Purpose
Prostate cancer (PCa) patients treated with apalutamide frequently develop rash. We aim to characterize apalutamide-related dermatologic adverse events (dAE) and management.
Materials and Methods
We assessed 303 PCa patients treated with apalutamide. DAE frequency and time to onset were calculated and clinicopathologic features and management described. Associations between dAE occurrence and clinical trial participation, as well as abiraterone/prednisone exposure were detected using logistic regression models.
Results
Seventy-one (23.4%) patients had all-grade dAE occurring at a median of 77 (IQR: 30-135) days post-exposure. Twenty (6.6%) dAE-related therapy interruptions included: 8 (2.6%) with dose maintained on rechallenge, 7 (2.3%) with dose reduction, and 5 (1.7%) with discontinuation. Common dAE were maculopapular rashes (33.8%) and xerosis (32.4%). Seven (77.8%) of 9 histological analyses of skin biopsies supported a drug reaction. No significant differences in laboratory hematologic, hepatic, and renal function were detected between dAE and no dAE cohorts. Most treated grade 1/2 dAE (n=29, 40.8%) required topical steroids (n=14, 19.7%); few required oral steroids (n=3, 4.2%) ±oral antihistamines. Most grade 3 dAE (n=8, 11.3%) required oral/topical steroids (n=5, 7.0%); few required topical steroids (n=3, 4.2%) ± oral antihistamines. Clinical trial patients (n=180, 59.4%) were more likely to report dAE than those in the off-trial setting (OR=5.1 [95% CI 2.55–10.12]; p <0.001). Of clinical trial patients, concomitant abiraterone/prednisone recipients (n=109 of 180, 60.6%) were more likely to report dAE (OR=3.1 [95% CI 1.53–6.17]; p=0.002).
Conclusions
Apalutamide-related dAE are frequent and can be managed with topical ±oral steroids. With expanded approval of apalutamide, dAE identification and management are essential.