Pembrolizumab monotherapy as first-line therapy in advanced clear cell renal cell carcinoma (accRCC): Results from cohort A of KEYNOTE-427.

4500Background: Programmed death-1 (PD-1) inhibitor–based combination therapy shows clinical benefit in first-line accRCC. However, data are limited on clinical impact of first-line PD-1 inhibitor monotherapy. KEYNOTE-427 (NCT02853344) is a single-arm, open-label, 2-cohort, phase 2 study that evaluates efficacy and safety of the PD-1 inhibitor pembrolizumab (pembro) as first-line monotherapy in accRCC and anccRCC. Results from the accRCC cohort (cohort A) are presented. Methods: Patients (pts) with histologically confirmed accRCC who received no prior systemic therapy were eligible. Additional key eligibility criteria included measurable disease (RECIST v1.1, independent central review [ICR]) and Karnofsky performance status ≥70%. Pembro 200 mg was administered intravenously Q3W for 2 y or until confirmed progressive disease, unacceptable toxicity, or pt decision to withdraw. Primary end point: objective response rate (ORR) per RECIST v1.1, ICR. Additional end points included duration of response, safety,...