Indirect treatment comparison of nivolumab versus placebo as adjuvant treatment for resected melanoma

Background: Nivolumab (an anti–programmed death-1 antibody) is an adjuvant standard of care for patients with high-risk resected melanoma, although a watch-and-wait strategy remains an option. In the absence of head-to-head evidence, an indirect treatment comparison (ITC) of adjuvant nivolumab versus placebo, the proxy for a watch-and-wait strategy, was conducted in patients with high-risk resected melanoma. Methods: An ITC using the Bucher method compared nivolumab with placebo using intention-to-treat population data from the phase III CheckMate 238 (nivolumab vs ipilimumab; minimum follow-up, 4 years; NCT02388906) and European Organisation for Research and Treatment of Cancer (EORTC) 18071 (ipilimumab vs placebo; minimum follow-up, ≈4.5 years; NCT00636168) trials. The end-points were recurrence-free survival (RFS), distant metastasis-free survival (DMFS) and overall survival (OS). To account for cross-trial differences in staging and subsequent therapy, additional analyses examined patients with stage IIIB/IIIC disease and adjusted post-recurrence survival in EORTC 18071, respectively. Results: Nivolumab versus placebo was associated with clinically meaningful improvements in RFS (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.42–0.68) and OS (HR, 0.63; 95% CI, 0.45–0.89). Nivolumab versus placebo was also associated with clinically meaningful improvements in RFS (HR, 0.53; 95% CI, 0.40–0.69), DMFS (HR, 0.62; 95% CI, 0.46–0.83) and OS (HR, 0.67; 95% CI, 0.47–0.97) in patients with stage IIIB/IIIC disease and in OS (HR, 0.65; 95% CI, 0.46–0.92) in the overall population after adjusting post-recurrence survival in EORTC 18071. Conclusion: This ITC shows that adjuvant nivolumab provides clinically meaningful improvements in RFS, DMFS and OS versus a watch-and-wait strategy in high-risk resected melanoma.