Abstract 1089P
Background
Retifanlimab is a humanized IgG4 monoclonal antibody targeting human programmed cell death protein (PD)-1. Retifanlimab monotherapy as 500 mg intravenously (IV) every 4 weeks (Q4W) is under investigation in phase II studies in solid tumors. Here we report preliminary clinical activity and safety results from POD1UM-201, a phase II, open-label, single-arm, multicenter study assessing efficacy and safety of retifanlimab in advanced/metastatic MCC.
Methods
Eligible patients (pts) have unresectable locally advanced/metastatic MCC, ECOG PS ≤1, measurable disease per RECIST v1.1, are either chemotherapy (chemo)-naïve or have received ≤3 prior chemo regimens, and have had no prior treatment with anti–PD-1/anti–PD-L1 therapy. The primary endpoint is overall response rate (ORR) per RECIST v1.1 in chemo-naïve pts. Secondary endpoints include safety in all pts, and duration of response (DOR), disease control rate, progression-free survival, and overall survival in chemo-naïve pts.
Results
As of January 8, 2020, 27 pts with MCC had received retifanlimab 500 mg IV Q4W (22 chemo-naïve, 5 refractory, all stage IV). Of the 22 chemo-naïve pts enrolled, 18 have had ≥1 on-study tumor assessment or discontinued. There are 10 (56%) responders (investigator assessed) with 2 (11%) complete responses and 8 (44%) partial responses. Of these, 6 are confirmed and 4 are unconfirmed ongoing responses. Three pts (17%) have stable disease. Among all treated pts (n=27), 16 (59%) had a treatment-emergent adverse event (TEAE); 6 (22%) were ≥Grade 3, 11 (41%) had a treatment-related TEAE (TRAE), 3 (11%) of which were ≥Grade 3. The most common TRAEs were asthenia and pruritus (n=3 each). Seven (26%) had a TEAE of special interest (the only immune-related AE occurring in >1 pt was hypothyroidism [n=2]). Two pts (7%) discontinued treatment due to TEAEs (radiculopathy and polyarthritis). No fatal TEAEs have been reported.
Conclusions
Initial results demonstrate promising activity and safety of retifanlimab in pts with advanced or metastatic chemo-naïve MCC. Updated results from a preplanned analysis for futility will be presented at the meeting.
Clinical trial identification
NCT03599713, July 26, 2018; EudraCT 2018-001627-39, 2018-12-10.
Editorial acknowledgement
Editorial assistance was provided by Matthew Bidgood of Envision Pharma Group (Philadelphia, PA, USA).
Legal entity responsible for the study
Incyte Corporation.
Funding
Incyte Corporation.
Disclosure
G. Grignani: Honoraria (institution), Advisory/Consultancy, Research grant/Funding (institution): Bayer; Honoraria (institution), Advisory/Consultancy: Eisai; Honoraria (institution), Advisory/Consultancy: Lilly; Honoraria (institution), Advisory/Consultancy, Research grant/Funding (institution): Novartis; Honoraria (institution), Advisory/Consultancy: Pfizer; Honoraria (institution), Advisory/Consultancy, Research grant/Funding (institution): PharmaMar; Honoraria (institution): Merck. M. Guida: Advisory/Consultancy: BMS; Advisory/Consultancy: MSD; Advisory/Consultancy: Novartis; Advisory/Consultancy: Pierre Fabre. R. Depenni: Honoraria (institution): BMS; Honoraria (institution): Novartis; Honoraria (institution): MSD F. Spagnolo: Honoraria (institution), Travel/Accommodation/Expenses: BMS; Honoraria (institution): Roche; Honoraria (institution), Advisory/Consultancy, Travel/Accommodation/Expenses: Novartis; Honoraria (institution), Advisory/Consultancy, Travel/Accommodation/Expenses: MSD; Honoraria (institution): Sanofi; Honoraria (institution): Merck; Honoraria (institution): Sunpharma; Honoraria (institution): Pierre-Fabre. F. Spada: Honoraria (institution): EMD Serono; Honoraria (institution), Travel/Accommodation/Expenses: Ipsen; Honoraria (institution), Travel/Accommodation/Expenses: Novartis; Honoraria (institution), Travel/Accommodation/Expenses: Pfizer. F. De Braud: Advisory/Consultancy, Research grant/Funding (institution), Travel/Accommodation/Expenses: Amgen; Advisory/Consultancy, Speaker Bureau/Expert testimony, Research grant/Funding (institution), Travel/Accommodation/Expenses: Bristol-Myers Squibb; Advisory/Consultancy: Celgene; Advisory/Consultancy: Daiichi Sankyo; Advisory/Consultancy: Dompe; Advisory/Consultancy, Research grant/Funding (institution): Ignyta; Advisory/Consultancy, Speaker Bureau/Expert testimony, Research grant/Funding (institution): Novartis; Advisory/Consultancy, Speaker Bureau/Expert testimony: Pfizer; Advisory/Consultancy, Speaker Bureau/Expert testimony: Servier; Advisory/Consultancy: Tiziana Life Sciences; Speaker Bureau/Expert testimony, Research grant/Funding (institution): Lilly; Speaker Bureau/Expert testimony: Menarini; Speaker Bureau/Expert testimony, Research grant/Funding (institution): MSD; Speaker Bureau/Expert testimony, Research grant/Funding (institution), Travel/Accommodation/Expenses: Roche; Research grant/Funding (institution): MedImmune; Research grant/Funding (institution): Merck Serono; Research grant/Funding (institution): Nektar. J. Pulini, S. Shankar, C. Tian: Shareholder/Stockholder/Stock options, Full/Part-time employment: Incyte. C. Lebbé: Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: Amgen; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony, Research grant/Funding (institution), Travel/Accommodation/Expenses: Bristol-Myers Squibb; Honoraria (institution): Incyte; Honoraria (institution), Advisory/Consultancy, Travel/Accommodation/Expenses: MSD; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: Novartis; Honoraria (institution): Pfizer; Honoraria (institution): Pierre-Fabre; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony, Research grant/Funding (institution): Roche; Non-remunerated activity/ies: Avantis Medical Systems. All other authors have declared no conflicts of interest.