Five-year results from KEYNOTE-001 shows Keytruda response in longest follow-up trial for NSCLC.

Merck Inc announced the presentation of five-year efficacy and safety data for Keytruda (pembrolizumab) as monotherapy in patients with advanced non-small cell lung cancer (NSCLC) from the first KEYNOTE trial (Phase Ib KEYNOTE-001). In this study, Keytruda demonstrated a five-year overall survival (OS) rate of 23.2% in treatment-naïve patients (n=101) and 15.5% in previously treated patients (n=449). Of note, the five-year OS rate among patients whose tumors expressed PD-L1 (tumor proportion score [TPS] ?50%) was 29.6% in treatment-naïve patients (n=27) and 25.0% in previously treated patients (n=138).

After 60.6 months (range, 51.8 to 77.9) of median follow-up, results from KEYNOTE-001 demonstrated the effect of Keytruda monotherapy across primary and secondary endpoints, including OS, objective response rate (ORR) and duration of response (DOR). The investigator-reported ORR was 41.6% (95% CI, 31.9-51.8) in treatment-naïve patients and 22.9% (95% CI, 19.1-27.1) in previously treated patients. Median DOR was 16.8 months (range, 2.1+ to 55.7+) and 38.9 months (range, 1.0+ to 71.8+), respectively. Among the 60 patients who received two or more years of treatment with Keytruda, the five-year OS rate was 78.6% in treatment-naïve patients and 75.8% in previously treated patients. The ORR in these patients was 86% and 91%, respectively. Median DOR was 52.0 months (range, 10.2 to 55.7+) in treatment-naïve patients and was not reached (range, 12.5 to 71.8+) in previously treated patients.

The safety profile of Keytruda was consistent with what has been seen in previously reported studies among patients with advanced NSCLC. Treatment-related adverse events (TRAEs) of any grade occurred in 71% (n=388) of patients receiving Keytruda; grade 3-5 TRAEs occurred in 13% (n=69) of patients. Immune-mediated adverse events were reported in 17% (n=92) of patients. Hypothyroidism was the most commonly reported immune-mediated adverse event, followed by pneumonitis, hyperthyroidism and skin toxicities. Five-year survival is a significant milestone for patients with advanced non-small cell lung cancer. These findings, which represent the longest follow-up for Keytruda in lung cancer, will be highlighted at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting.