On February 15, 2019, the FDA approved pembrolizumab (Keytruda; Merck) for the adjuvant treatment of patients with melanoma and involvement of lymph node(s) after a complete resection. This is the second melanoma-related indication for pembrolizumab, which was previously approved by the FDA for the treatment of patients with unresectable or metastatic melanoma.
This latest approval was based on a phase 3, randomized, double-blind, placebo-controlled clinical trial of 1019 patients with resected stage IIIA, IIIB, or IIIC melanoma. Patients had to have complete resection of the melanoma with negative margins, lymph node dissection, and, if indicated, completion of radiotherapy within 13 weeks before the start of treatment. Patients were randomized to pembrolizumab 200 mg every 3 weeks or to placebo for up to 1 year until disease recurrence or unacceptable toxicity. The primary end point was recurrencefree survival.
The results showed that patients in the pembrolizumab arm achieved significantly longer recurrence-free survival (hazard ratio, 0.57; 95% confidence interval, 0.46-0.70; P <.001). The median recurrence-free survival was not reached in the pembrolizumab arm and was 20.4 months in the placebo arm. Pembrolizumab showed a recurrence-free survival benefit versus placebo, regardless of PD-L1 expression on the tumor.
The most common (≥10%) adverse events with pembrolizumab were diarrhea, pruritus, nausea, arthralgia, hypothyroidism, cough, rash, asthenia, influenzalike illness, weight loss, and hyperthyroidism.
