SITC 2019: Atezolizumab Monotherapy Versus Chemotherapy in PD-L1–Selected Lung Cancer
Posted: Wednesday, November 20, 2019
There appears to be significant improvement in overall survival when patients with non–small cell lung cancer (NSCLC) who have expression of PD-L1 are treated with the anti–PD-L1 antibody atezolizumab, rather than platinum-based chemotherapy in the first-line setting, based on the interim overall survival analysis of the phase III IMpower110 trial. Giuseppe Giaccone, MD, PhD, of Georgetown University in Washington, DC, and colleagues presented their findings at the 2019 Society for Immunotherapy of Cancer (SITC) Annual Meeting in National Harbor, Maryland (Abstract O81).
The team enrolled 572 patients who had not yet been treated for stage IV nonsquamous or squamous NSCLC. All patients had expression of PD-L1 on over 1% of tumor cells (TC) or tumor-infiltrating immune cells (IC). PD-L1 expression was expressed as the percentage of PD-1–expressing tumor cells (TC3 ≥ 50%, TC2 ≥ 5% and < 50%, TC1 ≥ 1% and < 5%, and TC0 < 1%) and PD-L1–expressing tumor-infiltrating immune cells as the percentage of tumor area (IC3 ≥ 10%, IC2 ≥ 5% and < 10%, IC1 ≥ 1% and < 5%, and IC0 < 1%). Patients were randomly assigned to receive 1,200 mg of intravenous atezolizumab or platinum-based chemotherapy.
The efficacy populations included TC1/2/3 or IC1/2/3 wild-type patients (n = 554), TC2/3 or IC2/3 wild-type patients (n = 328), and wild-type TC3 or IC3 patients (n = 205). The median follow-up was 15.7 months in the TC3 or IC3 wild-type patients; in this population, atezolizumab monotherapy improved overall survival by 7.1 months compared with chemotherapy (hazard ratio = 0.595).
Treatment-related adverse events occurred in 60.5% of patients on the atezolizumab regimen and 85.2% of patients receiving chemotherapy. Grade 3 or 4 adverse events occurred in 12.9% of patients in the atezolizumab group and 44.1% of the chemotherapy group.
Disclosure: For full disclosures of other study authors, visit sitcancer.org.