First-line atezolizumab plus chemotherapy in extensive-stage small-cell lung cancer

The IMpower133 clinical trial investigated whether adding a checkpoint inhibitor of programmed death signaling might improve the benefits of chemotherapy in patients with late-stage small-cell lung cancer. The Phase III study involved about 400 treatment-naive patients who were randomly allocated to one of two treatment groups.

The IMpower133 clinical trial investigated whether adding a checkpoint inhibitor of programmed death signaling might improve the benefits of chemotherapy in patients with late-stage small-cell lung cancer. The Phase III study involved about 400 treatment-naive patients who were randomly allocated to one of two treatment groups. All underwent chemotherapy with carboplatin and etoposide, but one-half also received atezolizumab. The other patients received placebo. Treatment was administered during an induction phase consisting of four 21-day cycles and an ensuing maintenance phase that ended when the patient experienced unacceptable toxic effects or disease progression, or when the therapy ceased to provide clinical benefit. Followup took place after a median 13.9 months, at which time overall survival was measured at a median 12.3 months in the atezolizumab group compared with 10.3 months in the control group. Median progression-free survival, meanwhile, was 5.2 months vs. 4.3 months, respectively. The evidence supports the addition of atezolizumab to chemotherapy as a first-line therapy for extensive-stage small-cell lung cancer, the researchers concluded.