Findings from a recent study demonstrate that adding 1L atezolizumab to standard carboplatin and etoposide prolonged overall survival (OS) and progression-free survival (PFS) in patients with extensive-stage small cell lung cancer (ES-SCLC), as compared to carboplatin and etoposide treatment alone.

Stephen V. Liu, M.D., associate professor of medicine at Georgetown University and a member of the trial steering committee, presented these findings today at the International Association for the Study of Lung Cancer’s (IASLC’s) 19th World Conference on Lung Cancer (WCLC) in Toronto, Canada.

IMpower133, a global Ph1/3, double-blind, randomized, placebo-controlled trial, evaluated the efficacy and safety of 1L atezolizumab as adjunctive therapy to the standard-of-care, combination carboplatin and etoposide, in 403 treatment-naïve patients with ES-SCLC.

Enrolled participants were randomized 1:1 to receive four 21-day cycles of carboplatin and etoposide with either atezolizumab, a humanized monoclonal anti–PD-L1 antibody, or placebo.

Treatment was followed by maintenance therapy with atezolizumab or placebo until toxicity was intolerable or there was evidence of progressive disease, as defined by the Response Evaluation Criteria in Solid Tumors (RECIST) or loss of clinical benefit.

The study successfully met its co-primary endpoints of OS and investigator-assessed PFS. Incidence of adverse events were reported and graded according to the National Cancer Institutes’ fourth version of the Common Terminology Criteria for Adverse Events.

No new safety signals were identified, and the types and incidence of immune related adverse events was similar to that seen with atezolizumab monotherapy.

“The standard of care for extensive-stage small cell lung cancer has been unchanged for decades, which has contributed to unacceptably poor outcomes,” said Dr. Liu. “This is the first study in 30 years to show a significant improvement in survival in the first line treatment of this highly lethal disease. This is an exciting time in oncology, and we are thrilled to finally see real progress in the SCLC space.”

Source: IASLC