Efficacy and Safety of Topical Sirolimus Therapy for Facial Angiofibromas in the Tuberous Sclerosis Complex

Abstract

Inhibitors of mammalian target of rapamycin complex 1, such as sirolimus, effectively target skin lesions in tuberous sclerosis complex (TSC). However, systemic treatment causes adverse effects, and topical sirolimus has shown promise in the treatment of facial angiofibromas. To evaluate the efficacy, safety, and optimal concentration of a topical sirolimus gel vs placebo for treatment of facial angiofibromas in TSC. A double-blind, placebo-controlled, parallel-group, dose-escalation, phase 2 randomized clinical trial using 3 sirolimus gel concentrations was performed at Osaka University Hospital, Osaka, Japan. Thirty-six patients with TSC and facial angiofibromas, including 18 aged 3 to 18 years (children) and 18 aged 19 to 65 years (adults), were enrolled from December 10, 2013, to July 17, 2014. Analysis was by intention to treat. The adult and child groups were each subdivided into 3 groups (n = 12 each) and randomized to receive sirolimus gel concentrations of 0.05%, 0.1%, or 0.2% or placebo using a web-response system in a 2:1 fashion. The medication was applied to the patient's lesions twice per day for 12 weeks. Each patient underwent assessment at 2, 4, 8, and 12 weeks during treatment and at 4 weeks after discontinuation of the treatment (16 weeks). The primary end point, planned before starting data collection, was an improvement factor, represented as a variable composed of tumor size reduction and a lessening of the redness of the 3 target tumors at 12 weeks relative to baseline. All 36 patients (13 male and 23 female; median age, 40 years; range, 6-47 years) completed the study analyses. The improvement factor was statistically significant in all active treatment groups receiving 0.2% sirolimus (mean [SD], 1.94 [0.68]; P < .001) and not in the adult subgroups receiving 0.1% (mean [SD], 0.88 [0.85]; P = .31) and 0.05% (mean [SD], 1.63 [1.11]; P = .09) concentrations of sirolimus. No significant adverse effects were observed. Mild skin dryness (13 patients [36%]) and irritation (11 patients [31%]) were observed. Low blood levels of sirolimus (<0.25 ng/mL) were detected in adults (1 patient [25%] in the 0.1% adult subgroup and 2 patients [50%] in the 0.2% adult subgroup) and particularly in children (1 patient [25%] in the 0.05% child subgroup, 2 patients [50%] in the 0.1% child subgroup, and 4 patients [100%] in the 0.2% child subgroup). Topical sirolimus gel is safe and effective for facial angiofibromas in TSC. The optimal concentration of sirolimus was 0.2%. umin.ac.jp Identifier: UMIN000012420.