Efficacy of PD-1-based immunotherapy after radiologic progression on targeted therapy in stage IV melanoma.

Abstract

OBJECTIVES

Targeted therapy (TT) is an effective treatment for advanced BRAFV600-mutated melanoma, but most patients eventually acquire resistance and progress. Here, we evaluated the outcome of second-line immune checkpoint blockade (ICB) after progression on dual BRAF and MEK inhibition.

CONCLUSIONS

PD-1 monotherapy and combined ipilimumab plus nivolumab show similar activity and outcome in patients with melanoma resistant to BRAF + MEK inhibition. However, combined ipilimumab plus nivolumab was associated with a higher rate of treatment-related AEs compared with monotherapy.

METHODS

Patients with metastatic melanoma progressing on combined BRAF + MEK inhibition and receiving second-line ICB between 2015 and 2019 in 9 tertiary referral centres were enrolled. Demographic and clinical data and blood counts of all patients were collected retrospectively.

RESULTS

We identified 99 patients with stage IV melanoma receiving ICB (nivolumab, pembrolizumab [n = 39] or ipilimumab plus nivolumab [n = 60]) after progression on combined TT. The median progression-free survival was similar in the PD-1 and ipilimumab plus nivolumab group (2.6 months [95% confidence interval {CI}, 2.0-3.1] vs. 2.0 [95% CI, 1.4-2.6], p = 0.15). The objective response rate was 18.0% in the PD-1 and 15.0% in the ipilimumab plus nivolumab group (p = 0.70). The disease control rate was 25.7% for monotherapy and 18.3% for combined ICB (p = 0.39). The median overall survival was 8.4 months (95% CI, 5.1-11.7) for patients receiving PD-1 monotherapy and 7.2 months (95% CI, 5.2-9.1) for patients receiving ipilimumab plus nivolumab (p = 0.86). The latter was associated with a higher rate of treatment-related adverse events (AEs). No significant association of laboratory values or clinicopathological characteristics with response to second-line ICB was observed.