Among patients with advanced melanoma, the human programmed death receptor-1 (PD-1)-blocking antibody pembrolizumab was associated with an overall objective response rate of 33%, 12-month progression-free survival rate of 35%, and median overall survival of 23 months, according to pooled data from phase 1b clinical trials.1
Pembrolizumab was initially approved under accelerated approval based on tumor response rate and duration of response by the U.S. Food and Drug Administration (FDA). It is indicated for the treatment of patients with unresectable or metastatic melanoma who experienced disease progression following ipilimumab and, if BRAF V600 mutation-positive, a BRAF inhibitor.
In this study, researchers analyzed data from 655 patients with advanced or metastatic melanoma enrolled in open-label, multicohort, phase 1b clinical trials between December 2011 and September 2013. Median duration of follow-up was 21 months.
The results, which were published in JAMA, showed that the objective response rate was 33% (95% CI, 30-37) among 581 evaluable patients and 45% (95% CI, 36-54) among treatment-naïve patients. Overall, 74% of responses were ongoing at the time of data cutoff, with 90 patients achieving a response duration for at least 1 year.
Researchers found that 12-month progression-free survival rates were 35% (95% CI, 31-39) overall and 52% (95% CI, 43-60) among treatment-naïve patients. Median overall survival was 23 months (95% CI, 20-29) and 31 months (95% CI, 24-not reached) in the total population and among treatment-naïve patients, respectively.
In terms of safety, 14% of patients experienced at least 1 treatment-related grade 3 or 4 adverse event. Four percent of patients discontinued pembrolizumab therapy due to treatment-related toxicity and 9% of patients had treatment-related serious adverse events.
1. Ribas A, Hamid O, Daud A, et al. Association of pembrolizumab with tumor response and survival among patients with advanced melanoma. JAMA. 2016;315(15):1600-1609.