Background: This study aims to present an interim analysis of safety data from the Spanish cohort of the NISSO post-authorization safety study on the long-term tolerability of sonidegib in patients with locally advanced basal cell carcinoma (laBCC ).

Methods: NISSO is a non-interventional, multinational, post-authorization safety study (NCT04066504). Patients with laBCC were administered sonidegib 200 mg/day and monitored for 3 years. Dose adjustments were permitted according to the Spanish prescribing information.

Results: Between January 8th, 2021, and March 7th, 2022, a total of 51 patients with laBCC were enrolled in the study in Spain (data cut June 22nd, 2023). Treatment was discontinued in 39 patients (76.5%), primarily due to treatment success (n = 11, 21.6%), patient or guardian decision (n = 8, 15.7%), and physician decision (n = 8, 15.7%). The median duration of exposure was 6.5 months (IQR, 5.69–11.91 months). A total of 45 (88.2%) patients experienced at least one treatment-emergent adverse event (TEAE). The most common TEAEs were muscle spasms (n = 23, 45.1%), alopecia (n = 23, 45.1%), and dysgeusia (n = 23, 45.1%). Cumulative rates of the above-mentioned TEAEs at 3 months were 27.5%, 11.8%, and 29.4%, respectively. Most TEAEs were grade ≤ 2. TEAEs led to treatment discontinuation in 10 patients (19.6%), while 8 (15.7%) required dose modifications due to adverse events. Serious drug-related TEAEs were reported in 2 patients (3.9%).

Conclusions: Most patients experienced grade ≤ 2 common TEAEs, such as muscle spasms, dysgeusia, and alopecia that mostly manifested 3 months into therapy. These interim results confirm the safety profile observed in the BOLT study, demonstrating that sonidegib is well-tolerated in a real-world setting in Spain.