IMpower010: Atezolizumab versus Best Supportive Care Post-Adjuvant Chemotherapy in Resected NSCLC

High-risk, early-stage patients with fully resected non–small-cell lung cancer (NSCLC) experience only a modest 5-year survival benefit from adjuvant platinum-based chemotherapy (4%-5% improvement in overall survival [OS] at 5 years vs observation). Disease-free survival (DFS) results from the preplanned interim analysis of IMpower010, a randomized, phase 3, open-label trial of adjuvant atezolizumab (anti–PD-L1) compared with best supportive care (BSC) after adjuvant chemotherapy in patients with early-stage resected NSCLC, were presented at ASCO 2021.1

IMpower010 enrolled patients who had undergone complete resection (4-12 weeks prior to enrollment), stage IB (≥4 cm) to stage IIIA NSCLC (based on AJCC/UICC v7), and Eastern Cooperative Oncology Group performance status 0 or 1. Of the patients who were enrolled (n = 1280), 1269 received up to four 21-day cycles of adjuvant cisplatin-based chemotherapy (plus pemetrexed, docetaxel, gemcitabine, or vinorelbine). Most of these patients (n = 1005 of 1269) were subsequently randomized to either 16 cycles of atezolizumab 1200 mg every 3 weeks or BSC.1

The primary end point was investigator-assessed DFS, and a key secondary end point was OS, with efficacy assessments based on randomized patients. Safety was assessed in the safety-evaluable population, which were patients who received at least 1 dose of atezolizumab or who had at least 1 post-baseline safety assessment if randomized to the BSC arm.1

Median follow-up was 32.8 months in the intent-to-treat (ITT) population at data cutoff.1 Baseline characteristics were generally balanced between arms.1 Statistically significant DFS benefit was seen in patients treated with atezolizumab compared with BSC in the PD-L1 tumor cells ≥1% stage II to IIIA group (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.50-0.88; P = .004) and in all randomized stage II to IIIA patients (HR, 0.79; 95% CI, 0.64-0.96; P = .02).1 The significance boundary was not crossed for DFS in the ITT population (stage IB-IIIA). OS data were immature and not formally tested, but a trend toward improvement in OS in patients treated with atezolizumab was seen in the PD-L1 ≥1% stage II-IIIA group.1

Any-grade adverse events (AEs) occurred in 92.7% (atezolizumab) and 70.7% (BSC) of patients with grade 3/4 AEs in 21.8% and 11.5%, respectively.1 In the atezolizumab arm, AEs resulting in treatment discontinuation occurred in 18.2% of patients, and grade 5 treatment-related AEs occurred in 0.8% of patients.1

IMpower010 met its primary end point; atezolizumab after adjuvant platinum-based chemotherapy showed a DFS benefit compared with BSC in patients with resected stage II to IIIA NSCLC. The DFS benefit was particularly pronounced in the PD-L1 tumor cells ≥1% subgroup. Atezolizumab-related toxicities were consistent with prior experience across indications and lines of therapy.1

Reference

  1. Wakelee HA, Altorki NK, Zhou C, et al. IMpower010: primary results of a phase III global study of atezolizumab versus best supportive care after adjuvant chemotherapy in resected stage IB-IIIA non-small cell lung cancer (NSCLC). American Society of Clinical Oncology (ASCO), June 2021; Abstract 8500.

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