As noted before, the primary endpoint of overall survival among all patients with a TPS of 1% or greater was met, with respective median overall survival in the pembrolizumab vs. chemotherapy groups of 16.7 vs. 12.1 months, translating into a hazard ratio favoring pembrolizumab of 0.81 (P = .0018). Respective hazard ratios for the TPS 20% or greater and TPS 50% or greater groups were 0.77 (P = .0020), and 0.69 (P = .0003).
At 12.8 months of median follow-up, 13% of patients assigned to pembrolizumab were still on the drug, and 4.3% of patients were receiving maintenance pemetrexed.
Treatment-related adverse events of any grade occurred in 399 of 636 patients assigned to pembrolizumab (62.7%), vs. 553 of 615 patients assigned to chemotherapy (89.9%).
Grade 3 or greater events occurred in 17.8% vs. 41% of patients, respectively, There were 13 deaths related to therapy in the pembrolizumab arm (2.0%), and 14 in the chemotherapy arm (2.3%).