Indirect Treatment Comparison of Nivolumab Versus Observation or Ipilimumab as Adjuvant Therapy in Resected Melanoma Using Pooled Clinical Trial Data.

INTRODUCTION: Nivolumab has been approved in patients with melanoma with lymph node involvement or metastatic disease who have undergone complete resection, in the adjuvant setting. A pivotal trial compared nivolumab with ipilimumab; however, no head-to-head trial exists comparing nivolumab to observation, a common comparator in the adjuvant setting. Here, we compared the efficacy and cost-effectiveness of nivolumab with observation or ipilimumab as adjuvant therapies in resected stage IIIB/C melanoma. METHODS: Patient data were pooled from the EORTC 18071 and CheckMate 238 trials using propensity score weighting and adjusting for cross-trial differences. Number needed to treat (NNT) and costs per recurrence-free life-month (RFLM) at 12, 16, 18, and 24 months (as data allowed) were estimated. Costs included drug acquisition, administration costs, and direct medical costs. Sensitivity analyses including patients with stage IIIB/C and resected stage IV melanoma were conducted. RESULTS: A total of 1287 patients (278 nivolumab, 365 observation, and 644 ipilimumab) with resected stage IIIB/C melanoma were pooled. NNTs to achieve one additional recurrence-free survivor with nivolumab versus observation were 3.93 at 12 months and 3.42 at 24 months; NNTs for nivolumab versus ipilimumab were 7.97 at 12 months and 6.43 at 24 months. Mean drug costs per RFLM were lower for nivolumab at 12, 18, and 24 months, respectively (nivolumab: $13,447, $9462, and $7370; ipilimumab: $52,734, $40,484, and $33,875). Mean medical costs per RFLM were the lowest for nivolumab versus observation or ipilimumab at 12 months ($449 versus $674 or $1531) and 16 months ($383 versus $808 or $1316). The sensitivity analysis results were consistent with the base case. CONCLUSION: For resected melanoma, adjuvant nivolumab is both clinically effective and cost-effective compared with observation or ipilimumab. Adjuvant nivolumab was associated with a lower drug cost per RFLM compared with ipilimumab, and a lower medical cost compared with observation. Future analyses incorporating long-term follow-up data may help increase understanding of the economic impact of nivolumab in the adjuvant setting. FUNDING: Bristol-Myers Squibb Company.