Abstract CT165: Primary analysis of phase 2 results for cemiplimab in patients with metastatic basal cell carcinoma who progressed on or were intolerant to hedgehog inhibitors

Abstract Background: Cemiplimab is the first treatment approved in the US (as cemiplimab-rwlc) for patients with metastatic basal cell carcinoma (mBCC) or locally advanced disease (laBCC) after hedgehog inhibitor (HHI) treatment or for whom an HHI is not appropriate. Cemiplimab provided substantial clinical benefit and an acceptable safety profile in patients with laBCC who discontinued HHI therapy due to progressive disease (PD), intolerance, or no better than stable disease (SD) after 9 months (NCT03132636). Here, we present the primary analysis of the mBCC cohort. Methods: Patients with mBCC (nodal or distant) post-HHI treatment received cemiplimab 350 mg intravenously every 3 weeks for up to 93 weeks or until PD. The primary endpoint was objective response rate (ORR) by independent central review (ICR). Key secondary endpoints included safety and tolerability, ORR per investigator (INV) assessment, duration of response (DOR), progression-free survival (PFS), overall survival (OS), and complete response (CR) rate (data cutoff date: May 20, 2021). Results: Fifty-four patients were enrolled (70.4% male; median age 63.5 years [range, 38−90]; Eastern Cooperative Oncology Group performance status 0 [66.7%] and 1 [33.3%]). Median duration of follow-up was 8.4 months (range 1.5-36.2). ORR per ICR was 24.1% (95% confidence interval [CI], 13.5-37.6); with 1 CR and 12 partial responses (PRs). ORR per INV was 25.9% (95% CI, 15.0-39.7), with 2 CRs and 12 PRs. Among responders, median time to response per ICR was 4.0 months (range, 2.0−10.5). Estimated median DOR per ICR was 16.7 months (95% CI, 9.8-not evaluable). Disease control rate was 63.0% (95% CI, 48.7-75.7) per ICR and 70.4% (95% CI, 56.4-82.0) per INV. Median OS was not reached. Median PFS per ICR was 8.3 months (95% CI, 4.2-15.9). The most common treatment-related adverse events were fatigue (37.0%), diarrhea (14.8%), pruritus (13.0%), hyperthyroidism (9.3%), and arthralgia (9.3%) as well as hypothyroidism, asthenia, constipation, and maculo-papular rash (7.4% each). There were no treatment-related deaths. Conclusions: Cemiplimab provided clinically meaningful antitumor activity, including durable responses, and an acceptable safety profile in patients with mBCC who had progressed on or were intolerant to HHI therapy. Citation Format: Karl Lewis, Ketty Peris, Aleksander Sekulic, Alexander J. Stratigos, Lara Dunn, Zeynep Eroglu, Anne Lynn S. Chang, Michael R. Migden, Suk-Young Yoo, Kosalai Mohan, Ebony Coates, Emmanuel Okoye, Timothy Bowler, Jean-François Baurain, Oliver Bechter, Axel Hauschild, Marcus O. Butler, Leonel Hernandez-Aya, Lisa Licitra, Rogerio I. Neves, Emily S. Ruiz, Frank Seebach, David M. Weinreich, George D. Yancopoulos, Israel Lowy, Priscila Goncalves, Matthew G. Fury. Primary analysis of phase 2 results for cemiplimab in patients with metastatic basal cell carcinoma who progressed on or were intolerant to hedgehog inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT165.