Sirolimus Monotherapy in the Treatment of Antiphospholipid Antibody Related Thrombocytopenia: a Multicenter Randomized, Double Blind, Placebo Controlled, Clinical Trial
The goal of this clinical trial is to evaluate the efficacy and safety of sirolimus in patients with anti-phospholipid antibody-associated thrombocytopenia. In the 6-month randomized, double-blind, placebo-controlled phase, participants will receive either sirolimus 1 mg once daily or matching placebo. Participants will be followed at 2 weeks, 1 month, 3 months, and 6 months after enrollment. Participants who do not achieve the primary endpoint at 6 months may enter a 3-month open-label extension and receive sirolimus 1.5 mg once daily, with follow-up through month 9. The main question is whether sirolimus improves the overall response rate at 6 months compared with placebo. Primary outcome: \- Overall response rate at 6 months Secondary outcomes: * Overall response rate at 1 month and 3 months * Complete response rate at 6 months * Partial response rate at 6 months * Change in anti-phospholipid antibody titers at 6 months * Change in oral glucocorticoid dosage at 6 months Exploratory outcomes: * Proportion and reasons for early discontinuation during the double-blind phase * Among participants who do not achieve the primary endpoint at 6 months and enter the open-label extension, overall response rate, complete response rate, partial response rate, and safety outcomes after 3 months of open-label treatment
• persistent positive of antiphospholipid antibody (either lupus anticoagulant, anti-cardiolipin antibody, or anti-b2GP1 antibody, at least two times with 12 weeks apart)
• persistent thrombocytopenia (30-100×10\^9/L, at least for 2 weeks)
⁃ Eligible concomitant treatment:
• prednisone or equivalent dose less than 10mg per day is allowed, and dose should be stable for more than 2 weeks
• hydroxychloroquine less than 400mg per day is allowed, and dose should be stable for more than 1 month
• anti-platelet and/or anti-coagulant therapy is allowed, and strength should be the stable for 1 week
• these following therapies should be discontinued for more than 5 half-lives before the enrollment, including thrombopoietin or thrombopoietin receptor antagonist, intravenous immunoglobulin, immunosuppressants, B cell inhibitors (Belimumab or Talitacicept) and B cell depletion therapy (Rituximab or Obinutuzumab).