Safety and efficacy of sirolimus in recurrent intravenous leiomyomatosis, pulmonary benign metastatic leiomyomatosis, and leiomyomatosis peritonealis disseminata: a pilot study

Background: Intravenous leiomyomatosis (IVL), pulmonary benign metastatic leiomyomatosis (PBML), and leiomyomatosis peritonealis disseminata (LPD) are leiomyomas with special growth patterns and high postoperative recurrence rates. We report the safety and efficacy of a pilot study of sirolimus in the treatment of recurrent IVL, PBML, and recurrent LPD.

Methods: This was a pilot study to evaluate the safety and efficacy of sirolimus in the treatment of leiomyomatosis (ClinicalTrials.gov identifier NCT03500367) conducted in China. Patients received oral sirolimus 2 mg once a day for a maximum of 60 months or until disease progression, intolerable toxicity, withdrawal of consent, or investigator decision to stop. The primary end point of this study was the objective response rate. Secondary end points included safety and tolerability, disease control rate, and progression-free survival.

Results: A total of 15 patients with leiomyomatosis were included in the study, including five with recurrent IVL, eight with PBML and two with recurrent LPD. The median follow-up time was 15 months (range 6-54 months), nine patients (60%) had treatment-related adverse events (including all levels), and two patients had treatment-related grade 3 or 4 adverse events. The objective response rate was 20.0% (95% CI, 7.1-45.2%), and the disease control rate was 86.7% (95% CI, 62.1-96.3%). Partial response was achieved in three patients. The median response time in the three partial response patients was 33 months (range 29-36 months), and the sustained remission time of these three patients reached 0, 18, and 25 months, respectively.

Conclusions: Sirolimus was safe and effective in the treatment of recurrent IVL, PBML, and recurrent LPD.

Trial registration: ClinicalTrials.gov identifier NCT03500367. Registered on 18 April 2018.