1239P - High level of activity of nivolumab anti-PD-1 immunotherapy and favorable outcome in metastatic/refractory MSI-H non-colorectal cancer: Results of the MSI cohort from the French AcSé program

Abstract

Abstract Background Microsatellite instability-high (MSI-H) is observed in a large variety of cancer types. Immune checkpoint targeted therapies against PD-1 and CTLA-4 have demonstrated significant activity in metastatic colorectal cancer (mCRC) with nivolumab +/- ipilimumab. We aimed to demonstrate a clinical benefit of nivolumab in non-CRC MSI patients. Methods The AcSe immunotherapy program launched by the French National Cancer Institute (INCa) and sponsored by the French network of comprehensive cancer centers (Unicancer) is a nationwide exploratory program which has allowed access to anti-PD-1 therapies outside of their current approvals. A phase II, single arm, AcSe-nivolumab trial has been conducted to investigate the efficacy and tolerance of nivolumab in patients with metastastic/refractory rare tumor types. Here we report the results of the MSI cohort. Nivolumab (240 mg IV) was administered q2w for a max of 2 years or until disease progression (PD), or toxicity. The primary endpoint was the objective response rate (ORR) assessed by RECIST v1.1 at 12 weeks. Results From July 2017 to October 2018, 50 pts (mean age 63 years) were included. Primary locations were endometrial adenoCa (17), gastric (10), small bowel (7), pancreas (5), biliary (4), urothelial (2), ovary (2), and breast (2). 15 patients (30%) had a Lynch syndrome. All patients were pre-treated (mean of previous lines: 1.6) and had a MSI status locally determined by IHC and/or PCR (IHC 15 pts, PCR 4, both 31). The mean number of cycles/patients was 12.9. The ORR at 12 weeks was 38% (95%CI 24.6 to 52.8) and the best ORR at any time was 42% (95%CI, 28.2 to 56.8) with median time to response of 14 weeks. CR: n = 2; PR: n = 17; SD: n = 16; DCR=74%. Median PFS was not reached with a 6-mo PFS at 58.9% (95%CI, 46.5 to 74.6). At the date of analysis, 15 patients died (PD 13, drug related death 1, other 1), with a 6-mo OS rate at 80.3% (95%CI, 69.5 to 92.8). No unexpected adverse event of nivolumab has been observed. Conclusions Nivolumab as monotherapy is highly active in non-colorectal MSI patients, outperforming results of classical chemotherapy in this heavily pre-treated population. Clinical trial identification NCT03012581, EudraCT 2016-002257-37. Legal entity responsible for the study RD Honoraria (institution), Travel / Accommodation / Expenses: MSD; Advisory / Consultancy: Roche; Honoraria (self), Advisory / Consultancy: Sanofi; Honoraria (institution), Travel / Accommodation / Expenses: BMS. E. Saada-Bouzid: Advisory / Consultancy: BMS; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Merck Serono. D. Pouessel: Advisory / Consultancy, Travel / Accommodation / Expenses: AstraZeneca; Advisory / Consultancy: Sanofi; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy: Astellas; Advisory / Consultancy, Research grant / Funding (institution): Janssen; Research grant / Funding (institution): MSD; Research grant / Funding (institution): Roche; Research grant / Funding (institution): Incyte; Research grant / Funding (institution): A2; Speaker Bureau / Expert testimony: Ipsen; Speaker Bureau / Expert testimony: BMS. C. Le Tourneau: Advisory / Consultancy: MSD; Advisory / Consultancy: BMS; Advisory / Consultancy: Merck Serono; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Nanobiotix; Advisory / Consultancy: Roche; Advisory / Consultancy: Amgen; Advisory / Consultancy: GSK. P. Augereau: Advisory / Consultancy: Pfizer; Advisory / Consultancy: AstraZeneca. J. Soria: Advisory / Consultancy, Shareholder / Stockholder / Stock options, Full / Part-time employment: AstraZeneca; Shareholder / Stockholder / Stock options: Gritstone; Advisory / Consultancy: Astex; Advisory / Consultancy: Clovis; Advisory / Consultancy: GSK; Advisory / Consultancy: GammaMabs; Advisory / Consultancy: Lilly; Advisory / Consultancy: MSD; Advisory / Consultancy: Mission Therapeutics; Advisory / Consultancy: Merus; Advisory / Consultancy: Pfizer; Advisory / Consultancy: PharmaMar; Advisory / Consultancy: Pierre Fabre; Advisory / Consultancy: Roche/Genentech; Advisory / Consultancy: Sanofi; Advisory / Consultancy: Servier; Advisory / Consultancy: Symphogen; Advisory / Consultancy: Takeda. A. Marabelle: Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self): BMS; Research grant / Funding (self): Boehringer Ingelheim; Research grant / Funding (self): Fondation MSD Avenir; Advisory / Consultancy: Oncovir; Advisory / Consultancy, Speaker Bureau / Expert testimony: Merck Serono; Advisory / Consultancy: eTheRNA; Advisory / Consultancy, Research grant / Funding (self): Lytix pharma; Advisory / Consultancy: Kyowa Kirin Pharma; Advisory / Consultancy: Novartis, Seattle Genetics, Molecular Partners; Advisory / Consultancy: Symphogen, Bayer, Partner Therapeutics; Advisory / Consultancy: Genmab, RedX pharma, OSE Immunotherapeutics; Advisory / Consultancy, Speaker Bureau / Expert testimony: Amgen, Sanofi, Servier; Advisory / Consultancy: Biothera, Gritstone; Advisory / Consultancy: Nektar, Pierre Fabre; Advisory / Consultancy: GSK; Advisory / Consultancy: Oncosec; Advisory / Consultancy, Research grant / Funding (self): Pfizer; Speaker Bureau / Expert testimony, Research grant / Funding (self): MSD; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self): AstraZeneca/MedImmune; Speaker Bureau / Expert testimony, Research grant / Funding (self): Roche/Genentech. All other authors have declared no conflicts of interest.