Abstract CT239: IMpower010: Updated overall survival and safety results from Asian patients in a Phase III study of adjuvant atezolizumab vs best supportive care in resected stage IB-IIIA NSCLC
Authors: Wang Jie , Fan Yun , Fang Jian , He Jianxing , Liu Yunpeng , Tao Min , Altorki Nasser , Felip Enriqueta , Wakelee Heather , Vallieres Eric , Belleli Rossella , McNally Virginia , Bennett Elizabeth , Gitlitz Barbara J. , Zhou Caicun 
Published: April 2024

Background The Phase III IMpower010 study (NCT02486718) met its primary endpoint at the disease-free survival (DFS) interim analysis (IA; clinical cutoff: Jan 21, 2021), demonstrating significant DFS improvement with atezolizumab (atezo) vs best supportive care (BSC) after adjuvant chemotherapy (chemo) in patients with resected stage II-IIIA NSCLC, including those with PD-L1 TC ≥1%. Based on these findings, atezo was approved as adjuvant therapy after platinum-based chemo in patients with completely resected PD-L1 TC ≥1% stage II-IIIA NSCLC in the US, China and other countries, and in patients with completely resected PD-L1 TC ≥50% stage II-IIIA NSCLC in the EU and other countries. In a previous exploratory analysis at the time of the DFS IA, the IMpower010 Asian subpopulation showed efficacy and safety outcomes that were consistent with those of the global population (Kenmotsu et al. JSMO 2021). Here we report updated data from the IMpower010 Asian subpopulation at the first overall survival (OS) IA.

Methods The IMpower010 study design and DFS IA have been previously reported (Felip et al. Lancet 2021). Eligible patients with completely resected stage IB (≥4 cm)-IIIA NSCLC (AJCC/UICC v7) received one to four 21-day cycles of cisplatin-based doublet chemo and were subsequently randomized 1:1 to receive atezo 1200 mg q3w (16 cycles) or BSC. The first pre-specified OS IA was conducted at the clinical cutoff date of Apr 18, 2022. OS in the intention-to-treat (ITT) population will be formally tested if DFS in the ITT population reaches statistical significance at the final DFS analysis. Exploratory OS and updated safety outcomes were evaluated in the Asian subpopulation.

Results The Asian ITT population included 233 patients recruited from Japan, mainland China, Taiwan, Korea and Hong Kong. At data cutoff (Apr 18, 2022), the unstratified OS HR was 0.73 (95% CI: 0.28, 1.88) in favor of atezo in the PD-L1 TC ≥1% (SP263) stage II-IIIA population (n=129). The Asian safety-evaluable population included 229 patients (atezo, n=122; BSC, n=107). Any-grade adverse events (AEs) were reported in 95.1% (atezo) and 72.0% (BSC) of safety-evaluable patients; events were Grade 3/4 in 24.6% and 13.1%, respectively. Grade 5 treatment-related AEs occurred in 1 patient in the atezo arm. AEs leading to atezo discontinuation occurred in 21.3% of patients treated with atezo.

Conclusions The IMpower010 Asian subpopulation showed an OS trend favoring atezo vs BSC in the PD-L1 TC ≥1% stage II-IIIA population, as was observed in the global population, although OS data were not formally tested in either population at the first OS IA. With longer follow-up, the safety findings for atezo in the IMpower010 Asian subpopulation remained broadly unchanged, were consistent with those of the global IMpower010 population and were in line with the known safety profile of atezo.

Medical writing support for this abstract was provided by Kia C. E. Walcott, PhD, of Nucleus Global, an Inizio Company, and funded by F. Hoffmann-La Roche, Ltd.

Citation Format: Jie Wang, Yun Fan, Jian Fang, Jianxing He, Yunpeng Liu, Min Tao, Nasser Altorki, Enriqueta Felip, Heather Wakelee, Eric Vallieres, Rossella Belleli, Virginia McNally, Elizabeth Bennett, Barbara J. Gitlitz, Caicun Zhou. IMpower010: Updated overall survival and safety results from Asian patients in a Phase III study of adjuvant atezolizumab vs best supportive care in resected stage IB-IIIA NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT239.