Purpose: Nivolumab (NIVO) + ipilimumab (IPI) combination and NIVO monotherapy have demonstrated durable clinical benefit in patients with unresectable/metastatic melanoma. This analysis describes long-term overall survival (OS) with the combination or monotherapy pooled across all major company-sponsored trials, as well as clinical factors associated with survival, in patients with immune checkpoint inhibitor (ICI) treatment-naïve unresectable/metastatic melanoma.
Methods: Data were pooled from six CheckMate studies in ICI treatment-naïve patients receiving NIVO + IPI (NIVO 1 mg/kg + IPI 3 mg/kg or NIVO 3 mg/kg + IPI 1 mg/kg) or NIVO monotherapy (3 mg/kg). OS was assessed for each treatment, as well as in select subgroups. Cox proportional multivariate analysis (MVA) and classification and regression tree (CART) analyses were performed within treatment arms.
Results: Median follow-up for OS was 45.0 months for patients treated with NIVO + IPI (n = 839) and 35.8 months for patients treated with NIVO (n = 536). OS was longer with NIVO + IPI versus NIVO monotherapy (hazard ratio, 0.78 [95% CI, 0.67 to 0.91]), with 6-year OS rates of 52% versus 41%, respectively. Consistent benefit was observed in BRAF-mutant and BRAF-wild-type patients and those with normal and elevated lactate dehydrogenase (LDH). Numerical difference in OS was also observed across PD-L1 expression levels, although more pronounced with no/low PD-L1 expression. Clinical factors associated with decreased survival in both the MVA and CART analyses were LDH > upper limit of normal with either treatment, age ≥65 years with NIVO + IPI, and the presence of liver metastases with NIVO monotherapy.
Conclusion: In this large, pooled nonrandomized retrospective analysis, we observed that NIVO + IPI provides longer OS than NIVO in patients with ICI treatment-naïve advanced melanoma and identifies clinical factors that appear to be associated with survival for each treatment, which may assist with treatment decision making.