Pembrolizumab for the adjuvant treatment of IIB or IIC melanoma.

Introduction: Up to 30% of patients with stage IIB and 50% of stage IIC melanoma experience recurrence within 5 years after radical surgery. Adjuvant treatment is expected to improve this prognosis.

Areas covered: Pembrolizumab (MK-3475) is a humanized monoclonal antibody that acts against the programmed cell death 1 (PD-1) receptor. Pembrolizumab was first approved in monotherapy for the treatment of unresectable/metastatic melanoma based on the results of the prospective KEYNOTE-001, KEYNOTE-002, and KEYNOTE-006 trials. KEYNOTE-716 is the randomized phase III trial of pembrolizumab treatment in resected stage II melanoma. Treatment with pembrolizumab is statistically significant, reducing the risk of recurrence as well as distant metastases risk after primary tumor resection. Pembrolizumab treatment has a 24-month RFS rate of 81.2% (HR 0.64 vs placebo) and a DMFS rate of 88.1%.

Expert opinion: 1-year adjuvant pembrolizumab treatment of stage IIB/C melanoma patients significantly reduces recurrence or death risk. The safety profile of adjuvant treatment is not different from previously reported and is manageable. Longer follow-up is required to fully understand the efficacy and safety of adjuvant therapy for stage II melanoma, as the number of patients needed to treat is twice as high as for stage III patients.