Dermatological adverse events under programmed cell death-1 inhibitors as a prognostic marker in metastatic melanoma

Melanoma is widely treated with programmed cell death-1 (PD-1) inhibitors. As part of their anti-tumor immunity effect, they increase the susceptibility to cutaneous immune-related adverse events (cIRAE) among other autoimmune effects. To characterize the manifestations of cIRAE in melanoma patients treated with PD-1 inhibitors, and evaluate the correlation with tumor response. A retrospective study of 95 metastatic malignant melanoma patients treated with PD-1 inhibitors at the Hadassah Medical Center during 2013-2016. The most common cIRAE was pruritus reported by 39 (41%) patients. All other cIRAE were noted in 34 patients (35.8%), of which the most common cutaneous manifestation was vitiligo, demonstrated in 17 patients (17.9%) followed by various rashes (7.4%, including erythema multiforme, oral lichen planus, photosensitive rash, insect bite-like reaction, and urticaria), psoriasiform rash (3.2%), bullous pemphigoid (3.2%), and eczema (1%). Interestingly, higher response rates to immunotherapy were demonstrated in patients who developed pruritus (85%) and cIRAE (88%), with lower mortality rates in the cIRAE group (38.2%) versus the non-cIRAE group (70.5%, p = 0.002). cIRAE are common among malignant melanoma patients treated with PD-1 inhibitors and may be a marker for favorable prognosis.