75P - Cemiplimab, a human PD-1 monoclonal antibody, in patients (pts) with recurrent or metastatic cervical cancer: Interim data from phase I cohorts

Abstract

Background: For pts who progress after first-line platinum based therapy for recurrent/metastatic cervical cancer, there are no therapies available that have been demonstrated to improve survival or quality of life. Cemiplimab (REGN2810), a human monoclonal antibody to PD-1, exhibited encouraging efficacy and acceptable tolerability in a phase 1 dose escalation study. The present report focuses on interim data from the phase 1 cervical cancer expansion cohorts (ECs) of cemiplimab as a monotherapy (EC 23) or in combination with hypofractionated radiotherapy (hfRT) (EC 24) (NCT02383212). Methods: Pts with recurrent or metastatic cervical cancer resistant to or intolerant of platinum and taxane doublet therapy received cemiplimab 3 mg/kg Q2W IV for up to 48 weeks, in ECs 23 and 24, and hfRT (9 Gy x 3 times/week given 1 week after first dose of cemiplimab) in EC 24. The co-primary objectives were to evaluate the safety, tolerability, and efficacy of cemiplimab monotherapy or in combination with hfRT. Tumour response assessments (in non-irradiated target lesions) were performed by RECIST 1.1 Q8W. Results: As of 1 Sept, 2017, these ECs were fully enrolled with 20 pts (EC 23, n = 10, EC 24, n = 10). Median (range) age was 55.0 (31–76) years (EC 23) and 51.5 (29–65) years (EC 24). ECOG performance status 1 vs. 0 was 60% vs. 40% and 80% vs. 20%, respectively, for EC 23 and EC 24. Investigator-assessed overall response rate (ORR; complete response [CR] + partial response [PR]) was 10.0% (0 CR and 1 PR) in each of EC 23 and EC 24. At the time of data cut-off, both responses were ongoing with durations of 3.7+ months. The most common treatment-emergent adverse events (TEAEs) of any grade were diarrhoea (40.0%), fatigue, hypokalaemia and pain in extremity (each 30.0%) in EC 23, and diarrhoea and urinary tract infection (each 30.0%) in EC 24. There was no grade ≥3 TEAE reported in > 1 patient in either cohort. Conclusions: Cemiplimab as monotherapy and in combination with hfRT demonstrated antitumour activity with an acceptable safety profile in pts with metastatic or recurrent cervical cancer. Cemiplimab monotherapy vs. chemotherapy in ≥ 2nd line cervical cancer is currently being evaluated in a global randomised phase 3 study (NCT03257267). Editorial acknowledgement: Medical writing support under the direction of the authors was provided by Emmanuel Ogunnowo, PhD, of Prime (Knutsford, UK) and funded by Regeneron Pharmaceuticals, Inc. and Sanofi according to Good Publication Practice guidelines. Clinical trial identification: NCT02383212. Legal entity responsible for the study: Regeneron Pharmaceutical Inc. and Sanofi. Funding: Regeneron Pharmaceutical Inc. and Sanofi. Disclosure: D. Rischin: Research funding: Genentech/Roche, Merck, Amgen, Regeneron, Bristol-Myers Squibb. A. González-Martin: Consulting, advisory, speakers’ bureau, travel accommodation expenses: AstraZeneca, Tesaro, Roche, Pharmamar. J.Y. Hou: Consultant and fees: Foundation Medicine, Massive Bio, Inc. D. Cho: Consulting fees: Pfizer, BMS, Exelixis, Genentech, Prometheus. G. Falchook: Funding for trial for submitted work. S. Jabbour: Research funding grants: Merck, Nestle outside of the submitted work. K. Moore: KInstitutional consultancy (honorarium and ad board) fees: Tesaro, Genentech Roche, Clovis, AstraZeneca (for agents not involved in the SOLO-1 study), Immunogen, VBL Therapeutics, Janssen. M.G. Fury: Employee and shareholder: Regeneron Pharmaceuticals, Inc.; Patents, royalties, other intellectual property: Regeneron Pharmaceuticals, Inc. M. Feng: Employee and shareholder: Regeneron Pharmaceuticals, Inc., Bayer. J. Li: Employee and shareholder: Regeneron Pharmaceuticals, Inc., Novartis. I. Lowy: Employee, shareholder, fees for travel and accommodation expenses, leadership: Regeneron Pharmaceuticals, Inc. M. Mathias: Employee and shareholder: Regeneron Pharmaceuticals, Inc. All other authors have declared no conflicts of interest.