Adjuvant pembrolizumab significantly improved distant metastasis-free survival (DMFS), with continued reduction in the risk of recurrence, compared with placebo in patients with resected stage IIB and IIC melanoma, according to research presented at the 2022 ASCO Annual Meeting.

These results come from the KEYNOTE-716 trial ( Identifier: NCT03553836), which enrolled patients (aged 12 years and older) with complete resection of cutaneous stage IIB or IIC melanoma and negative sentinel lymph node biopsy.

The patients were randomly assigned to receive pembrolizumab (2 mg/kg for pediatric patients and 200 mg IV for adult patients) or placebo every 3 weeks for 17 cycles (approximately 1 year). The data cutoff for the interim analysis was January 4, 2022.

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A total of 976 patients were included in the study, with 487 in the pembrolizumab arm and 489 in the placebo arm. Baseline characteristics were well balanced between the arms. The median age was 60 years (range, 16 to 84) in the pembrolizumab arm and 61 years (range, 17 to 87) in the placebo arm.

At median follow-up of 27.4 months, adjuvant pembrolizumab significantly improved DMFS compared with placebo (hazard ratio [HR], 0.64; 95% CI, 0.47-0.88; P =.0029; median not reached [NR] for both). The 24-month DMFS rate was 88.1% with pembrolizumab and 82.2% with placebo.

At a median follow-up of 37.2 months, the risk of recurrence was consistently reduced with pembrolizumab relative to placebo (HR, 0.64; 95% CI, 0.50-0.84). The 24-month recurrence-free survival rate was 81.2% with pembrolizumab and 72.8% with placebo.

Grade 3 or higher any-cause adverse events (AEs) occurred in 28% of patients in the pembrolizumab arm and 20% of those in the placebo arm. Grade 3 or higher drug-related AEs occurred in 17% and 5%, respectively.

No drug-related deaths occurred. Immune-mediated AEs occurred in 38% of the pembrolizumab arm and 9% of the placebo arm. The most common was hypothyroidism (16% vs 3%).

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  


Long GV, Luke JJ, Khattak M, et al. Distant metastasis-free survival with pembrolizumab versus placebo as adjuvant therapy in stage IIB or IIC melanoma: the phase 3 KEYNOTE-716 study. Presented at ASCO 2022; June 3-7, 2022. Abstract LBA9500.