Atezolizumab Demonstrates Positive Disease-free Survival Benefit Among Patients With NSCLC

Researchers of a recent study examined best supportive care compared with adjuvant atezolizumab (atezo; anti—PD-L1) in patients with early-stage resected non-small cell lung cancer (NSCLC) and observed positive disease-free survival (DFS) benefit after adjuvant chemotherapy.

Per the researchers’ background data, “Adjuvant platinum-based chemotherapy provides only a modest 5-year survival benefit in fully resected, high-risk early-stage NSCLC.”

A preplanned interim analysis of Impower010— a randomized phase 3 open-label trial of adjuvant atezolizumab vs best supportive care—was conducted for eligible patients.

Eligible participants had completely resected (4-12 weeks prior to enrollment) Stage IB (≥4 cm)-IIIA NSCLC (AJCC/UICC v7) and ECOG PS 0-1. Of the 1280 patients enrolled in the trial, 1269 received up to 4 21-day cycles of cisplatin-based chemotherapy (plus pemetrexed, docetaxel, gemcitabine, or vinorelbine). Of the 1269 patients selected, 1005 were then randomized one-to-one for 16 cycles of 1200 mg atezolizumab once every three weeks or received best supportive care.

The researchers assessed DFS and overall survival hierarchically: “first DFS in the PD-L1 TC ≥1% (SP263) subgroup with Stage II-IIIA disease, then DFS in all randomized patients with Stage II-IIIA disease, then DFS in the ITT population (Stage IB-IIIA) and finally OS in the ITT population.”

Efficacy was measured based on randomized patients and safety was observed in patients who received ≥1 dose of atezolizumab or who had ≥1 post-baseline safety assessment if randomized to the best supportive care arm.

According to the results of the analysis, after a median follow-up of 32.2 months in the ITT population, atezolizumab demonstrated significant DFS benefit compared with best supportive care “in the PD-L1 TC ≥1% Stage II-IIIA and all randomized Stage II-IIIA populations; the significance boundary was not crossed for DFS in the ITT population.”

Overall survival data was designated too immature and not formally tested to produce results.

For the patient arm who received atezolizumab, patients received a median of 16 doses.

Any grade adverse events were reported in 92.7% of the atezolizumab arm, compared with 70.7% in the best supportive care arm. A reported 21.8% and 11.5% of adverse events were grade 3 and 4, respectively. Grade 5 adverse events were recorded for 0.8% of patients in the atezolizumab arm. Discontinuation of atezolizumab occurred in 18.2% of patients.

Overall, researchers reported that Impower010 met its primary endpoint, showing DFS benefit with adjuvant atezolizumab vs best supportive care after adjuvant chemotherapy in patients with resected Stage II-IIIA NSCLC, with pronounced benefit in the PD-L1 TC ≥1% subgroup.”

Further, “The safety profile of atezolizumab was consistent with prior experience of atezolizumab monotherapy across indications and lines of therapy,” concluded researchers.

Atezolizumab was approved by the US Food & Drug Administration on May 18, 2020 for the first-line treatment of adult patients with metastatic NSCLC whose tumors have high PD-L1 expression (PD-L1 stained ≥ 50% of tumor cells [TC ≥ 50%] or PD-L1 stained tumor-infiltrating immune cells [IC] covering ≥ 10% of the tumor area [IC ≥ 10%]), with no EGFR or ALK genomic tumor aberrations.

Reference:

1. Wakelee HA, Altorki NK, ZhouI C, et al. Mpower010: 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). doi:10.1200/JCO.2021.39.15_suppl.8500 Journal of Clinical Oncology 39, no. 15_suppl (May 20, 2021) 8500-8500.
2. US Food & Drug Administration. FDA approves atezolizumab for first-line treatment of metastatic NSCLC with high PD-L1 expression. Published May 18, 2020. Accessed October 1, 2021. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-atezolizumab-first-line-treatment-metastatic-nsclc-high-pd-l1-expression