Ipilimumab plus nivolumab in avelumab-refractory Merkel cell carcinoma: a multicenter study of the prospective skin cancer registry ADOREG.

Merkel cell carcinoma is a rare, highly aggressive skin cancer with neuroendocrine differentiation. Immune checkpoint inhibition has significantly improved treatment outcomes in metastatic disease with response rates to programmed cell death protein 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) inhibition of up to 62%. However, primary and secondary resistance to PD-1/PD-L1 inhibition remains a so far unsolved clinical challenge since effective and safe treatment options for these patients are lacking.Fourteen patients with advanced (non-resectable stage III or stage IV, Union international contre le cancer 2017) Merkel cell carcinoma with primary resistance to the PD-L1 inhibitor avelumab receiving subsequent therapy (second or later line) with ipilimumab plus nivolumab (IPI/NIVO) were identified in the prospective multicenter skin cancer registry ADOREG. Five of these 14 patients were reported previously and were included in this analysis with additional follow-up. Overall response rate, progression-free survival (PFS), overall survival (OS) and adverse events were analyzed.All 14 patients received avelumab as first-line treatment. Thereof, 12 patients had shown primary resistance with progressive disease in the first tumor assessment, while two patients had initially experienced a short-lived stabilization (stable disease). Six patients had at least one systemic treatment in between avelumab and IPI/NIVO. In total, 7 patients responded to IPI/NIVO (overall response rate 50%), and response was ongoing in 4 responders at last follow-up. After a median follow-up of 18.85 months, median PFS was 5.07 months (95% CI 2.43-not available (NA)), and median OS was not reached. PFS rates at 12 months and 24 months were 42.9% and 26.8 %, respectively. The OS rate at 36 months was 64.3%. Only 3 (21%) patients did not receive all 4 cycles of IPI/NIVO due to immune-related adverse events.In this multicenter evaluation, we observed high response rates, a durable benefit and promising OS rates after treatment with later-line combined IPI/NIVO. In conclusion, our patient cohort supports our prior findings with an encouraging activity of second-line or later-line IPI/NIVO in patients with anti-PD-L1-refractory Merkel cell carcinoma.
Competing Interests: Competing interests: VG has received honoraria from Bristol-Myers Squibb and reports travel support from Novartis, Pierre Fabre Pharmaceuticals, Bristol-Myers Squibb, Merck Sharp & Dohme, Sanofi Genzyme and SUN Pharmaceuticals Industries, outside the submitted work. PS has received honoraria from Bristol-Myers Squibb, an institutional research grant from Novartis, reports travel support from Bristol-Myers Squibb, Lilly, Sanofi-Aventis, Novartis, Pierre Fabre Pharmaceuticals and Sun Pharmaceuticals. HK declares no conflicts of interest. AG speaker's honoraria from Allmiral, Bristol-Myers Squibb, MSD Sharp & Dohme and Roche; intermittent advisory board relationships with Amgen, Bristol-Myers Squibb, Novartis, MSD Sharp & Dohme, Pierre Fabre Pharmaceuticals, Pfizer, Roche and Sanofi Genzyme; travel and congress fee support from Bristol-Myers Squibb, MSD Sharp & Dohme, Novartis, Pierre Fabre Pharmaceuticals and Roche. Clinical studies: Amgen, Array, Bristol-Myers Squibb, GSK, Novartis, Merck, MSD Sharp & Dohme, Pfizer and Roche. MG has received speaker’s and advisory board honoraria from Argenx, Biotest, GSK, Janssen, Leo Pharma, Lilly, Novartis and UCB outside the submitted work. DK declares no conflicts of interest. CP received honoraria and travel support from BMS, MSD, Pierre-Fabre, Sanofi, MERCK, SunPharma, Pelpharma, Almirall, and Novartis outside the submitted work. CG is on the advisory board or has received honoraria from Almirall, Amgen, Beiersdorf, BioNTech, Bristol-Myers Squibb, Immunocore, Janssen, MSD Sharp & Dohme, Novartis, Pierre-Fabre Pharma, Roche, Sanofi Genzyme, SUN Pharma and Sysmex Inostics, research funding from Novartis and Sanofi Genzyme, and travel support from Bristol-Myers Squibb, Pierre Fabre Pharma and SUN Pharma, outside the submitted work; he is co-founder of Dermagnostix and Dermagnostix R&D and holds leadership roles for DeCOG, Hiege-Stiftung and Roggenbuck Stiftung. SH has received speaker and advisory board honoraria from Bristol-Myers Squibb and MSD Sharp & Dohme. LZ served as consultant and/or has received honoraria from Bristol-Myers Squibb, Merck Sharp & Dohme, Novartis, Pierre-Fabre, Sunpharma and Sanofi; Research funding to institution: Novartis; travel support from Merck Sharp & Dohme, Bristol-Myers Squibb, Amgen, Pierre-Fabre, Sunpharma, Sanofi and Novartis, outside the submitted work. JCB is receiving speaker’s bureau honoraria from Amgen, Pfizer, Recordati and Sanofi, is a paid consultant/advisory board member/DSMB member for Almirall, Boehringer Ingelheim, InProTher, ICON, MerckSerono, Pfizer, 4SC, and Sanofi/Regeneron. His group receives research grants from Bristol-Myers Squibb, Merck Serono, HTG, IQVIA, and Alcedis. UL is receiving speaker’s honoraria from Sanofi, Sun Pharma, is a paid advisory board member Almirall, Sanofi/Regeneron, Sun Pharma, MSD, Novartis and Roche and gets travel support from Sun Pharma and Sanofi. Her group receives research grants from MSD outside the submitted work. MW declares research support from BMS and MSD; speaker and/or advisory board honoraria from BMS, MSD, Merck Serono, Medac, Novartis, Pierre Fabre, Roche, Sanofi, Sun Pharma and Takeda. DS reports grants (or contracts) from (with) Amgen, Array/Pfizer, Bristol-Myers Squibb, MSD, Novartis and Roche; consulting fees from 4SC, Amgen, Array Biopharma, AstraZeneca, Bristol-Myers Squibb, Daiichi Sankyo, Haystick, Immunocore, InFlarX, Innocent, LabCorp, Merck Serono, MSD, Nektar, NeraCare, Novartis, OncoSec, Pfizer, Philogen, Pierre Fabre, Replimune, Roche, Sandoz, Sanofi/Regeneron, Sun Pharma; honoraria from Bristol-Myers Squibb, MSD/Merck, Merck Serono, Novartis, Roche, Sanofi and Sun Pharma; support for attendings meetings or travel support from Bristol-Myers Squibb, MSD, Merck Serono, Novartis, Pierre Fabre and Sanofi; participation on drug safety monitoring or advisory boards for 4SC, Amgen, Array Biopharma, AstraZeneca, Bristol-Myers Squibb, Daiichi Sankyo, Immunocore, InFlarX, Merck Serono, MSD, Nektar, NeraCare, Novartis, OncoSec, Pfizer, Philogen, Pierre Fabre, Replimune, Roche, Sandoz, Sanofi/Regeneron and SunPharma; leadership roles for DeCOG, German Cancer Society, Hiege-Stiftung, Deutsche Hautkrebsstiftung, NVKH e.V. and EuMelaReg. SU declares research support from Bristol Myers Squibb and Merck Serono; speakers and advisory board honoraria from Bristol Myers Squibb, Merck Sharp & Dohme, Merck Serono, Novartis and Roche, and travel support from Bristol Myers Squibb, Merck Sharp & Dohme, and Pierre Fabre. BS is on the advisory board or has received honoraria from Immunocore, Almirall, Pfizer, Sanofi, Novartis, Roche, BMS and MSD, research funding from Novartis and Pierre Fabre Pharmaceuticals, and travel support from Novartis, Roche, Bristol-Myers Squibb and Pierre Fabre Pharma, outside the submitted work.
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