Ipilimumab after progression on anti-PD-1 treatment in advanced melanoma

While both efficacy and safety of anti-PD-1 agents seem to be independent of previous treatment with anti-CTLA-4, limited data exist of efficacy and toxicity of ipilimumab after progression on anti-PD-1 therapy. This retrospective analysis describes the efficacy and safety of sequential therapy with ipilimumab in patients with metastatic melanoma who progressed on anti-PD-1 antibody.

Nine patients who progressed on anti-PD-1 therapy received four cycles of ipilimumab 3 mg/kg every 3 weeks.

Two out of nine patients (2/9; 22.2%) showed a partial response, and seven patients (7/9; 77.8%) experienced disease progression. Median progression-free survival was 3.14 months (95% CI: 2.56-3.71), and the median overall survival since the start of anti-PD-1 therapy was 16.8 months (95% CI: 8.1-25.4). Five (5/9; 55.6%) patients experienced grade 3 immune-related adverse events. No grade 4 or 5 adverse events were reported.

In this small retrospective series of cases, the efficacy of ipilimumab post-anti-PD-1 was similar to that described in the previous reports on ipilimumab.