e-Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2021

Phase 2 study of cemiplimab in patients with advanced cutaneous squamous cell carcinoma (CSCC): follow-up at 43 months (#321)

Danny Rischin 1 , Nikhil I Khushalani 2 , Chrysalyne D Schmults 3 , Alexander Guminski 4 , Anne Lynn S Chang 5 , Karl D Lewis 6 , Annette M Lim 1 , Leonel Hernandez-Aya 7 , Brett GM Hughes 8 , Dirk Schadendorf 9 , Axel Hauschild 10 , Elizabeth Stankevich 11 , Jocelyn Booth 11 , Suk-Young Yoo 11 , Emmanuel Okoye 11 , Israel Lowy 11 , Matthew G Fury 11 , Michael R Migden 12
  1. Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia
  2. Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida, USA
  3. Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
  4. Department of Medical Oncology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
  5. Department of Dermatology, Stanford University School of Medicine, Redwood City, California, USA
  6. University of Colorado Denver Cancer Center, Aurora, Colorado, USA
  7. Division of Medical Oncology, Department of Medicine, Washington University School of Medicine, St Louis, MO, USA, St Louis, Missouri, USA
  8. Royal Brisbane & Women's Hospital and University of Queensland, Brisbane, Australia
  9. University Hospital Essen, Essen and German Cancer Consortium, Essen, Germany
  10. Schleswig-Holstein University Hospital, Kiel, Germany
  11. Regeneron Pharmaceuticals, Inc., Tarrytown , New York, USA
  12. Departments of Dermatology and Head and Neck Surgery, University of Texas MD Anderson Cancer Center , Houston, Texas, USA

Aim: Primary analysis from pivotal study, NCT02760498, supported the approval of cemiplimab for patients with metastatic CSCC (mCSCC) or locally advanced CSCC (laCSCC) that is not amenable to curative surgery or curative radiation, collectively referred to as advanced CSCC. The 36-month update demonstrated durable responses and emergence of new objective responses, including complete responses. Safety profile was comparable to other anti-PD-1 agents. We present data upto 43 months follow-up.

Methods: Patients received cemiplimab 3 mg/kg Q2W (Group [G]1, mCSCC; G2, laCSCC) or cemiplimab 350 mg Q3W (G3, mCSCC). Primary endpoint was ORR (CR+PR) per ICR.

Results: 193 patients were enrolled (G1: 59; G2: 78; G3: 56). At data cut-off (October 11, 2020), median duration of follow-up (months [range]) for all patients was 15.7 (0.6–43.2); G1: 18.5 (1.1–41.0); G2: 15.5 (0.8–43.2); G3: 17.3 (0.6–38.5). Overall, ORR by ICR (95% CI) improved to 47.2% (39.9–54.4), with no changes for G1 and G2, but an increase in G3 to 46.4% ([33.0–60.3] vs 42.9% [29.7–56.8] since our last update; including two new CR; 19.6%). Median DOR has not been reached (observed DOR range: 1.9–39.4 months). In responding patients, the estimated proportion of ongoing response (95% CI) at 24 months improved to 72.8% (61.2–81.4) vs 69.4%  (55.6–79.6) in our last update. Estimated median Kaplan–Meier PFS (months [95% CI]) for all patients was 18.5 (10.3–31.3); G1: 18.4 (6.8–32.8); G2: 18.5 (11.1–NE); G3: 21.7 (3.6–NE). Median OS by ICR have not been reached. Incidence of immune-related AEs and TEAEs were consistent with previous update. Most common TEAEs by any grade were fatigue (34.7%), diarrhea (27.5%), and nausea (23.8%).

Conclusions: This 43-month follow-up shows incremental improvements in DOR with cemiplimab across all advanced CSCC study groups, and improvements in ORR and complete response rate on the cemiplimab 350 mg Q3W regimen. There were no new safety signals.