Dr. Chen on the Impact of the Pivotal IMpower133 Trial on SCLC

Hui-Zi Chen, MD, PhD, an assistant professor in the Department of Internal Medicine, Division of Medical Oncology, The Ohio State University Comprehensive Cancer Center—The James, discusses how the phase III IMpower133 trial has helped to propel the field of small-cell lung cancer (SCLC) forward.

The landmark, randomized phase III IMpower133 trial changed the treatment of patients with metastatic SCLC, says Chen. In the study, chemotherapy-naïve patients were treated with the PD-L1 inhibitor atezolizumab (Tecentriq) in combination with standard chemotherapy composed of carboplatin and etoposide compared with placebo, carboplatin, and etoposide. This was followed by a maintenance phase during which patients received either atezolizumab or placebo.

At a median follow-up of 13.9 months, the median overall survival was 12.3 months in the atezolizumab arm versus 10.3 months in the placebo arm (HR, 0.70; 95% CI, 0.54-0.91; P =.007). Although only a 2-month improvement was observed, it was determined to be statistically significant, says Chen. Furthermore, the median progression-free survival with atezolizumab versus the control was 5.2 months and 4.3 months, respectively (HR, 0.77; 95% CI, 0.62- 0.96; P =.02).

The results from the trial lead to the FDA approval of atezolizumab in combination with carboplatin and etoposide for the first-line treatment of patients with extensive-stage SCLC, making it a very important study, concludes Chen.