IMpower133: Patient-reported outcomes (PROs) in a ph1/3 study of first-line (1L) atezolizumab (atezo) + carboplatin + etoposide (CP/ET) in extensive-stage SCLC (ES-SCLC)

Abstract

Background: In IMpower133 (NCT02763579), 1L treatment (tx) with atezo +CP/ET for ES-SCLC provided a significant improvement in survival v placebo (PBO)+ CP/ET and no unexpected safety signals. PROs were assessed to inform the overall tx benefit of adding atezo to CP/ET. Methods: Patients (pts) were randomised to atezo + CP/ET (1200 mg + AUC 5/ 100 mg/m2) (N=201) or PBO + CP/ET (N=202) IV q3w x 12 wks, then maintenance atezo or PBO q3w until progression/intolerable toxicity/clinical benefit loss. Descriptive analyses of EORTC QLQ-C30 and QLQ-LC13 scales (score range 0-100) included change from baseline (BL), cumulative distribution function curves of change at wk 12 and time to deterioration (TTD). A≥10-point change from BL was prespecified as clinically meaningful. Results: Completion rates were≥85% at BL and≥70% to wk 75 in both arms; BL PRO scores were comparable. At wks 27 and 54, 108 and 34 pts remained on study and eligible to complete assessments, respectively. Pts in both arms reported early, notable lung cancer (LC) symptom palliation (Table) with numeric trends of greater improvement with atezo + CP/ET. Higher proportions of atezo + CP/ET pts reported LC symptom relief at wk 12 v PBO + CP/ET. No apparent differences in TTD of cough or chest pain were seen; a numeric delay in TTD of dyspnoea favoured atezo + CP/ET (HR 0.75; 95% CI 0.55-1.02). Atezo + CP/ET pts reported improved physical function above BL until wk 51 and clinically meaningful health-related quality of life (HRQoL) improvements that persisted at most visits through wk 54. Changes in tx-related symptoms (diarrhoea, nausea/vomiting) were similar across arms. (Table Presented) Conclusions: Atezo + CP/ET tx provided a significant improvement in survival as well as immediate and tangible improvements in pt-reported LC symptoms. PROs indicating sustained function and improved HRQoL with minimal impact from tx toxicities further support the positive benefit:risk of atezo +CP/ET in 1L ES-SCLC.