Hydroxychloroquine for Thrombosis Prevention and Antiphospholipid Antibody Reduction in Primary Antiphospholipid Syndrome

Patients with primary antiphospholipid syndrome (either thrombotic or obstetric) on regular follow-up at our outpatient rheumatology department and being treated with standard care (systemic anticoagulants and/or antiplatelet agents), are randomized to receive either hydroxychloroquine plus standard care, or standard care alone, on a 1:1 ratio using block size 2 randomization, after exclusion of patients with contraindications to hydroxychloroquine or prior hydroxychloroquine use within 12 months of consideration for enrollment. Patients are monitored clinically every 3 months and the development of thrombosis and/or adverse effects attributable to hydroxychloroquine is recorded. Antiphospholipid antibody titers (anti-cardiolipin immunoglobulin G (IgG)/Immunoglobulin M (IgM) and anti-beta2-glycoprotein I IgG/IgM isotypes) are measured semi-annually. Intention-to-treat survival analysis is applied for assessing the effect of hydroxychloroquine on the incidence of thrombosis. Longitudinal mixed linear models are applied for assessing the effect of hydroxychloroquine on longitudinal titers of antiphospholipid antibodies.

• Hydroxychloroquine (Drug), also known as Antimalarials, Plaquenil: Hydroxychloroquine 200 mg daily for patients weighing < 60 kg, hydroxychloroquine 400 mg daily for patients weighing >= 60 kg

Primary outcomes

• Incident acute thrombosis in the venous or arterial circulation [3 years]: incident acute arterial thrombosis (myocardial infarction, stroke, transient ischemic attack, occlusion of the peripheral limb and neck, splanchnic, or retinal arteries) or venous thrombosis (pulmonary embolism, deep vein thrombosis, splanchnic vein thrombosis, retinal vein occlusion) confirmed by appropriate imaging studies (doppler ultrasonography, computed tomography pulmonary angiogram, conventional angiography, magnetic resonance angiography, ventilation/perfusion lung scintigraphy)

Secondary outcomes

• Hydroxychloroquine-related safety outcomes [3 years]: * Retinal toxicity by ocular examination, visual field testing and optical coherence tomography yearly and upon reporting visual symptoms * Toxic myopathy: new onset motor strength <=4/5, myalgia and creatine kinase elevation * Liver toxicity: liver enzyme elevations >3x of upper limit of normal (ULN), or serum total bilirubin >2x ULN, with no cholestasis * Metabolism disorders (hypoglycemia, weight decrease) by quarterly body weight and blood glucose testing * Bone marrow suppression: drop in hemoglobin to < 10 mg/dl, white blood cells < 3700/μL, platelets < 150,000/μL according to a hematologist * Cardiac complications (conduction defects, QT prolongation, cardiomyopathy) screened by interview, physical examination, and semi-annual electrocardiogram * Seizures screened by interview and confirmed by electrocardiogram * Gastrointestinal upset, allergic reactions, skin reactions by interview and physical exam
• Anticoagulation treatment-related safety outcomes [3 years]: * Major bleeding, defined as fatal bleeding, or symptomatic bleeding in a critical area or organ, such as intracranial, intraspinal, intraocular, retroperitoneal, intra-articular or pericardial, or intramuscular with compartment syndrome, and/or bleeding causing a fall in hemoglobin level of 2 g/dL or more, or leading to transfusion of two or more units of whole blood or red cells. * Minor bleeding defined as clinically evident bleeding not fulfilling the definition of major bleeding
• General safety outcomes [3 years]: * Hospitalization for any cause * Death of any cause * APS-related death (based on death certificate records)

Other outcomes

• Antiphospholipid antibody titer variation [3 years]: Anticardiolipin IgG antibody titers, anti-cardiolipin IgM antibody titers, anti-beta2-glycoprotein I IgG antibody titers, antibeta2-glycoprotein I IgM antibody titers measured every 6 months.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

Adult patients diagnosed with primary antiphospholipid syndrome (PAPS) \[updated Sapporo criteria: Miyakis et al, J Thromb Haemost. 2006 Feb;4(2):295-306. PubMed 16420554\]

Exclusion Criteria:

1. ≥4 American College of Rheumatology (ACR) classification criteria for Systemic Lupus Erythematosus (SLE)
2. ACR classification criteria for other systemic autoimmune disorders
3. active malignancy
4. treatment with Hydroxychloroquine (HCQ) in the previous 12 months
5. history of serious adverse events or contraindication to HCQ including a history of HCQ allergy, HCQ eye toxicity, or glucose-6-phosphate dehydrogenase deficiency, uncontrolled seizure disorder, liver enzyme elevation >2-fold the upper normal limit, and creatinine clearance <30ml/min

• Maria G Tektonidou, MD PhD, Principal investigator, National and Kapodistrian University of Athens