Atezolizumab Versus Docetaxel in Pretreated Patients With NSCLC: Final Results From the Randomized Phase 2 POPLAR and Phase 3 OAK Clinical Trials

Abstract

Introduction: The phase 2 POPLAR and phase 3 OAK studies of the anti-programmed death-ligand 1 (PD-L1) immunotherapy atezolizumab in patients with previously treated advanced NSCLC revealed significant improvements in survival versus docetaxel (p = 0.04 and 0.0003, respectively). Longer follow-up permits evaluation of continued benefit of atezolizumab. This study reports the final overall survival (OS) and safety findings from both trials.

Methods: POPLAR randomized 287 patients (atezolizumab, 144; docetaxel, 143) and OAK randomized 1225 patients (atezolizumab, 613; docetaxel, 612). The patients received atezolizumab (1200 mg fixed dose) or docetaxel (75 mg/m²) every 3 weeks. Efficacy and safety outcomes were evaluated.

Results: A longer OS was observed in patients receiving atezolizumab versus docetaxel in POPLAR (median OS = 12.6 mo versus 9.7 mo; hazard ratio = 0.76, 95% confidence interval [CI]: 0.58-1.00) and OAK (median OS = 13.3 versus 9.8 mo; hazard ratio = 0.78, 95% CI: 0.68-0.89). The 4-year OS rates in POPLAR were 14.8% (8.7-20.8) and 8.1% (3.2-13.0) and those in OAK were 15.5% (12.4-18.7) and 8.7% (6.2-11.3) for atezolizumab and docetaxel, respectively. Atezolizumab had improved OS benefit compared with docetaxel across all PD-L1 expression and histology groups. Most 4-year survivors in the docetaxel arms received subsequent immunotherapy (POPLAR, 50%; OAK, 65%). Of the 4-year survivors, most had Eastern Cooperative Oncology Group performance status of 0 and nonsquamous histological classification and approximately half were responders (POPLAR: atezolizumab, seven of 15; docetaxel, three of four; OAK: atezolizumab, 24 of 43; docetaxel, 11 of 26). Treatment-related grade 3/4 adverse events occurred in 27% and 16% of atezolizumab 4-year survivors in POPLAR and OAK, respectively.

Conclusions: Long-term follow-up suggests a consistent survival benefit with atezolizumab versus docetaxel in patients with previously treated NSCLC regardless of PD-L1 expression, histology, or subsequent immunotherapy. Atezolizumab had no new safety signals, and the safety profile was similar to that in previous studies.

Keywords: Atezolizumab; Docetaxel; Non–small cell lung cancer; Overall survival.