Improved Survival With Adjuvant Atezolizumab vs BSC in Stage IB to IIIA NSCLC

Heather A. Wakelee, MD, FASCO

Long-term data from the IMpower010 trial (NCT02486718) continues to support the use of atezolizumab (Tecentriq) as an adjuvant therapy for patients with resected stage IB to IIIA non–small cell lung cancer (NSCLC). After 5 years of follow-up, the trial presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting demonstrated that atezolizumab continues to show a survival advantage compared with best supportive care (BSC), reinforcing its potential for improving long-term outcomes in this patient population.

The rate of DFS events in the atezolizumab arm was 47.1% vs 52.2% in the BSC arm for patients in the intent-to-treat (ITT) population. Additionally, DFS events in the stage II to IIIA population affected 49.5% and 54.5%, respectively.

In the ITT population, the boundary for DFS was not crossed (stratified HR, 0.85; 95% CI, 0.71-1.01; P = .07). The median DFS was 65.6 months vs 47.8 months in the atezolizumab and BSC arms, respectively. The 3-year DFS rates were 61.4% vs 55.5%, and the 5-year DFS rates were 52.0% and 46.5%.

For the stage II to IIIA population, the stratified DFS HR was 0.83 (95% CI, 0.69-1.00). The median DFS was 57.4 months in the atezolizumab arm and 40.8 months in the BSC arm. At 3 years, the DFS rates were 59.3% and 52.6% while the 5-year DFS rates were 49.3% and 44.4%, respectively.

In the stage II to IIIA PD-L1 tumor cell (TC) of at least 1% population, the median DFS in the atezolizumab arm was 68.5 months vs 37.3 months (HR, 0.70; 95% CI, 0.55-0.91). The DFS rate at 3 years was 62.7% vs 52.1%, and at 5 years, it was 53.2% vs 42.7%.

“The data from this DFS final analysis and second OS interim analysis provide the first phase 3 cancer immunotherapy data in resectable NSCLC with 5 years or more of follow-up and were consistent with the previous reported analyses,” Heather A. Wakelee, MD, FASCO, Winston Chen and Phyllis Huang Professor at Stanford Medicine, deputy director of the Stanford Cancer Institute, and division chief of Medical Oncology, and colleagues wrote in the poster.

This poster reported the DFS final analysis and second OS interim analysis with a minimum follow-up of 60 months. Previous treatment consisted of cisplatin with or without pemetrexed, gemcitabine, docetaxel, or vinorelbine. Patients were given atezolizumab at 1200 mg every 21 days for 16 cycles or 1 year. The primary end point was investigator-assessed DFS, and secondary end points included OS in the ITT population, DFS in the PD-L1 TC of 50% or more and stage II to IIIA disease population, and 3- and 5-year DFS.

The ITT population consisted of 1005 patients, with 507 in the atezolizumab arm and 498 in the BSC arm. The stage II to IIIA population consisted of 882 patients, with 442 in the atezolizumab arm and 440 in the BSC arm. The stage II to IIIA PD-L1 TC of 1% or more population had 476 patients, with 248 in the atezolizumab arm and 228 in the BSC arm.

Patient characteristics were noted to be well-balanced between arms.

In the atezolizumab arm, OS events occurred in 31.4% vs 31.5% in the BSC arm for the ITT population and 32.4% vs 33.0% in the stage II to IIIA population. In either arm in the ITT population, the median OS was not evaluable (NE; HR, 0.97; 95% CI, 0.78-1.22); the same was true for the stage II to IIIA population (HR, 0.94; 95% CI, 0.75-1.19).

For the ITT population, the 3-year OS rates were 79.3% vs 81.1%, and the 5-year rates were 70.9% vs 69.8%. For the stage II to IIIA population, the 3- and 5-year rates were 78.7% vs 79.7% and 69.8% vs 68.6%, respectively.

The median OS for the stage II to IIIA PD-L1 TC of 1% or more population was NE in the atezolizumab arm and 87.1 months in the BSC arm (HR, 0.77; 95% CI, 0.56-1.06). The 3-year OS rates were 82.1% vs 78.9%, and the 5-year OS rates were 74.8% vs 66.3%.

In the stage II to IIIA PD-L1 TC of 50% or more populations, the median DFS in the atezolizumab arm was NE vs 41.1 months in the BSC arm (HR, 0.48; 95% CI, 0.32-0.72). The 3-year DFS rate was 74.9% vs 53.2%, and at 5 years, it was 65.1% vs 44.5%. The median OS was NE in the atezolizumab arm vs 87.1 months in the BSC arm (HR, 0.47; 95% CI, 0.28-0.77). The 3-year OS rates were 89.1% vs 77.8%, and the 5-year rates were 82.7% vs 65.3%.

Efficacy was analyzed for patients with known EGFR/ALK mutations. In the stage II to IIIA PD-L1 of 50% or more population, the median DFS in the atezolizumab arm was NE vs 42.9 months in the BSC arm (HR, 0.49; 95% CI, 0.32-0.75). The 3-year DFS rate was 75.7% vs 55.4%, and the 5-year rate was 66.1% vs 45.8%. The median OS in this subgroup was NE in the atezolizumab arm and 87.1 months in the BSC arm (HR, 0.44; 95% CI, 0.26-0.74). The 3-year OS rate was 89.1% vs 77.5%, and the 5-year OS rate was 82.1% vs 63.7%.

There have been minimal updates regarding safety since the previously reported findings.

In the atezolizumab arm, 31.5% of patients had died vs 31.7% in the BSC arm. Between both arms, patients died due to disease relapse (18.4% vs 23.8%), adverse effects (AEs; 1.8% vs 0.6%), and other reasons (11.3% vs 7.3%).

There were no changes in AEs of special interest in the atezolizumab arm. In the BSC arm, grade 3/4 AEs of special interest occurred in 0.8% of patients, and 0.2% had grade 5 events.

REFERENCE:

Wakelee HA, Altorki NK, Zhou C, et al. Impower010: disease-free survival (DFS) final analysis and secondary overall survival (OS) interim analysis results at ≥5 years follow-up of a phase III study of adjuvant atezolizumab vs best supportive care in resected stage IB-IIIA non-small cell lung cancer. J Clin Oncol. 2024;42(suppl 17):LBA8035. doi:10.1200/JCO.2024.42.17_suppl.LBA8035