Pembrolizumab demonstrated clinically meaningful and durable antitumor activity with a manageable safety profile in recurrent/metastatic (R/M) cutaneous squamous cell carcinoma (cSCC).
KEYNOTE-629 was a global, open-label, nonrandomized, phase 2 trial of patients with locally advanced (LA) or R/M cSCC conducted at 59 centers. Eligible patients received intravenous pembrolizumab 200 mg every three weeks for up to 35 cycles. Primary endpoint was objective response rate (ORR), defined as the percentage of patients with a complete or partial response, by blinded independent central review per Response Evaluation Criteria in Solid Tumors 1.1. Secondary endpoints included duration of response (DOR), disease control rate, progression-free survival, overall survival, and safety and tolerability. Efficacy and safety were analyzed in patients who were treated with at least one dose of pembrolizumab.
Between Nov 29, 2017, and Sep 25, 2019, 159 patients were enrolled and treated with pembrolizumab (LA cohort, N=54; R/M cohort, N=105). The median time from the first dose to data cutoff (July 29, 2020) was 14.9 (IQR, 12.6-17.2) months for the LA cohort and 27.2 (IQR, 25.6-29.2) months for the R/M cohort. In the LA cohort, ORR was 50.0% (95% CI, 36.1%-63.9%), including 16.7% patients with a complete response and 33.3% with a partial response. In the R/M cohort, ORR was 35.2% (95% CI, 26.2%-45.2%), including 10.5% patients with a complete response and 24.8% with a PR. Median DOR was not reached in either cohort. Grade 3-5 treatment-related adverse events occurred in 11.9% of patients.
The robust antitumor activity of pembrolizumab in both LA and R/M cSCC was confirmed and demonstrated to be durable without unexpected safety signals. Our findings establish pembrolizumab as a promising treatment option for cutaneous squamous cell carcinoma.
ClinicalTrials.gov: NCT03284424.

Copyright © 2021. Published by Elsevier Ltd.

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