KEYNOTE-048: Progression after the next line of therapy following pembrolizumab (P) or P plus chemotherapy (P+C) vs EXTREME (E) as first-line (1L) therapy for recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC).
Kevin J. Harrington, Danny Rischin, Richard Greil, Denis Soulières, Makoto Tahara, Gilberto de Castro, Amanda Psyrri, Neus Basté, Prakash Neupane, Åse Bratland, Thorsten Fuereder, Brett Hughes, Ricard Mesı́a, Nuttapong Ngamphaiboon, Tamara Rordorf, Wan Zamaniah Wan Ishak, Yayan Zhang, Burak Gümüşçü, Ramona F. Swaby, Barbara Burtness
Abstract
6505 Background: 1L P vs E improved OS in PD-L1 CPS ≥20 and CPS ≥1 populations, and led to noninferior OS in the total population, with favorable safety; 1L P+C vs E had superior OS in CPS ≥20, CPS ≥1, and total populations with comparable safety in the phase 3 KEYNOTE-048 study (NCT02358031) in patients with R/M HNSCC. Neither P vs E nor P+C vs E improved PFS in the PD-L1 CPS ≥20, CPS ≥1, or total populations. Here, we present the progression after the next line of therapy (PFS2) to assess the effect of 1L P or P+C and subsequent anticancer therapy on patient outcomes. Methods: Patients with locally incurable R/M HNSCC and no prior systemic therapy in the R/M setting were randomly assigned 1:1:1 to P, P+C, or E. PFS2 was defined as time from randomization to objective tumor progression on next-line therapy or death from any cause. PFS2 was estimated using the Kaplan-Meier method as an exploratory outcome confined to those receiving subsequent therapy after 1L P. HR and 95% CIs were based on a Cox regression model with Efron’s method of tie handling with treatment as a covariate (stratified by ECOG performance status [PS], HPV status, and PD-L1 for CPS ≥1 and total populations; by ECOG PS and HPV status for CPS ≥20 population). Data cutoff: Feb 25, 2019. Results: Of 882 (301 [P]; 281 [P+C]; 300 [E]) treated patients,422 (P: 148 [49.2%]; P+C: 115 [40.9%]; E: 159 [53.0%]) received subsequent anticancer therapy after 1L P, most commonly C (P: 135 [44.9%]; P+C: 88 [31.3%]; E: 102 [34.0%]); EGFR inhibitor (P: 59 [19.6%]; P+C: 37 [13.2%]; E: 19 [6.3%]); and immune checkpoint inhibitor (P: 6 [2.0%]; P+C: 12 [4.3%]; E: 50 [16.7%]); patients may have received more than one type of subsequent therapy. Median PFS2 is reported in Table. Conclusions: In patients with R/M HNSCC, longer median PFS2 was observed in the CPS ≥20 and CPS ≥1 populations for P vs E, and in the CPS ≥20, CPS ≥1, and total populations for P+C vs E. These data further support use of 1L P or P+C in patients with R/M HNSCC. Clinical trial information: NCT02358031 . [Table: see text]