Hydroxychloroquine for the First Thrombosis Prevention in Antiphospholipid Antibody Positive Patients
A Prospective Randomized Controlled Trial of Hydroxychloroquine in the Primary Thrombosis Prophylaxis of aPL Positive But Thrombosis-free Patients.
  • Phase

    Phase 3
  • Study Type

  • Study Participants

In this multi-center international study, our aim is to determine the effectiveness of HCQ for primary thrombosis prophylaxis in persistently aPL-positive but thrombosis-free patients without systemic autoimmune diseases.
Randomized to receive HCQ or no treatment in addition to their standard regimen. 11 study visits and 10 phone visits over 5 years.

This study was terminated at 2 years due to low recruitment rate exacerbated by manufacturing shortage and price increase of hydroxychloroquine.
Study Started
Feb 28
Primary Completion
Sep 30
Study Completion
Sep 30
Results Posted
May 04
Last Update
Sep 14

Drug Hydroxychloroquine

  • Other names: plaquenil

Standard treatment No Intervention

patients randomized to standard treatment will not receive hydroxychloroquine.

Hydroxychloroquine Experimental

Patients will be randomized to receive standard of care or standard of care + hydroxychloroquine. Dose will be weight-adjusted: 200 mg daily for patients weighing <60kg; and 400 mg daily (200 mg twice a day)for patients weighing >60kg.


Inclusion Criteria:

Persistent(at least 12 weeks apart)aPL-positivity within 12 months prior to the screening defined as:

aCL IgG/M (>40U,medium-to-high titer,and/or greater than the 99th percentile)and/or
aβ2GPI IgG/M(>40U, medium-to-high titer, and/or greater than the 99th percentile)and/or
Positive LA test based on the International Society of Thrombosis & Haematosis Recommendations

Selected Exclusion Criteria:

History of thrombosis (arterial, venous, and/or biopsy proven microthrombosis
History of Transient Ischemic Attack Confirmed by a Neurologist
SLE Diagnosis based on the ACR Classification Criteria > 4/11
Other Systemic Autoimmune Diseases diagnosed based on ACR Classification Criteria
Current Hydroxychloroquine or another antimalarial treatment (-3 months)
Current warfarin treatment (-3 months)
Current heparin therapy( -3 months)
Current pregnancy
History of Hydroxychloroquine eye toxicity
History of Hydroxychloroquine allergy
Known glucose-6-phosphate dehydrogenase deficiency


Standard Treatment


All Events

Event Type Organ System Event Term

Number of Participants With an Acute Thrombosis Event

To determine the efficacy of Hydroxychloroquine in the primary thrombosis prevention of persistently aPL-positive but thrombosis free patients with no other systemic autoimmune diseases over the five year study period.

Standard Treatment




Age, Continuous

years (Mean)
Standard Deviation: 8.24

Age, Categorical

Region of Enrollment

Sex: Female, Male

Overall Study

Standard Treatment


Drop/Withdrawal Reasons

Standard Treatment