Adjuvant atezolizumab in Japanese patients with resected stage IB-IIIA non-small cell lung cancer (IMpower010)

Abstract

The global phase 3 IMpower010 study evaluated adjuvant atezolizumab versus best supportive care (BSC) following platinum-based chemotherapy in patients with resected stage IB–IIIA non-small cell lung cancer (NSCLC). Here, we report a subgroup analysis in patients enrolled in Japan. Eligible patients had complete resection of histologically or cytologically confirmed stage IB (tumors ≥4 cm)–IIIA NSCLC. Upon completing 1–4 cycles of adjuvant cisplatin-based chemotherapy, patients were randomized 1:1 to receive atezolizumab (fixed dose of 1200 mg every 21 days; 16 cycles or 1 year) or BSC. The primary endpoint of the global IMpower010 study was investigator-assessed disease-free survival, tested hierarchically first in patients with stage II–IIIA NSCLC whose tumors expressed programmed death-ligand 1 (PD-L1) on ≥1% of tumor cells, then in all randomized patients with stage II–IIIA NSCLC, and finally in the intention-to-treat (ITT) population (stage IB–IIIA NSCLC). Safety was evaluated in all patients who received atezolizumab or BSC. The study comprised 149 enrolled patients in three populations: ITT (n = 117; atezolizumab, n = 59; BSC, n = 58), all-randomized stage II–IIIA (n = 113; atezolizumab, n = 56; BSC, n = 57), and PD-L1 tumor cells ≥1% stage II–IIIA (n = 74; atezolizumab, n = 41; BSC, n = 33). At the data cutoff date (January 21, 2021), a trend toward disease-free survival improvement with atezolizumab vs BSC was observed in the PD-L1 tumor cells ≥1% stage II–IIIA (unstratified hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.25–1.08), all-randomized stage II–IIIA (unstratified HR, 0.62; 95% CI, 0.35–1.11), and ITT (unstratified HR, 0.61; 95% CI, 0.34–1.10) populations. Atezolizumab-related grade 3/4 adverse events occurred in 16% of patients; no treatment-related grade 5 events occurred. Adjuvant atezolizumab showed disease-free survival improvement and a tolerable toxicity profile in Japanese patients in IMpower010, consistent with the global study results.