KEYNOTE-629: Phase 2 study of pembrolizumab for recurrent/metastatic or locally advanced unresectable cutaneous squamous cell carcinoma (cSCC).

Abstract

TPS9598 Background: Findings from phase 1 and 2 studies suggest that targeting programmed death 1 (PD-1)/PD-L1 pathway can provide durable antitumor activity in patients with local/regionally advanced or metastatic cSCC and may be a promising treatment option. The open-label, single-arm, phase 2 KEYNOTE-629 trial (NCT03284424) will be conducted to test the clinical activity of the PD-1 inhibitor pembrolizumab in locally advanced, unresectable, and recurrent or metastatic cSCC. Methods: Patients will receive intravenous pembrolizumab 200 mg every 3 weeks for up to 35 infusions (≤24 months) or until protocol-specified treatment discontinuation. Treatment will not be stratified in this study. Eligibility criteria include age ≥18 years; locally advanced cSCC for which the patient is ineligible for resection or radiotherapy (RT) or for which the patient previously underwent RT to the index site or systemic therapy for curative intent; presence of measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1; and Eastern Cooperative Oncology Group performance status 0 or 1. Treatment will be discontinued for progressive disease, unacceptable toxicity, intercurrent illness preventing administration, investigator’s decision, patient withdrawal of consent, pregnancy, or cessation for administrative reasons. Response will be assessed by imaging 6 weeks after treatment initiation, every 6 weeks through year 1, and every 9 weeks thereafter or more frequently if clinically indicated. After disease progression or the start of new anticancer therapy, the patient will be followed up every 12 weeks until death, consent withdrawal, or study end, whichever occurs first. Safety will be monitored throughout the study and for 30 days after treatment end or 90 days if the patient experiences serious adverse events. The primary end point is objective response rate (RECIST v1.1). Secondary end points include response duration, disease control rate, progression-free survival, overall survival, and safety. Recruitment is ongoing in 10 countries and will continue until approximately 50 additional patients with locally advanced, unresectable cSCC are enrolled. Clinical trial information: NCT03284424.