Association of antibiotic treatment with survival outcomes in treatment-naïve melanoma patients receiving immune checkpoint blockade.

Purpose: The interaction of gut microbiome and immune system is being studied with increasing interest. Disturbing factors, such as antibiotics may impact the immune system via gut and interfere with tumor response to immune checkpoint blockade (ICB).
Methods: In this multicenter retrospective cohort study exclusively treatment-naïve patients with cutaneous or mucosal melanoma treated with first-line anti-PD-1 based ICB for advanced, non-resectable disease between 06/2013 and 09/2018 were included. Progression-free (PFS), and overall survival (OS) according to antibiotic exposure (within 60 days prior to ICB and after the start of ICB vs. no antibiotic exposure) were analyzed. To account for immortal time bias, data from patients with antibiotics during ICB were analyzed separately in the time periods before and after start of antibiotics.
Results: Among 578 patients with first-line anti-PD1 based ICB, 7% of patients received antibiotics within 60 days prior to ICB and 19% after starting ICB. Antibiotic exposure prior to ICB was associated with worse PFS (adjusted HR 1.75 [95% CI 1.22-2.52]) and OS (adjusted HR 1.64 [95% CI 1.04-2.58]) by multivariate analysis adjusting for potential confounders. The use of antibiotics after the start of ICB had no effect on either PFS (adjusted HR 1.19; 95% CI 0.89-1.60) or OS (adjusted HR 1.08; 95% CI 0.75-1.57).
Conclusions: Antibiotic exposure within 60 days prior to ICB seems to be associated with worse PFS and OS in melanoma patients receiving first-line anti-PD1 based therapy, whereas antibiotics after the start of ICB do not appear to affect PFS or OS.
Competing Interests: Declaration of Competing Interest E.C. received travel support from Bristol-Myers Squibb, Merck Sharp & Dohme, Novartis, UCB and Almirall outside the submitted work. B.S. Honoraria from MSD, BMS, SUN Pharma, Allmiral, Novartis; Advisory Board for MSD, BMS, Pierre Fabre Pharma, Sanofi; travel support from BMS, Novartis, Pierre Fabre Pharma; Research Funding from Novartis; all outside the submitted work. M.S. received speaker honoraria from Novartis and advisory board honoraria from Sanofi Genzyme. R.G. declares research support from Novartis, Amgen, Sanofi, Merck-Serono, Admiral, SUN Pharma and Kyowa-Kirin; honoraria for lectures from Roche Pharma, Bristol-Myers Scuibb, Novartis, MSD. Almirall, Amgen, Merck-Serono, SUN Pharma, Pierre-Fabre, and Sanofi; advisory honoraria from Roche Pharma, Bristol-Myers Squibb, Novartis, MSD, Admiral, Amgen, Pierre-Fabre, Merck-Serono, 4SC, Sun Pharma, Merck-Serono, Sanofi, Delcath and Immunocore. C.L. receives personal fees and travel reimbursement from MSD, BMS, Merck, Sanofi, Almirall Hermal, Kyowa Kirin, Biontech, Pierre Fabre, Novartis and Sun Pharma outside the submitted work. K.K. has served as consultant or/and has received honoraria from Amgen, Roche, Bristol Myers Squibb, Merck Sharp and Dohme, Pierre Fabre and Novartis, and received travel support from Amgen, Merck Sharp and Dohme, Bristol Myers Squibb, Amgen, Pierre Fabre, Medac and Novartis. A.Z.M. received travel support from Novartis, Genzyme, and Bristol-Myers Squibb, outside the submitted work. J.M.P. served as consultant and/or has received honoraria from Bristol-Myers Squibb, Novartis, Sanofi and received travel support from Bristol-Myers Squibb, Novartis, Pierre Fabre and Therakos. E.G. received travel support from Pierre-Fabre, outside the submitted work. A.M. received travel support from Novartis, outside the submitted work. A.R. received grants, personal fees, and non-financial support from Novartis; grants and non-financial support from Bristol-Myers Squibb; personal fees and non-financial support from Roche; personal fees from Merck Sharp & Dohme; and non-financial support from Amgen, outside the submitted work. S.U. declares research support from Bristol Myers Squibb and Merck Serono; speakers and advisory board honoraria from Bristol Myers Squibb, Merck Sharp & Dohme, Merck Serono, and Novartis; and meeting and travel support from Almirall, Bristol-Myers Squibb, IGEA Clinical Biophysics, Merck Sharp & Dohme, Novartis, Pierre Fabre, and Sun Pharma; outside the submitted work. D.S. received grants and other support from Bristol-Myers Squibb, personal fees from Bristol-Myers Squibb during the conduct of the study; personal fees from Amgen; personal fees from Boehringer Ingelheim; personal fees from InFlarX; personal fees and other support from Roche; grants, personal fees and other support from Novartis; personal fees from Incyte; personal fees and other support from Regeneron; personal fees from 4SC; personal fees from Sanofi; personal fees from Neracare; personal fees from Pierre-Fabre; personal fees and other support from Merck-EMD; personal fees from Pfizer; personal fees and other support from Philiogen; personal fees from Array, personal fees and other support from MSD Sharp & Dohme, outside the submitted work. E.L. served as consultant and/or has received honoraria from Bristol-Myers Squibb, Merck Sharp & Dohme, Novartis, Pierre-Fabre, Sanofi, Sunpharma, Takeda and travel support from Bristol-Myers Squibb, Pierre- Fabre, Sunpharma and Novartis, outside the submitted work.A.S. L.Z. served as consultant and/or has received honoraria from Roche, Bristol-Myers Squibb, Merck Sharp & Dohme, Novartis, Pierre-Fabre, and Sanofi; and travel support from Merck Sharp & Dohme, Bristol-Myers Squibb, Amgen, Pierre-Fabre, and Novartis, outside the submitted work. All remaining authors have declared no conflicts of interest.
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