First-line pembrolizumab (pembro) monotherapy in advanced clear cell renal cell carcinoma (ccRCC): Updated results for KEYNOTE-427 cohort A.

Abstract

4570 Background: KEYNOTE-427 (NCT02853344) is an open-label, single-arm, phase 2 study to evaluate efficacy and safety of first-line single-agent pembro, a programmed death 1 (PD-1) inhibitor, in patients (pts) with ccRCC (cohort A) and non–clear cell RCC (cohort B). Updated follow up from cohort A are presented. Methods: Pts with histologically confirmed ccRCC, measurable per RECIST v1.1, and no prior systemic therapy were eligible. Pts received pembro 200 mg IV Q3W for 2 y or until confirmed progressive disease, unacceptable toxicity, or pt decision to withdraw. Primary end point was objective response rate (ORR; per RECIST v1.1 blinded independent central review). Additional end points included duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Results: 110 pts enrolled; median (range) follow-up was 18.0 (2.5-22.7) mo. Median age (range) was 64 (29-87); 38.2%, 47.3%, and 14.5% had favorable, intermediate, and poor IMDC risk, respectively; 47.3% were PD-L1 positive. Confirmed ORR was 36.4% with 3 (2.7%) CRs and 37 (33.6%) PRs. Median DOR was not reached. Median PFS was 7.1 mo (95% CI, 5.6-11.0) and median OS was not reached. Results by IMDC category are outlined in the table. By PD-L1 status, confirmed ORR was 44.2% and 29.3% for positive and negative, respectively. By sarcomatoid differentiation (n=11), confirmed ORR was 63.6%. Treatment-related AEs occurred in 80.9%, with pruritus (28.2%) and fatigue (28.2%) most commonly reported. One pt died of treatment-related pneumonitis. Conclusions: With a median 18-months’ follow up, first-line pembro monotherapy continued to show antitumor activity in pts with ccRCC. Meaningful responses were observed in pts with intermediate/poor IMDC risk, PD-L1 positive and sarcomatoid differentiated tumors. Safety profile was comparable to previously reported. Clinical trial information: NCT02853344. [Table: see text]