marabelle et al., p. 128This article is highlighted in the In This Issue feature, p. 115.

Tissue-Agnostic Drug Development

The U.S. Food and Drug Administration (FDA) has approved drugs to treat patients with tumor types based on a single anatomic site, such as renal cell carcinoma or melanoma, rather than on a biomarker alone. This standard approach is based on a number of factors, including heterogeneity of drug effects in different biomarker-positive tumor types. Additionally, drug development for some drugs was primarily directed toward a specific genomic abnormality in a specific tumor type (e.g., drugs for anaplastic lymphoma kinase [ALK] fusion-positive non-small cell lung cancer). In such cases, differences in biology, differences in natural histories of different cancers, differences in mutation frequencies among cancers, or differences in concomitant therapies may have necessitated diverse development considerations. As described in U.S. regulations [21 CFR 201, CFR 201.57(c)(2)], the indications and usage section of drug labeling "must state that a drug is indicated for the treatment, prevention, mitigation, cure, or diagnosis of a recognized disease or condition or of a manifestation of a recognized disease or condition, or for the relief of symptoms associated with a recognized disease or condition." Such regulations, however, do not require that disease be defined solely as a specific tumor type. This manuscript will highlight scientific/biologic issues, clinical trial designs, and regulatory issues pertaining to the development of drugs agnostic of tumor type. Although the manuscript will discuss regulatory considerations as understood by the authors regarding tissue-agnostic drug development, it should not be considered formal or binding FDA guidance or policy.

Synthesis of triphenylamines via ligand-free selective ring-opening of benzoxazoles or benzothiazoles under superparamagnetic nanoparticle catalysis

Synthesis of triphenylamines via ligand-free selective ring-opening of benzoxazoles or benzothiazoles with aryl halides under CuFe₂O₄ superparamagnetic nanoparticle catalysis.

Microsatellite Instability as a Biomarker for PD-1 Blockade

Initial results by Le and colleagues, which were published in the June 25, 2015 issue of the New England Journal of Medicine, report significant responses of cancers with microsatellite instability (MSI) to anti-PD-1 inhibitors in patients who failed conventional therapy. This finding fits into a broader body of research associating somatic hypermutation and neoepitope formation with response to immunotherapy, with the added benefit of relying on a simple, widely used diagnostic test. This review surveys the pathogenesis and prognostic value of MSI, diagnostic guidelines for detecting it, and the frequency of MSI across tumors, with the goal of providing a reference for its use as a biomarker for PD-1 blockade. MSI usually arises from either germline mutations in components of the mismatch repair (MMR) machinery (MSH2, MSH6, MLH1, PMS2) in patients with Lynch syndrome or somatic hypermethylation of the MLH1 promoter. The result is a cancer with a 10- to 100-fold increase in mutations, associated in the colon with poor differentiation, an intense lymphocytic infiltrate, and a superior prognosis. Diagnostic approaches have evolved since the early 1990s, from relying exclusively on clinical criteria to incorporating pathologic features, PCR-based MSI testing, and immunohistochemistry for loss of MMR component expression. Tumor types can be grouped into categories based on the frequency of MSI, from colorectal (20%) and endometrial (22%-33%) to cervical (8%) and esophageal (7%) to skin and breast cancers (0%-2%). If initial results are validated, MSI testing could have an expanded role as a tool in the armamentarium of precision medicine.

Mesothelin Immunotherapy for Cancer: Ready for Prime Time?

Mesothelin is a tumor antigen that is highly expressed in many human cancers, including malignant mesothelioma and pancreatic, ovarian, and lung adenocarcinomas. It is an attractive target for cancer immunotherapy because its normal expression is limited to mesothelial cells, which are dispensable. Several antibody-based therapeutic agents as well as vaccine and T-cell therapies directed at mesothelin are undergoing clinical evaluation. These include antimesothelin immunotoxins (SS1P, RG7787/LMB-100), chimeric antimesothelin antibody (amatuximab), mesothelin-directed antibody drug conjugates (anetumab ravtansine, DMOT4039A, BMS-986148), live attenuated Listeria monocytogenes-expressing mesothelin (CRS-207, JNJ-64041757), and chimeric antigen receptor T-cell therapies. Two antimesothelin agents are currently in multicenter clinical registration trials for malignant mesothelioma: amatuximab in the first-line setting and anetumab ravtansine as second-line therapy. Phase II randomized clinical trials of CRS-207 as a boosting agent and in combination with immune checkpoint inhibition for pancreatic cancer are nearing completion. These ongoing studies will define the utility of mesothelin immunotherapy for treating cancer.

Nivolumab monotherapy in recurrent metastatic urothelial carcinoma (CheckMate 032): a multicentre, open-label, two-stage, multi-arm, phase 1/2 trial

BACKGROUND

Few effective treatments exist for patients with advanced urothelial carcinoma that has progressed after platinum-based chemotherapy. We assessed the activity and safety of nivolumab in patients with locally advanced or metastatic urothelial carcinoma whose disease progressed after previous platinum-based chemotherapy.

METHODS

In this phase 1/2, multicentre, open-label study, we enrolled patients (age ≥18 years) with urothelial carcinoma of the renal pelvis, ureter, bladder, or urethra at 16 sites in Finland, Germany, Spain, the UK, and the USA. Patients were not selected by PD-L1 expression, but tumour PD-L1 membrane expression was assessed retrospectively. Patients received nivolumab 3 mg/kg intravenously every 2 weeks until disease progression or treatment discontinuation because of unacceptable toxicity or other protocol-defined reasons, whichever occurred later. The primary endpoint was objective response by investigator assessment. All patients who received at least one dose of the study drug were included in the analyses. We report an interim analysis of this ongoing trial. CheckMate 032 is registered with ClinicalTrials.gov, NCT01928394.

FINDINGS

Between June 5, 2014, and April 24, 2015, 86 patients with metastatic urothelial carcinoma were enrolled in the nivolumab monotherapy group and 78 received at least one dose of treatment. At data cutoff (March 24, 2016), the minimum follow-up was 9 months (median 15·2 months, IQR 12·9-16·8). A confirmed investigator-assessed objective response was achieved in 19 (24·4%, 95% CI 15·3-35·4) of 78 patients. Grade 3-4 treatment-related adverse events occurred in 17 (22%) of 78 patients; the most common were elevated lipase (four [5%]), elevated amylase (three [4%]), and fatigue, maculopapular rash, dyspnoea, decreased lymphocyte count, and decreased neutrophil count (two [3%] each). Serious adverse events were reported in 36 (46%) of 78 patients and eight (10%) had a serious adverse event judged to be treatment related. Two (3%) of 78 patients discontinued because of treatment-related adverse events (grade 4 pneumonitis and grade 4 thrombocytopenia) and subsequently died.

INTERPRETATION

Nivolumab monotherapy was associated with a substantial and durable clinical response and a manageable safety profile in previously treated patients with locally advanced or metastatic urothelial carcinoma. These data support further investigation of nivolumab monotherapy in advanced urothelial carcinoma.

FUNDING

Bristol-Myers Squibb.

Mutational profiling of colorectal cancers with microsatellite instability

Microsatellite instability (MSI) is caused by defective mismatch repair in 15–20% of colorectal cancers (CRCs). Higher mutation loads in tumors with mismatch repair deficiency can predict response to pembrolizumab, an anti-programmed death 1 (PD-1) immune checkpoint inhibitor. We analyzed the mutations in 113 CRCs without MSI (MSS) and 29 CRCs with MSI-High (MSI-H) using the 50-gene AmpliSeq cancer panel. Overall, MSI-H CRCs showed significantly higher mutations than MSS CRCs, including insertion/deletion mutations at repeat regions. MSI-H CRCs showed higher incidences of mutations in the BRAF, PIK3CA, and PTEN genes as well as mutations in the receptor tyrosine kinase families. While the increased mutations in BRAF and PTEN in MSI-H CRCs are well accepted, we also support findings of mutations in the mTOR pathway and receptor tyrosine kinase family genes. MSS CRCs showed higher incidences of mutations in the APC, KRAS and TP53 genes, confirming previous findings. NGS assays may be designed to detect driver mutations for targeted therapeutics and to identify tumors with high mutation loads for potential treatment with immune checkpoint blockade therapies. Further studies may be warranted to elucidate potential targeted therapeutics against mutations in the mTOR pathway and the receptor tyrosine kinase family in MSI-H CRCs as well as the benefit of anti-PD-1 immunotherapy in hypermutated MSS CRCs or other cancers.

Mismatch Repair Deficiency and Response to Immune Checkpoint Blockade

: More than 1.6 million new cases of cancer will be diagnosed in the U.S. in 2016, resulting in more than 500,000 deaths. Although chemotherapy has been the mainstay of treatment in advanced cancers, immunotherapy development, particularly with PD-1 inhibitors, has changed the face of treatment for a number of tumor types. One example is the subset of tumors characterized by mismatch repair deficiency and microsatellite instability that are highly sensitive to PD-1 blockade. Hereditary forms of cancer have been noted for more than a century, but the molecular changes underlying mismatch repair-deficient tumors and subsequent microsatellite unstable tumors was not known until the early 1990s. In this review article, we discuss the history and pathophysiology of mismatch repair, the process of testing for mismatch repair deficiency and microsatellite instability, and the role of immunotherapy in this subset of cancers.

IMPLICATIONS FOR PRACTICE

Mismatch repair deficiency has contributed to our understanding of carcinogenesis for the past 2 decades and now identifies a subgroup of traditionally chemotherapy-insensitive solid tumors as sensitive to PD-1 blockade. This article seeks to educate oncologists regarding the nature of mismatch repair deficiency, its impact in multiple tumor types, and its implications for predicting the responsiveness of solid tumors to immune checkpoint blockade.

Nivolumab alone and nivolumab plus ipilimumab in recurrent small-cell lung cancer (CheckMate 032): a multicentre, open-label, phase 1/2 trial

BACKGROUND

Treatments for small-cell lung cancer (SCLC) after failure of platinum-based chemotherapy are limited. We assessed safety and activity of nivolumab and nivolumab plus ipilimumab in patients with SCLC who progressed after one or more previous regimens.

METHODS

The SCLC cohort of this phase 1/2 multicentre, multi-arm, open-label trial was conducted at 23 sites (academic centres and hospitals) in six countries. Eligible patients were 18 years of age or older, had limited-stage or extensive-stage SCLC, and had disease progression after at least one previous platinum-containing regimen. Patients received nivolumab (3 mg/kg bodyweight intravenously) every 2 weeks (given until disease progression or unacceptable toxicity), or nivolumab plus ipilimumab (1 mg/kg plus 1 mg/kg, 1 mg/kg plus 3 mg/kg, or 3 mg/kg plus 1 mg/kg, intravenously) every 3 weeks for four cycles, followed by nivolumab 3 mg/kg every 2 weeks. Patients were either assigned to nivolumab monotherapy or assessed in a dose-escalating safety phase for the nivolumab/ipilimumab combination beginning at nivolumab 1 mg/kg plus ipilimumab 1 mg/kg. Depending on tolerability, patients were then assigned to nivolumab 1 mg/kg plus ipilimumab 3 mg/kg or nivolumab 3 mg/kg plus ipilimumab 1 mg/kg. The primary endpoint was objective response by investigator assessment. All analyses included patients who were enrolled at least 90 days before database lock. This trial is ongoing; here, we report an interim analysis of the SCLC cohort. This study is registered with ClinicalTrials.gov, number NCT01928394.

FINDINGS

Between Nov 18, 2013, and July 28, 2015, 216 patients were enrolled and treated (98 with nivolumab 3 mg/kg, three with nivolumab 1 mg/kg plus ipilimumab 1 mg/kg, 61 with nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, and 54 with nivolumab 3 mg/kg plus ipilimumab 1 mg/kg). At database lock on Nov 6, 2015, median follow-up for patients continuing in the study (including those who had died or discontinued treatment) was 198·5 days (IQR 163·0-464·0) for nivolumab 3 mg/kg, 302 days (IQR not calculable) for nivolumab 1 mg/kg plus ipilimumab 1 mg/kg, 361·0 days (273·0-470·0) for nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, and 260·5 days (248·0-288·0) for nivolumab 3 mg/kg plus ipilimumab 1 mg/kg. An objective response was achieved in ten (10%) of 98 patients receiving nivolumab 3 mg/kg, one (33%) of three patients receiving nivolumab 1 mg/kg plus ipilimumab 1 mg/kg, 14 (23%) of 61 receiving nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, and ten (19%) of 54 receiving nivolumab 3 mg/kg plus ipilimumab 1 mg/kg. Grade 3 or 4 treatment-related adverse events occurred in 13 (13%) patients in the nivolumab 3 mg/kg cohort, 18 (30%) in the nivolumab 1 mg/kg plus ipilimumab 3 mg/kg cohort, and ten (19%) in the nivolumab 3 mg/kg plus ipilimumab 1 mg/kg cohort; the most commonly reported grade 3 or 4 treatment-related adverse events were increased lipase (none vs 5 [8%] vs none) and diarrhoea (none vs 3 [5%] vs 1 [2%]). No patients in the nivolumab 1 mg/kg plus ipilimumab 1 mg/kg cohort had a grade 3 or 4 treatment-related adverse event. Six (6%) patients in the nivolumab 3 mg/kg group, seven (11%) in the nivolumab 1 mg/kg plus ipilimumab 3 mg/kg group, and four (7%) in the nivolumab 3 mg/kg plus ipilimumab 1 mg/kg group discontinued treatment due to treatment-related adverse events. Two patients who received nivolumab 1 mg/kg plus ipilimumab 3 mg/kg died from treatment-related adverse events (myasthenia gravis and worsening of renal failure), and one patient who received nivolumab 3 mg/kg plus ipilimumab 1 mg/kg died from treatment-related pneumonitis.

INTERPRETATION

Nivolumab monotherapy and nivolumab plus ipilimumab showed antitumour activity with durable responses and manageable safety profiles in previously treated patients with SCLC. These data suggest a potential new treatment approach for a population of patients with limited treatment options and support the evaluation of nivolumab and nivolumab plus ipilimumab in phase 3 randomised controlled trials in SCLC.

FUNDING

Bristol-Myers Squibb.

Clinicopathological features of acute kidney injury associated with immune checkpoint inhibitors

Immune checkpoint inhibitors (CPIs), monoclonal antibodies that target inhibitory receptors expressed on T cells, represent an emerging class of immunotherapy used in treating solid organ and hematologic malignancies. We describe the clinical and histologic features of 13 patients with CPI-induced acute kidney injury (AKI) who underwent kidney biopsy. Median time from initiation of a CPI to AKI was 91 (range, 21 to 245) days. Pyuria was present in 8 patients, and the median urine protein to creatinine ratio was 0.48 (range, 0.12 to 0.98) g/g. An extrarenal immune-related adverse event occurred prior to the onset of AKI in 7 patients. Median peak serum creatinine was 4.5 (interquartile range, 3.6-7.3) mg/dl with 4 patients requiring hemodialysis. The prevalent pathologic lesion was acute tubulointerstitial nephritis in 12 patients, with 3 having granulomatous features, and 1 thrombotic microangiopathy. Among the 12 patients with acute tubulointerstitial nephritis, 10 received treatment with glucocorticoids, resulting in complete or partial improvement in renal function in 2 and 7 patients, respectively. However, the 2 patients with acute tubulointerstitial nephritis not given glucocorticoids had no improvement in renal function. Thus, CPI-induced AKI is a new entity that presents with clinical and histologic features similar to other causes of drug-induced acute tubulointerstitial nephritis, though with a longer latency period. Glucocorticoids appear to be a potentially effective treatment strategy. Hence, AKI due to CPIs may be caused by a unique mechanism of action linked to reprogramming of the immune system, leading to loss of tolerance.

Synthesis of 1,2-Dicarbonyl-3-enes by Hydroacylation of 1-Alkynes with Glyoxal Derivatives Using Metal-Organic Framework Cu/MOF-74 as Heterogeneous Catalyst

A crystalline copper-based metal-organic framework Cu/MOF-74 was synthesized, and used as an efficient heterogeneous catalyst for the synthesis of 1,2-dicarbonyl-3-enes by means of the hydroacylation of 1-alkynes with glyoxal derivatives in the presence of a base. Cu/MOF-74 was found to be more catalytically active for the synthesis of 1,2-dicarbonyl-3-enes than other MOFs including Cu₂ (BDC)₂ (DABCO), Cu₃ (BTC)₂ , Cu(BDC), Cu₂ (NDC)₂ (DABCO), Cu₄ I₄ (DABCO)₂ , Ni-MOF-74, Zn-MOF-74, Fe₃ O(BDC)₃ , In(OH)(BDC), and Zr₆ O₄ (OH)₄ (BDC)₆ . Cu/MOF-74 also exhibited better performance than other homogeneous copper catalysts, including Cu(OAc)₂ , Cu(NO₃ )₂ , CuI, CuBr, CuCl, CuCl₂ , and CuBr₂ . The Cu/MOF catalyst was able to be recovered and reused several times without a significant degradation in catalytic activity. To the best of our knowledge, the formation of 1,2-dicarbonyl-3-enes has not previously been carried out under heterogeneous catalysis conditions.

Using Quantitative Seroproteomics to Identify Antibody Biomarkers in Pancreatic Cancer

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States. Less than 6% of patients survive beyond the fifth year due to inadequate early diagnostics and ineffective treatment options. Our laboratory has developed an allogeneic, granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting pancreatic cancer vaccine (GVAX) that has been tested in phase II clinical trials. Here, we employed a serum antibodies-based SILAC immunoprecipitation (SASI) approach to identify proteins that elicit an antibody response after vaccination. The SASI approach uses immunoprecipitation with patient-derived antibodies that is coupled to quantitative stable isotope-labeled amino acids in cell culture (SILAC). Using mass spectrometric analysis, we identified more than 150 different proteins that induce an antibody response after vaccination. The regulatory subunit 12A of protein phosphatase 1 (MYPT1 or PPP1R12A), regulatory subunit 8 of the 26S proteasome (PSMC5), and the transferrin receptor (TFRC) were shown to be pancreatic cancer-associated antigens recognized by postvaccination antibodies in the sera of patients with favorable disease-free survival after GVAX therapy. We further interrogated these proteins in over 80 GVAX-treated patients' pancreases and uniformly found a significant increase in the expression of MYPT1, PSMC5, and TFRC in neoplastic compared with non-neoplastic pancreatic ductal epithelium. We show that the novel SASI approach can identify antibody targets specifically expressed in patients with improved disease-free survival after cancer vaccine therapy. These targets need further validation to be considered as possible pancreatic cancer biomarkers.

Impact of stereotactic body radiation therapy on patient-reported quality of life in patients with unresectable or recurrent pancreatic cancer

413

Background: The impact of fractionated stereotactic body radiation therapy (SBRT) on patient-reported quality of life (QOL) and physician-reported toxicity in patients with recurrent or locally advanced pancreatic cancer (PCA) was prospectively evaluated. Methods: Forty-two PCA patients were treated with 25-33 Gy using SBRT in 5 fractions on a single-institution study. Both patient- and physician-reported outcomes were evaluated prior to SBRT and 4-6 weeks post-SBRT. Eight outcomes were consistently evaluated among both groups—performance status, fatigue, pain, anorexia, nausea, vomiting, constipation, and diarrhea. Patient-reported QOL metrics were assessed using a 4-point Likert scale on the EORTC QLQ-C30 and QLQ-PAN26, while physician-reported toxicities were graded using the NCI CTCAE version 4.0. Comparisons between those with paired patient- and physician-reported outcomes collected prior to and 4-6 weeks after SBRT were made using the Wilcoxon signed-rank test. Results: Of the 42 patients currently enrolled onto the study, 29 had both patient- and physician-reported outcomes collected prior to and 4-6 weeks after SBRT. Fifty-five percent were female and 83% were Caucasian. The median age at diagnosis was 65.6 years (range, 40.8-86.6). There was no significant impairment of any of the 8 physician-reported toxicities, nor were significant changes observed in patient-reported overall health (p = 0.66) or QOL (p = 0.18) scores following SBRT. Patients felt less worried about their future health (mean change [mD] = -0.45, p = 0.02), and an improvement in feeling less attractive as a result of disease and treatment reached borderline significance (mD= 0.31, p = 0.09). However, patients felt limited in planning activities in advance (mD= 0.45, p = 0.02) and were more constipated (mD= 0.38, p = 0.01) 4-6 weeks post-SBRT. Conclusions: Although the numbers are small, patients with unresectable or locally recurrent PCA do not appear to suffer any detriment of overall health or QOL after receiving a five-day course of SBRT. Moreover, this regimen may lead to a more optimistic point of view on future health and/or level of physical attraction. Clinical trial information: NCT01781728.

Randomized phase II study of the safety, efficacy, and immune response of GVAX pancreas (with cyclophosphamide) and CRS-207 with or without nivolumab in patients with previously treated metastatic pancreatic adenocarcinoma (STELLAR)

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.

KEYNOTE-164: Phase II study of pembrolizumab (MK-3475) for patients with previously treated, microsatellite instability-high advanced colorectal carcinoma

TPS787

Background: A subset of advanced colorectal cancers (CRC) is characterized by mismatch repair (MMR) deficiency leading to a microsatellite instability-high (MSI-H) phenotype, which is characterized by a high mutational burden and lymphocytic infiltrates. Pembrolizumab is a monoclonal anti–PD-1 antibody designed to block the interaction between PD-1 and its ligands PD-L1 and PD-L2. In the phase II KEYNOTE-016 study, pembrolizumab provided an ORR of 62% in patients (pts) with progressive MMR-deficient metastatic CRC vs 0% in pts with MMR-proficient CRC. The multicenter, phase II KEYNOTE-164 trial (NCT02460198) will evaluate the efficacy and safety of pembrolizumab in pts with previously treated, advanced MSI-H CRC. Methods: Key eligibility criteria include age ≥ 18 y; advanced CRC; MSI-H phenotype evidenced by ≥ 2 allelic shifts using a PCR-based assay or lack of expression of ≥ 1 MMR protein (MLH1, MSH2, MSH6, PMS2) by IHC; prior treatment with a fluoropyrimidine, oxaliplatin, irinotecan, bevacizumab, and, if KRAS and NRAS wild type, cetuximab or panitumumab; ECOG PS 0-1; no active autoimmune disease or brain metastases; and no prior anticancer therapy within 2 wk of study treatment. Pembrolizumab 200 mg Q3W will be administered for 35 cycles or until disease progression, unacceptable toxicity, pt withdrawal, or investigator decision. Clinically stable pts with RECIST-defined progression may continue pembrolizumab until a scan performed ≥ 4 wk later confirms progression. Pts who complete all 35 cycles or who discontinue pembrolizumab following a complete response and experience progression may be eligible for 1 y of pembrolizumab retreatment. Response will be evaluated every 9 wk per RECIST v1.1 by central review and per RECIST adapted for immunotherapy response patterns. AEs will be assessed throughout treatment and for 30 d thereafter (up to 90 d for serious AEs) and graded per NCI CTCAE v4.0. Pts will be followed for survival every 2 mo. ORR per RECIST v1.1 by central review is the primary end point; secondary end points include PFS, OS, disease control rate, and duration of response. Enrollment is ongoing and will continue until ~60 pts have enrolled. Clinical trial information: NCT02460198.

Safety and activity of nivolumab monotherapy in advanced and metastatic (A/M) gastric or gastroesophageal junction cancer (GC/GEC): Results from the CheckMate-032 study

6

Background: Patients (pts) with GC/GEC often present with A/M disease, which has a poor prognosis, with 1-year survival < 30%, and few treatment options. Nivolumab is a fully human anti-PD-1 IgG4 monoclonal antibody with a favorable safety profile and efficacy in melanoma, non–small-cell lung cancer, and renal cell carcinoma. The phase I/II, open-label CheckMate-032 study evaluated nivolumab ± ipilimumab in pts with solid tumors. Here, we report initial results for pts with GEC/GC receiving nivolumab monotherapy. Methods: Pts with A/M histologically confirmed GC/GEC, irrespective of PD-L1 status, were assigned to receive nivolumab alone (3 mg/kg IV Q2W) and treated until disease progression (PD) or intolerable toxicity. The primary endpoint was objective response rate (ORR); other endpoints included safety, progression-free survival, overall survival (OS), and biomarker status. Results: 59 pts were enrolled and treated with single-agent nivolumab. Median age was 60 y (range 29–80), and 83% of pts received ≥ 2 prior regimens. At database lock, 10 pts were on active treatment; 49 pts discontinued (PD, n = 40; unrelated adverse events, n = 4; treatment-related adverse events [TRAEs], n = 2; other, n = 3). Pts received a median of 4 doses (range 1–25). ORR was 12% (n = 7/58; 1 complete response, 6 partial responses); 12 pts (21%) had stable disease. Among responders, median duration of response was 7.1 mo (95% CI, 3.0–13.2). Median OS was 6.8 mo (95% CI, 3.3–12.4); 12-mo OS rate was 38% (95% CI, 23.2–52.7). 39% of tumor samples were PD-L1 positive ( ≥ 1% cutoff). ORRs in pts with PD-L1-positive and -negative tumors were 18% and 12%, respectively. TRAEs occurred in 66% of pts; most were Grade 1/2. Grade 3/4 TRAEs occurred in 14% of pts and included pneumonitis, fatigue, diarrhea, vomiting, hypothyroidism, and increased aspartate and alanine aminotransferase and alkaline phosphatase levels. No treatment-related deaths occurred. Conclusions: Nivolumab monotherapy was well tolerated and demonstrated encouraging antitumor activity in heavily pretreated pts with GC/GEC. Objective responses occurred in pts with PD-L1-positive and -negative tumors. Clinical trial information: NCT01928394.

KEYNOTE-177: First-line, open-label, randomized, phase III study of pembrolizumab (MK-3475) versus investigator-choice chemotherapy for mismatch repair deficient or microsatellite instability-high metastatic colorectal carcinoma

TPS789

Background: Mismatch repair deficient (dMMR) tumors are characterized by high mutational load and lymphocyte infiltration and may be good candidates for immune checkpoint blockade. Pembrolizumab is a monoclonal antibody against PD-1 that is designed to block its interaction with PD-L1 and PD-L2 and thus allow an antitumor immune response. In the KEYNOTE-016 proof-of-concept study, pembrolizumab showed promising antitumor activity against dMMR tumors in patients (pts) with treatment-refractory metastatic colorectal carcinoma (mCRC). KEYNOTE-177 is an international, randomized trial designed to evaluate the efficacy and safety of pembrolizumab compared with standard-of-care (SOC) chemotherapy in the first-line setting for dMMR or microsatellite instability-high (MSI-H) mCRC. Methods: Key eligibility criteria include age ≥ 18 y, confirmed MSI-H or dMMR mCRC, ECOG PS 0-1, no active autoimmune disease or brain metastases, and no prior therapy for metastatic disease. Pts will be randomized 1:1 to receive either pembrolizumab 200 mg Q3W or investigator’s choice of SOC chemotherapy. Chemotherapy must be chosen prior to randomization; options include mFOLFOX6 or FOLFIRI alone or in combination with bevacizumab or cetuximab. Treatment will continue until PD, unacceptable toxicity, pt/investigator decision, or completion of 35 cycles (pembrolizumab only). Response will be evaluated every 9 wk per RECIST v1.1 by central review and per RECIST adapted for immunotherapy response patterns. Eligible pts may continue pembrolizumab beyond initial RECIST-defined progression. Pts in the SOC arm who have PD and meet crossover criteria may be eligible to receive pembrolizumab for up to 17 treatment cycles. AEs will be assessed throughout treatment and for 30 d thereafter (up to 90 d for serious AEs) and graded per NCI CTCAE v4.0. Pts will be followed for survival every 9 wk. PFS per RECIST v1.1 is the primary end point; OS and ORR are key secondary end points. Other end points include duration of response and health-related quality of life. Planned enrollment in KEYNOTE-177 is 270 pts.

A prospective study evaluating stereotactic body radiation therapy in unresectable, recurrent, or residual pancreatic adenocarcinoma

454

Background: The purpose of this prospective, non-randomized phase II single-institution study was to evaluate if local control can be achieved with reasonable acute and late GI toxicity using fractionated SBRT in patients with unresectable, recurrent, or residual locally advanced pancreatic cancer (LAPC). Methods: A total of 24 patients with LAPC were enrolled from June 2013 to August 2014. Eligibility required stability after induction chemotherapy or residual disease or local failure after surgery. Induction chemotherapy regimens consisted of: (1) gemcitabine alone (8%); (2) gemcitabine-based regimens (17%); (3) FOLFIRINOX-based regimens (63%); or (4) combination regimens (13%). Chemotherapy was discontinued one week prior to SBRT. Patients received a median cumulative dose of 33 Gy in 5 fractions (5-6.6 Gy/fraction). Patients were permitted to resume chemotherapy one week post-SBRT. Toxicity was assessed using the NCI CTCAE version 4.0. Results: Of the 24 patients, 58% were male and 50% had tumors in the head of the pancreas. Median age at diagnosis was 66.8 years, and median follow-up from the date of diagnosis was 11.9 months (range, 7.4-29.7 months). There have not been any acute or late grade ≥ 2 gastritis, enteritis, fistula, or ulcer toxicities (primary endpoint). Median OS has not yet been reached, median LPFS was 19.3 months (95% CI, 12.3-14.8), median DMFS was 13.6 months (95% CI, 9.2-17.9) and median PFS was 13.6 months (95% CI, 13.5-25.2). Plasma CA 19-9 level was non-significantly reduced after SBRT, displaying a -9.15 average percent change from baseline (median time after SBRT, 1.2 months). FFLP at 1 year was 83.9%. Eight (33%) patients underwent successful surgery following SBRT, with rates of both margin- and node-negative resection being 75%. Conclusions: Chemotherapy followed by fractionated SBRT results in favorable local control and survival with minimal acute and late GI toxicity. A notable proportion of patients initially deemed unresectable underwent successful resection. This study suggests that SBRT can be safely given following more aggressive multiagent chemotherapy in patients with LAPC. Clinical trial information: NCT01781728.

PD-1 blockade in mismatch repair deficient non-colorectal gastrointestinal cancers

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.

Clinical and immune characteristics of rapid dropout and long-term survival in a phase II safety and efficacy study of combination CRS-207/GVAX immunotherapy in pancreatic cancer

459

Background: Baseline patient characteristics may impact duration on study and survivorship of patients in immunotherapy trials. In this study, GVAX pancreas (GM-CSF–secreting allogeneic pancreatic tumor cells) was administered with low-dose cyclophosphamide (Cy), with or without subsequent CRS-207 (live-attenuated Listeria monocytogenes–expressing mesothelin) infusion. Baseline clinical and immunological data were examined for two patient subsets based on duration on study. Methods: Previously treated patients with metastatic pancreatic adenocarcinoma were randomly assigned at a ratio of 2:1 to 2 doses of Cy/GVAX followed by 4 doses of CRS-207 or 6 doses of Cy/GVAX every 3 weeks. Stable patients were offered additional courses. Patients were evaluated for post-randomization duration on study of < 60 days (rapid dropouts, RD) and > 18 months (long-term survivors, LTS). Baseline characteristics of these subsets were examined. Results: A total of 93 patients were randomized. Fifteen patients were RD; 13 were LTS. More RDs versus LTS had liver metastasis and lymph node involvement. On average, fewer RD patients had radiotherapy prior to randomization and fewer had prior surgical intervention. RD averaged 1.73 prior metastatic cancer treatment regimens versus 1.31 in LTS. RD also had higher average baseline CA 19-9 levels. Immune analysis showed higher circulating terminal effector CD8+ T cells and lower serum IL-6 in LTS compared to RD. Serum IL-6 concentration remained lower in LTS at four weeks following initiation of treatment. For patients who received CRS-207, CD8+ T cells specific to listeriolysin O (LLO) and mesothelin were higher in LTS than RD, as determined by ELISPOT. Conclusions: Baseline clinical and immunological characteristics may impact patient duration on immunotherapy trials. Immune monitoring and biomarker analysis in this study is ongoing to identify circulating cellular, tumor biomarkers and genomic (miRNA and mRNA) signatures that may correlate with survival. These findings warrant continued exploration of patient characteristics to identify best candidates for immunotherapy trials. Clinical trial information: NCT01417000.