In a multicohort, open label landmark phase 1 study the anti-programmed death 1 monoclonal antibody pembrolizumab was assessed for advanced or metastatic NSCLC. The authors now report the 3-year efficacy and safety outcomes. In this study 550 patients (449 previously treated patients and 101 treatment naïve patients) were enrolled. Patients were assigned to treatment in 3 different doses (2mg/kg per 3 weeks, 10mg/kg per 2 weeks, 10mg/kg per 3 weeks).
The primary analysis was the proportion of patients with an objective response. 41% (95% CI : 30.9-50.8) of the treatment naïve patients, and 23% (95% CI : 18.9-26.9 ) of the previously treated patients reached this end point. The median overall survival for treatment naïve patients as 22.3 month (95% CI : 17.1-31.5) and 10.5 month (95% CI: 8.6-13.2) for the previously treated patients. The PD-L1 subgroup with a PD-L1 of 50% or higher had a longer median overall survival for both the treatment naïve as the previously treated patients. Severe toxicity occurred in 66 out of the 550 patients, of whom 30 discontinued treatment.
Comment
This phase one study provides evidence that pembrolizumab monotherapy provides a sustainable effect on overall survival and acceptable safety for patients with advanced or metastasized non-small-cell lung cancer. Long term data of randomized trials with pembrolizumab compared with standard treatment regimens are needed to confirm these results.