Encouraging Results Seen With PD-L1 Inhibitor in Early-Stage NSCLC

CHICAGO–An interim efficacy analysis of a large, multicenter clinical trial showed encouraging news in the neoadjuvant treatment of early-stage non–small-cell lung cancer (NSCLC) with the programmed death ligand 1 (PD-L1) inhibitor atezolizumab (abstract 8503). Researchers presented preliminary safety and efficacy data at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting, held May 31–June 4 in Chicago.

The study is planned to include 180 patients with stages IB to selected IIIB resectable NSCLC. The interim analysis included the first 101 patients (47 males; median age, 65 years). All included patients were Eastern Cooperative Oncology Group performance status 0 to 1, 23% were current smokers, and 68% were former smokers. A total of 65% had non-squamous NSCLC; 11% of patients were stage IB, 16% IIA, 28% IIB, 39% IIIA, and 7% IIIB.

Two treatment-unrelated grade 5 adverse events occurred. Treatment-related adverse events included fatigue (20%), infusion-related reaction (11%), and pyrexia (10%). In addition, 6% of patients experienced treatment-related grade 3 to 4 adverse events.

Among 77 patients eligible for the primary efficacy analysis, the major pathologic response rate (MPR), defined as 10% or less of tumor cells being viable at resection, was 19% (95% CI, 11–30%). In total, 5% of patients experienced a pathological complete response, and 49% had a 50% or greater pathologic regression. 

Biomarker analyses revealed that pathological response and MPR occurred regardless of PD-L1 expression. There was no association between tumor mutational burden and MPR or pathological regression. There was also no association between gene alterations and MPR.

“Pathological complete response and major pathologic response rates were encouraging in this large multicenter trial,” said David Kwiatkowski, MD, PhD, professor of medicine at Harvard Medical School, during his presentation of the results.

The authors concluded, “Efficacy interim analysis passed its futility boundary, and study enrollment continues. Safety, efficacy results and ongoing correlative analyses will be presented.”

Discussant Maximilian Diehn, MD, PhD, associate professor at Stanford, called for more research into biomarkers in this patient population. He noted that the LCMC3 study found no correlation of MPR with tumor mutation burden, but other studies have found a link, and the differences may be down to a lack of consensus on how to best make that determination. “I think more work is needed to evaluate this biomarker,” said Diehn.