Key Clinical Adverse Events in Patients with Advanced Basal Cell Carcinoma Treated with Sonidegib or Vismodegib: A Post Hoc Analysis

Introduction Sonidegib is approved to treat locally advanced basal cell carcinoma (laBCC) in the USA, EU, Switzerland, and Australia and metastatic basal cell carcinoma (mBCC) in Switzerland and Australia in patients not amenable to surgery or radiotherapy. Vismodegib is approved to treat patients with mBCC, recurrent laBCC, or those not candidates for surgery or radiation. There is no head-to-head trial comparing Hedgehog inhibitors. We describe time to onset and severity of adverse events (AEs) in two studies reporting cumulative AE incidence every treatment cycle: the sonidegib phase 2 BOLT study and the expanded-access, open-label vismodegib study. Methods This analysis included patients with histologically confirmed laBCC or mBCC from BOLT who received sonidegib 200 mg once daily (QD) and patients from the vismodegib study who received vismodegib 150 mg QD. Cumulative occurrence of AEs and median time to AE onset were calculated on 30-day cycles for sonidegib and 28-day cycles for vismodegib. AEs were graded for severity using the Common Terminology Criteria for Adverse Events. Only common (at least 15% incidence) AEs were analyzed in this study. Results Over 18 treatment cycles, the most common all-grade AEs for sonidegib and vismodegib were muscle spasm (54.4% vs 70.6%; P = 0.0236), alopecia (49.4% vs 58.0%; no significant difference [NS]), and dysgeusia (43.0% vs 70.6%; P = 0.0003); incidences of diarrhea, nausea, fatigue, and weight decrease were 31.6% vs 25.2% (NS), 39.2% vs 19.3% (P = 0.0032), 32.9% vs 19.3% (P = 0.0429), and 30.4% vs 16.0% (P = 0.0217), respectively. Sonidegib-treated patients had more delayed median time to onset for all AEs than vismodegib-treated patients, except fatigue and weight decrease (NS). Most AEs reported were grade ≤ 2. Conclusion This post hoc analysis suggests lower overall incidence and slower onset of certain AEs in patients treated with sonidegib compared with vismodegib. In the absence of head-to-head comparisons, the relevance of these findings needs further studies to provide conclusive evidence.