Tazarotene: Randomized Double-Blind Vehicle-Controlled and Open-Label Concurrent Trials for Basal Cell Carcinoma Prevention and Therapy in Patients with Basal Cell Nevus Syndrome

摘要

Sporadic human basal cell carcinomas (BCCs) are generally well managed with current surgical modalities. However in the subset of high-risk patients predisposed to developing large numbers of BCCs, there is an unmet need for effective, low morbidity chemoprevention. This population includes fair-skinned patients with extensive sun exposure and those with genodermatoses such as the basal cell nevus (Gorlin) syndrome (BCNS). Tazarotene (Tazorac, Allergan) is a topical retinoid with relative specificity for RAR-β and RAR-γ receptors. We previously demonstrated tazarotene’s robust anti-BCC efficacy in Ptch1+/- mice, a murine equivalent of BCNS, and others have found it to have some efficacy against sporadic human BCCs. We report here results of a randomized, double-blind, vehicle-controlled study in BCNS patients evaluating the efficacy of topically applied tazarotene for BCC chemoprevention (N=34 subjects), along with an open-label trial evaluating tazarotene’s efficacy for chemotherapy of BCC lesions (N=36 subjects) for a maximum follow-up period of 3 years. We found that only 6% of patients had a chemopreventive response and that only 6% of treated BCC target lesions were clinically cured. Our studies provide no evidence for either chemopreventive or chemotherapeutic effect of tazarotene against BCCs in patients with BCNS. We hypothesize that the discrepancy between the efficacy seen in Ptch1+/- mice as compared to that seen in PTCH1^+/-, BCNS patients, may relate to the superior barrier function of human skin and the greater depth of human BCCs.