INTRODUCTION: Selective RET inhibitors are approved for the treatment of RET-dependent cancers. A comprehensive characterization of mucocutaneous adverse events (MAEs) has not been performed
therefore, we characterized MAEs associated with the selective RET inhibitor, selpercatinib. METHODS: We assessed 133 patients with RESULTS: A total of 73 patients with mostly NSCLC (n = 46, 63%), medullary thyroid (n = 19, 26%), and papillary thyroid (n = 6, 8%) cancers had 126 predominantly grade 1/2 (n = 124, 98%) MAEs, with 48% reporting greater than one MAE. Xerostomia (n = 49, 37%), rash (n = 24, 18%), periorbital edema (n = 16, 12%), and xerosis (n = 12, 9%) were the most common MAEs. The yearly cumulative incidence of all-grade MAEs was 55%, with a median time to onset of 57 (interquartile range: 15-166) days after initiation. Those with MAEs had a significantly higher percentage of lymphocytes (mean = 21.8, SD = 11.3, CONCLUSIONS: Selective RET inhibition is associated with a unique MAE profile. Early recognition and management of MAEs may improve quality of life, minimize interruptions, and maximize therapeutic benefit.