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NCT Number: NCT06722586

Sirolimus Monotherapy in the Treatment of Antiphospholipid Antibody Related Thrombocytopenia

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

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Key information

Conditions

Antiphospholipid (aPL)-Positive Blood Platelet Disorders Cytopenia Hematologic Diseases Hemic and Lymphatic Diseases Thrombocytopaenia Thrombocytopenia

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Xiangya Hospital of Central South University, Changsha, Hunan, China

Loading trial locations.

About this study

Complete response: the platelet count is more than or equal to 100×10^9/L Partial response: If the platelet count is less than 100×10^9/L, it should be more than 2 times of the baseline count Overall response: both complete and partial response

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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).

Exclusion criteria

  • fulling the criteria of other connective tissue disease other than antiphospholipid syndrome
  • received oral/intravenous antibiotics within 2 weeks before the enrollment.
  • new onset of thrombosis within 4 weeks before the enrollment.
  • apparent bleeding tendency.
  • life or organ threatening manifestations, includes but not limit to catastrophic antiphospholipid syndrome and thrombotic microangiopathy.
  • liver and renal dysfunction: ALT or AST more than three times of upper limit of normal range; eGFR<40mL/min/1.73m^2
  • hematocytopenia: WBC<3.0×10^9/L, Hb<100g/L.
  • uncontrollable hyperlipidemia: low density lipoprotein cholesterol>3.1 mmol/L, triglycerides>2.3 mmol/L after lipid lowering therapy.
  • current active infection
  • women in pregnancy and postpartum period

Treatment and study plan

sirolimus

Drug

Sirolimus 1 mg (two pills) once daily during the 6-month double-blind phase; sirolimus 1.5 mg once daily during the optional 3-month open-label extension for eligible participants.

Other names: Rapamycin, mTOR inhibitor

Placebo

Drug

Matching placebo two pills once daily during the 6-month double-blind phase; sirolimus 1.5 mg once daily during the optional 3-month open-label extension for eligible participants.

Primary outcomes

  1. Percentage of participants with overall response at Month 6

    Time frame: Month 6

    Overall response is defined as achieving either complete response or partial response. Complete response is defined as platelet count >=100 x 10^9/L. Partial response is defined as platelet count <100 x 10^9/L with at least a 2-fold increase from baseline. Participants with missing Month 6 assessment or meeting prespecified treatment failure criteria will be counted as non-responders.

Secondary outcomes

  1. Percentage of participants with overall response at Month 1

    Time frame: Month 1

    Overall response is defined as achieving either complete response or partial response. Complete response is defined as platelet count >=100 x 10^9/L. Partial response is defined as platelet count <100 x 10^9/L with at least a 2-fold increase from baseline. Participants with missing Month 1 assessment or meeting prespecified treatment failure criteria will be counted as non-responders.

  2. Percentage of participants with overall response at Month 3

    Time frame: Month 3

    Overall response is defined as achieving either complete response or partial response. Complete response is defined as platelet count >=100 x 10^9/L. Partial response is defined as platelet count <100 x 10^9/L with at least a 2-fold increase from baseline. Participants with missing Month 3 assessment or meeting prespecified treatment failure criteria will be counted as non-responders.

  3. Percentage of participants with complete response at Month 6

    Time frame: Month 6

    Complete response is defined as platelet count >=100 x 10^9/L.

  4. Percentage of participants with partial response at Month 6

    Time frame: Month 6

    Partial response is defined as platelet count <100 x 10^9/L with at least a 2-fold increase from baseline.

  5. Change from baseline in Global Antiphospholipid Syndrome Score (GAPSS) at Month 6

    Time frame: Baseline and Month 6

    GAPSS will be calculated at baseline and Month 6 according to the prespecified scoring algorithm based on antiphospholipid antibody profile and cardiovascular risk factors. The outcome will be reported as the change in GAPSS from baseline to Month 6, calculated as Month 6 GAPSS minus baseline GAPSS. A negative value indicates a decrease in GAPSS.

  6. Change from baseline in oral glucocorticoid dose at Month 6

    Time frame: Baseline and Month 6

    Oral glucocorticoid dose will be converted to prednisone-equivalent dose and summarized as the change from baseline to Month 6.

Other outcomes

  1. Percentage of open-label extension participants with overall response at Month 9

    Time frame: Month 9

    Overall response is defined as achieving either complete response or partial response. Complete response is defined as platelet count >=100 x 10^9/L. Partial response is defined as platelet count <100 x 10^9/L with at least a 2-fold increase from baseline.

  2. Number of participants with serious adverse events during the double-blind treatment phase

    Time frame: From first dose through Month 6

    Serious adverse events occurring after initiation of study treatment through the end of the 6-month double-blind treatment phase.

Study contacts

Contact information is provided by the study sponsor or research team.

Lanlan Ji

CONTACT

[email protected]

+86-010-83575130

Sponsors and collaborators

Lead sponsor

Peking University First Hospital

Other

Collaborators

  • North China Pharmaceutical Co.,Ltd

Registry information

Official study title

Sirolimus Monotherapy in the Treatment of Antiphospholipid Antibody Related Thrombocytopenia: a Multicenter Randomized, Double Blind, Placebo Controlled, Clinical Trial

Acronym: SMART

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Dec 9, 2024
Registry last updated
Jun 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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