Adjuvant pembrolizumab versus placebo in resected stage III melanoma (EORTC 1325-MG/KEYNOTE-054): long-term, health-related quality-of-life results from a double-blind, randomised, controlled, phase 3 trial.

Background: In the European Organisation for Research and Treatment of Cancer (EORTC) 1325-MG/KEYNOTE-054 study, adjuvant pembrolizumab improved recurrence-free survival and distant-metastasis-free survival in patients with resected stage III melanoma. Earlier results showed no effect of pembrolizumab on health-related quality of life (HRQOL). Little is known about HRQOL after completion of treatment with pembrolizumab, an important research area concerning patients who are likely to become long-term survivors. This study reports long-term HRQOL results.

Methods: This double-blind, randomised, controlled, phase 3 trial compared adjuvant pembrolizumab with placebo in patients aged 18 years or older with previously untreated stage IIIA, IIIB, or IIIC resected cutaneous melanoma and an Eastern Cooperative Oncology Group performance status score of 1 or 0, recruited from 123 academic centres and community hospitals in 23 countries. Patients were randomly assigned (1:1) with a minimisation technique stratified for stage and geographical region to receive 200 mg of intravenous pembrolizumab or placebo every 3 weeks for up to 18 doses. Investigators, patients, and those collecting or analysing data were masked to group assignment. The primary endpoint of the trial was recurrence-free survival (reported elsewhere). HRQOL was a prespecified exploratory endpoint, measured with the EORTC Quality of Life Questionnaire-Core 30. All patients with a baseline HRQOL evaluation available who were alive 108 weeks from randomisation were included in this analysis of long-term HRQOL. Long-term HRQOL included assessments measured every 6 months between 108 weeks and 48 months after randomisation. The threshold of clinical relevance for all HRQOL scales used was an average change of 5 points. The trial is ongoing, recruitment is completed, and HRQOL data collection is finalised. This study is registered with ClinicalTrials.gov, NCT02362594, and EudraCT, 2014-004944-37.

Findings: Between Aug 26, 2015, and Nov 14, 2016, 1019 patients were randomly assigned to pembrolizumab (n=514) or placebo (n=505). Completion of the HRQOL evaluation at baseline exceeded 90% (481 [94%] patients in the pembrolizumab group and 467 [92%] in the placebo group), and ranged between 60% and 90% for post-baseline timepoints. Among patients with a baseline HRQOL evaluation, 365 (39%) were female and 583 (61%) were male. The mean change from baseline to long-term HRQOL was -0·56 (95% CI -2·33 to 1·22) in the pembrolizumab group and 1·63 (-0·12 to 3·38) in the placebo group. The difference between the two groups was -2·19 (-4·65 to 0·27, p=0·081). Differences for all other scales were smaller than 5 and not statistically significant.

Interpretation: Adjuvant pembrolizumab did not have a significant impact on long-term HRQOL compared with placebo in patients with resected stage III melanoma. These findings, together with earlier results on efficacy and HRQOL, support the use of pembrolizumab in this setting.

Funding: Merck Sharp & Dohme.