Patient-Reported Health-Related Quality of Life in KEYNOTE-604: Pembrolizumab or Placebo Added to Etoposide and Platinum as First-Line Therapy for Extensive-Stage SCLC

Introduction: In the phase 3 KEYNOTE-604 study (NCT03066778), pembrolizumab plus etoposide and platinum chemotherapy (EP) significantly (p = 0.0023) improved progression-free survival versus placebo plus EP in previously untreated extensive-stage SCLC (ES-SCLC). We present health-related quality of life (HRQoL) results from KEYNOTE-604. Methods: Patients with stage IV SCLC were randomized 1:1 to pembrolizumab 200 mg or placebo every 3 weeks for 35 cycles plus four cycles of EP. Secondary end points included mean change from baseline to week 18 in the European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire—Core 30 (QLQ-C30) global health status/quality of life (GHS/QoL) scale and time to deterioration in the composite outcome of cough, chest pain, or dyspnea from QLQ-C30 and QLQ—Lung Cancer Module 13. Two-sided, nominal p values are reported. Results: A total of 439 patients completed at least one QLQ-C30 and QLQ—Lung Cancer Module 13 assessment (pembrolizumab + EP, n = 221; placebo + EP, n = 218). GHS/QoL scores improved from baseline to week 18: least squares mean (95% confidence interval [CI]) changes were 8.7 (5.3–12.1) for pembrolizumab plus EP and 4.2 (0.9–7.5) for placebo plus EP. Between-group differences in least squares mean scores were improved for pembrolizumab plus EP (4.4 [95% CI: 0.2–8.7], p = 0.040]). Median time to deterioration for the composite end point was not reached and 8.7 (95% CI: 5.9–not reached) months, respectively (hazard ratio = 0.80 [95% CI: 0.56–1.14], p = 0.208). Conclusions: First-line pembrolizumab plus EP therapy maintained HRQoL in patients with ES-SCLC and may be associated with greater improvement than placebo plus EP. Together with the efficacy and safety findings in KEYNOTE-604, HRQoL data support the benefit of pembrolizumab in ES-SCLC.