506 Response to treatment of cutaneous immune-related adverse events following immune checkpoint inhibitor therapy

Cutaneous immune-related adverse events (cirAEs) are among the most prevalent adverse events in response to immune checkpoint inhibitors (ICIs). CirAE treatment is typically directed towards symptomatic management and influenced by cirAE phenotype, though treatment optimization remains challenging. This single-institution retrospective cohort study was performed to characterize the response of ICI-induced cirAEs to the maximum potency treatment utilized in their care. Clinical data was collected for patients who received ICI therapy between 1/1/16 – 6/29/21 including demographics, medical history, cirAE features, physical exam, treatments, and clinical course. CirAE severity was determined using the Common Terminology Criteria for Adverse Events 5.0, with “0” indicating cirAE resolution. Most potent cirAE-directed treatments were categorized into non-medicated emollients, non-steroid topicals, topical steroids, oral anti-itch medications, and systemic immunomodulatory agents. A total of 628 patients were included. Mean severity in response to the most potent cirAE-directed treatment ranged between 0.449 to 0.963 across treatment categories. A subgroup of patients (n=79, 12.8%) experienced complete cirAE resolution with non-medicated emollients as their maximum potency treatment (supportive care). The nonspecific rash morphology was found to be significantly overrepresented in this subgroup (p<0.001). Eczematous and mucositis morphologies were less likely to resolve with supportive care only (p=0.014, p=0.052, respectively). CirAE-directed treatment can contribute to symptomatic improvement, but complete resolution is difficult to achieve. A subgroup of patients is identified who achieved resolution of cirAEs with non-medicated emollients only, a phenomenon associated with nonspecific rashes not categorized into more specific morphologies by diagnosing providers.