Phase 2 study of the safety and efficacy of QTORIN rapamycin in the treatment of microcystic lymphatic malformations

Objectives: The objective of this Phase 2 study was to determine the safety and efficacy of QTORIN rapamycin 3.9% anhydrous gel for the treatment of cutaneous microcystic lymphatic malformations (LM). Design: The study was a multicenter, baseline-controlled Phase 2 clinical trial. Setting: The study was performed at 5 clinical sites in the United States. Participants: Participants were ≥6 years old with a clinical diagnosis of cutaneous microcystic LM. Intervention: Participants self-administered topical QTORIN rapamycin once daily for 12 weeks. Main Outcome Measurements: Outcomes were measured via standardized clinician- and patient-reported outcomes, including clinician global impression of change, clinician global impression of severity (CGI-S), patient global impression of severity, patient global impression of change (PGI-C), as well as lesion leaking or bleeding, thickness/height/size of lesion, LM symptom severity scale, dermatology life quality index, and overall patient satisfaction. Results: Safety, clinical examinations, laboratory evaluations, and quantification of sirolimus blood levels, suggested that QTORIN rapamycin was generally safe and well-tolerated. Efficacy indicated statistically significant improvements in endpoints with treatment. Clinician and patient reports were supported by visual photographs showing significant improvement in lesions over the course of treatment. Conclusions: This Phase 2 study provides compelling evidence of the safety and efficacy of QTORIN rapamycin, a novel 3.9% topical sirolimus formulation, for the treatment of microcystic LM and supports further development including a larger trial in this patient population.