FRI0186 HYDROXYCHLOROQUINE ON THE TOP OF STANDARD TREATMENT WITH LOW DOSE ASPIRIN AND LOW MOLECULAR WEIGHT HEPARIN SIGNIFICANTLY REDUCES THE PROBABILITY OF PREGNANCY MORBIDITY IN WOMEN WITH MULTIPLE POSITIVITY FOR ANTI-PHOSPHOLIPID ANTIBODIES

Background: Hydroxychloroquine is an anti-malarial drug that not only exerts immunomodulatory and anti-thrombotic properties, but also has been shown to reverse several effects mediated by anti-phospholipid antibodies (aPL) in models of obstetric anti-phospholipid syndrome (APS). Not surprisingly, HCQ, whose prescription during gestation is perfectly safe, has been proposed as an additional therapeutic tool in obstetric APS, but evidence of ist efficacy is still scant. Objectives: This study investigates how treatment with HCQ, prescribed in different combinations with low-dose aspirin (LDASA) and low-molecular weight heparin (LMWH), affects the probability of pregnancy morbidity (PPM). Methods: Data on pregnancies in women with persistent aPL positivity at any titre, with or without autoimmune diseases, were retrospectively collected at a single centre. A weigthed generalized estimated equation (GEE) model was applied to quantify the effect of treatment with HCQ on PPM, allowing to: i) evaluate pregnancy outcomes over time using available longitudinal data; ii) account that pregnancies of the same woman are not independent events; iii) consider that women had a different number of pregnancies; iv) estimate the role of several confounders and predictors. The model envisaged as dependent variable pregnancy outcome as a binary outcome, defined for each pregnancy as “obstetric complication yes versus no” (pregnancy loss before 10 weeks, pregnancy loss after 10 weeks, premature birth before 34 weeks, according to updated APS classification criteria). Results: Three-hundred-eighty-one women were recruited in this study: 155 women with aPL positivity (100 women with positivity for criteria aPL and 55 women with low titer aPL) and 226 women with autoimmune diseases but negative aPL. Data were collected on 847 pregnancies: 458 in women with positive aPL (172 in women with criteria aPL and 286 in women with low titer aPL) and 389 in women with autoimmune disease and negative aPL. PPM in untreated patients are presented in Table 1. Table 2 reports PPM in women receiving LDASA+/- HCQ, LDASA + LMWH +/- HCQ. Conclusion: HCQ, when added to LDASA or on the top of standard treatment with LDASA and LMWH, allows to reduce PPM. Most importantly, HCQ plus the combo LMWH + LDASA leads to a significantly reduction of PPM even in women at highest risk, namely those with multiple criteria aPL positivity. References: [1] Miyakis S, et al. J Thromb Haemost. 2006;4(2):295-306 [2] Sciascia S, et al. Thromb Haemost. 2016;115(2):285-90. [3] Ruffatti A, et al. Thromb Haemost. 2018;118(4):639-646. Disclosure of Interests: Cecilia Chighizola Speakers bureau: Inova Diagnostics, Francesca Pregnolato: None declared, Francesca Bartoli: None declared, Maria Gerosa: None declared, Chiara Comerio: None declared, Maria Gabriella Raimondi: None declared, Laura Trespidi: None declared, Maria Orietta Borghi: None declared, Manuela Wally Ossola: None declared, Enrico Ferrazzi: None declared, Pier Luigi Meroni Consultant for: Inova, Thermofisher, Teofarma