[Hydroxychloroquine to obtain pregnancy without adverse obstetrical events in primary antiphospholipid syndrome: French phase II multicenter randomized trial, HYDROSAPL].

Antiphospholipid syndrome is defined by the presence of thrombosis and/or obstetrical adverse events (≥3 recurrent early miscarriage or fetal death or a prematurity<34 weeks of gestation) associated with persistent antiphospholipid antibodies. The pregnancy outcome has been improved by the conventional treatment (aspirin 100mg/day with low molecular weight heparin [LMWH] from 30 to 75% of uncomplicated pregnancies. In PROMISSE study, 19% of pregnancies had at least one obstetrical adverse event despite treatment (maternal, fetal or neonatal complications) in relation with APS. In the European registry of babies born from APS mothers, maternal and foetal adverse events were observed in 13% of cases, with prematurity in 14% despite treatment. The presence of lupus erythematosus, a history of thrombosis, presence of lupus anticoagulant and APL triple positivity are considered as factors associated with unfavorable obstetrical outcome. Hydroxychloroquine (HCQ) has anti-inflammatory and anti-thrombotic properties. Studies in vitro have shown that HCQ is able to restore the placental expression of Annexin V, which has an anticoagulant effect and to prevent the placental injury induced by APL. HCQ used for lupus erythematosus decrease the thrombotic risk and its value for thrombotic APS has been raised in an open labelled French study. In European retrospective study, the addition of HCQ to conventional treatment improved refractory obstetrical APS. Its use during the pregnancy of patients with lupus erythematosus, the evidence of good safety during the pregnancy and follow-up of children born to mothers exposed to HCQ demonstrate an overall good safety profile for mothers and the fetus. This clinical trial is designed to assess the interest of the addition of hydroxychloroquine to conventional treatment in APS during the pregnancy.