Long-term toxicities with immune checkpoint inhibitor (ICI) in melanoma patients.

Abstract

e21549 Background: The incorporation of ICI into the treatment of melanoma has greatly improved patient outcomes, but this benefit has come at the cost of exposing patients to immune-related adverse events (irAEs). A wide spectrum of irAE types has been described, and severity is known to vary from minor to life-threatening; however, the literature to date on the chronicity of irAEs is limited. Objectives: To characterize the long-term and permanent irAEs associated with ICI treatment in patients with melanoma, the treatment of irAEs and the association with survival outcomes. Methods: We performed a retrospective chart review of 161 adult patients with melanoma treated with at least one cycle of ICI regimen in the adjuvant or metastatic setting: 129 patients received PD-1 inhibitor monotherapy and 32 received dual immunotherapy. Patients were grouped by duration of irAE: permanent (no complete resolution), long-term (resolution over a period ≥6 months), transient (resolution over a period < 6 months), or no irAEs. Overall survival was evaluated for those patients that were treated in the metastatic setting with PD1 inhibitor monotherapy. Results: Thirty-eight patients were treated in the adjuvant setting and 123 patients were treated in the metastatic setting. A total of 279 irAEs were reported in the whole patient population. Sixty-six (41.0%) patients developed permanent irAEs, 15 (9.3%) experienced long-term irAEs as their longest-lasting toxicity, 34 (21.1%) developed transient irAEs only, and 46 (28.6%) experienced no irAEs. Permanent irAEs occurred in 21 (65.6%) patients treated with dual immunotherapy and in 45 (34.9%) patients treated with monotherapy. The majority of permanent irAEs were endocrine-related (35.5%) or skin-related (32.7%). Grade ≥3 permanent irAEs occurred in 20 (12.4%) patients and included toxicities such as adrenal insufficiency, myocarditis, and myelitis. Fifty-three (32.9%) patients were still on treatment for long-term or permanent irAEs 6 months or more following completion of ICI therapy, including 23 patients on thyroid replacement and 22 on oral steroids. ICI treatment was temporarily interrupted for 63 (22.6%) irAEs and permanently discontinued due to irAE in 38 (13.6%) patients. Subgroup analysis of patients who received single-agent ICI in the first-line palliative setting reveals that those with longer-duration irAEs had a significantly longer median overall survival. Conclusions: Despite the significant benefits, treatment with ICIs in melanoma is associated with a wide range of toxicities that can be permanent and may have long-lasting impacts on patients. The risk of long-term toxicity should therefore be discussed when obtaining consent for treatment. As these treatments are being used more commonly in the adjuvant setting, the impact of survivorship and the long-term management of these toxicities is increasingly important.