There was a doubling of the 12-month progression-free survival rate, from 12.0% to 24.7%, Dr. Jotte reported.
Atezolizumab improved progression-free survival across levels of PD-L1 expression, but benefit was most pronounced in patients with tumors having a high level of this biomarker (hazard ratio, 0.44).
Findings were similar for response, with a higher overall response rate seen with atezolizumab plus chemotherapy versus chemotherapy alone (49% vs. 41%) and greatest difference in the subgroup whose tumors were highly PD-L1 positive (60% vs. 33%). Median duration of response was 7.2 months with the immunotherapy and 5.2 months without it.
Interim overall survival results showed that patients lived a median of 14.0 months with atezolizumab plus chemotherapy and 13.9 months with chemotherapy alone (hazard ratio, 0.96; P = .6931).