Importance: Since 2011, many patients with metastatic melanoma have been treated with ipilimumab therapy and have developed severe immune-related adverse events (AEs). Because several immune therapies are now available to treat metastatic melanoma, a better knowledge of mechanisms and recurrence risks of immune-related AEs is needed before reintroduction of immunotherapies.
Objectives: To evaluate the risk of a recurrence of immune toxic effects associated with anti-programmed cell death 1 antibody (anti-PD-1) therapy after discontinuation of ipilimumab monotherapy because of severe AEs.
Design, settings, and participants: This cohort study conducted at 19 French melanoma referral centers included patients with metastatic melanoma who experienced severe immune-related AEs after ipilimumab therapy and then were treated with anti-PD-1 therapy between February 1, 2013, and December 31, 2016. The study cutoff was June 1, 2017. Statistical analysis was performed from June 1, 2016, to August 31, 2017.
Exposures: Monotherapy with at least 1 cycle of ipilimumab that was associated with a grade 3 or 4 immune-related AE and subsequent treatment with at least 1 cycle of an anti-PD-1 (nivolumab or pembrolizumab) therapy.
Main outcomes and measures: The primary outcome was the rate of immune-related AEs associated with anti-PD-1 therapy. Secondary outcomes were characteristics of ipilimumab-related and anti-PD-1 immune-related AEs and overall response rate and overall survival associated with anti-PD-1 therapy.
Results: Of 56 patients with metastatic melanoma included in the study, all of whom experienced severe immune-related AEs after ipilimumab therapy (31 [55%] male; mean [SD] age, 64 [14.9] years), 20 (36%) experienced at least 1 immune-related AE associated with pembrolizumab (6 of 20 [30%]) or nivolumab (14 of 20 [70%]) therapy. A total of 12 patients (21%) experienced grade 3 or 4 immune-related AEs, and among these patients, 4 (33%) presented with the same immune-related AE as with ipilimumab therapy. Severe immune-related AEs were resolved with use of systemic corticosteroids (7 [58%]) and/or anti-tumor necrosis factor (1 [8%]), and no grade 5 toxic effects were reported. Five patients discontinued anti-PD-1 therapy because of immune-related AEs. The overall response rate was 43%, with a median overall survival of 21 months (interquartile range, 18 to ongoing).
Conclusions and relevance: The findings suggest that anti-PD-1 therapy may be associated with reduced risk of toxic effects and improved survival among patients who have experienced severe toxic effects after ipilimumab therapy.