0671: Thrombocytopenia and Autoimmune Hemolytic Anemia in Antiphospholipid Antibody-positive Patients: Descriptive Analysis of the AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) Clinical Database and Repository (“Registry”)

Zeynep Belce Erton¹, Rebecca K.Leaf², Danieli Castro Oliveira de Andrade³, Megan Barber⁴, Maria G. Tektonidou⁵, Vittorio Pengo⁶, Savino Sciascia⁷, Amaia Ugarte⁸, H Michael Belmont⁹, Chary López-Pedrera¹⁰, Paul R Fortin¹¹, maria gerosa¹², Guilherme de Jesús¹³, Tatsuya Atsumi¹⁴, ZHUOLI ZHANG¹⁵, Hannah Cohen¹⁶, D. Ware Branch¹⁷, Denis WAHL¹⁸, Laura Andreoli¹⁹, Esther Rodriguez Almaraz²⁰, Michelle Petri²¹, Ricard Cervera²², Yu (Ray) Zuo²³, Bahar Artim-Esen²⁴, ²⁵, Rohan Willis²⁶, Maria Laura Bertolaccini²⁷, Robert Roubey²⁸, Doruk Erkan¹ and on behalf of APS ACTION On Behalf Of APS ACTION¹, ¹Hospital for Special Surgery, New York, NY, ²Massachusetts General Hospital, Boston, MA, ³Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil, ⁴Cumming School of Medicine, University of Calgary, Calgary, AB, Canada, ⁵National and Kapodistrian University of Athens, Athens, Greece, ⁶Padova University Hospital, Padova, Italy, ⁷University of Turin, Torino, Italy, ⁸BioCruces Bizkaia Health Research Institute, Barakaldo, Spain, ⁹NYU School of Medicine, New York, NY, ¹⁰Maimonides Institute for Biomedical Research of Córdoba, Cordoba, Spain, ¹¹Centre ARThrite - CHU de Québec - Université Laval, Québec, QC, Canada, ¹²University of Milan, Milano, Italy, ¹³Universidade do Estado do Rio de Janeiro, Rio De Janeiro, Brazil, ¹⁴Hokkaido University, Sapporo, Japan, ¹⁵Peking University First Hospital, Beijing, China, ¹⁶University College London Hospitals NHS Foundation Trust, London, United Kingdom, ¹⁷University of Utah, Salt Lake City, UT, ¹⁸University of Lorraine, Nancy, France, ¹⁹Rheumatology and Clinical Immunology Unit, ASST Spedali Civili and University of Brescia, Brescia, Italy, ²⁰Hospital Universitario 12 de Octubre, Madrid, Spain, ²¹Johns Hopkins University School of Medicine, Division of Rheumatology, Baltimore, MD, ²²Hospital Clinic Barcelona, Barcelona, Spain, ²³University of Michigan, Ann Arbor, MI, ²⁴Istanbul University, Istanbul, Turkey, ²⁵Grupo Oroño - Centro Regional de Enfermedades Autoinmunes y Reumáticas (GO-CREAR), Rosario, Santa Fe, Argentina, ²⁶University of Texas Medical Branch, Galveston, TX, ²⁷King's College London, London, United Kingdom, ²⁸University of North Carolina, Chapel Hill, NC

Background/Purpose: The APS ACTION Registry was created to study the natural course of antiphospholipid syndrome (APS) over 10 years in persistently antiphospholipid antibody (aPL) positive patients with or without systemic autoimmune disease (SAIDx). Our primary objective was to compare the clinical characteristics of aPL-positive patients with or without thrombocytopenia (TP) and/or autoimmune hemolytic anemia (AIHA). Secondly, we compared the treatment strategies for TP and AIHA in aPL-positive patients with or without lupus.

Methods: An online database is used to collect clinical data. The registry inclusion criteria are positive aPL based on the laboratory section of the current APS Classification Criteria, tested at least twice within one year prior to enrollment. For the primary analysis, patients were divided into two groups: TP and/or AIHA ever; and no TP/AIHA ever, based on data collected at the registry recruitment. Thrombocytopenia was defined as a platelet count of < 100,000 per microliter tested twice at least 12 weeks apart, and AIHA was defined as anemia with hemolysis and with a positive direct antiglobulin test (DAT). For the secondary analysis, patients with TP and/or AIHA were divided into two groups: primary aPL/APS vs those with lupus classification. Data on demographics, clinical, serologic, and treatment characteristics were compared by using Fisher’s exact test.

Results: As of April 2022, 1,039 patients (primary aPL/APS: 618 [16%]; lupus classification: 334 [31%]) were included in the registry; 228 (22%) were reported to have TP and/or AIHA (TP: 193 (85%) [58 active and 135 historical]; AIHA: 52 (23%) [14 active and 38 historical], and both: 17 (7%) at baseline. Of 228, 101 (44%) had primary aPL/APS and 102 (45%) had lupus classification. The mean baseline platelet count was 78,000/uL (+ 26.5) in active TP patients (range: 3.000-99.000/uL). Based on the primary analysis, TP and/or AIHA was significantly associated with aPL-related microvascular (diffuse alveolar hemorrhage, aPL-nephropathy, livedo, and livedoid vasculopathy related skin ulcers) and/or cardiac valve disease, lupus anticoagulant (LA) and triple aPL positivity, and lupus classification (positive ANA, anti-dsDNA, and anti-Sm positivity, and low C3/C4 levels were significantly more common in patients with TP and/or AIHA) (Table 1). When 101/618 (16%) primary aPL/APS patients and 101/334 [34%] SLE patients with TP and/or AIHA were compared, azathioprine (AZT), mycophenolate mofetil (MMF), and methotrexate (MTX) use were more commonly reported in lupus patients, however corticosteroid, hydroxychloroquine, intravenous immunoglobulin, or rituximab use was similar between groups (data not shown).

Conclusion: In our large multi-center international cohort of persistently aPL-positive patients, one-fifth had active or historical TP and/or AIHA at the registry entry; half of these patients had additional lupus classification. Microvascular APS and/or cardiac valve disease as well as LA or triple aPL-positivity were associated with TP and/or AIHA, suggesting a more severe APS clinical phenotype in aPL-patients with TP and/or AIHA.

Disclosures: Z. Erton, None; R. K.Leaf, None; D. Castro Oliveira de Andrade, None; M. Barber, Sanofi-Genzyme, AbbVie/Abbott, GlaxoSmithKlein(GSK), AstraZeneca, Janssen; M. Tektonidou, None; V. Pengo, None; S. Sciascia, None; A. Ugarte, None; H. Belmont, None; C. López-Pedrera, None; P. Fortin, AstraZeneca, GlaxoSmithKlein(GSK); m. gerosa, None; G. de Jesús, None; T. Atsumi, Alexion, Chugai Pharmaceutical, Daiichi Sankyo, Mitsubishi Tanabe Pharma, Otsuka Pharmaceutical, Pfizer, Teijin Pharma, AbbVie, Bristol-Myers Squibb (BMS), Eisai, Eli Lilly Japan, Kyowa Kirin, Novartis, Taiho Pharmaceutical, Takeda Pharmaceutical, UCB Pharma, AstraZeneca, Medical and Biological Laboratories, Boehringer-Ingelheim, Ono Pharmaceutical, Gilead Sciences, Inc., Astellas Pharma; Z. ZHANG, None; H. Cohen, None; D. Branch, None; D. WAHL, None; L. Andreoli, GlaxoSmithKlein(GSK), Janssen, Novartis, UCB, Werfen; E. Rodriguez Almaraz, None; M. Petri, Exagen, AstraZeneca, Alexion, Amgen, AnaptysBio, Argenx, Aurinia, Biogen, Caribou Biosciences, CVS Health, EMD Serono, Eli Lilly, Emergent Biosolutions, GlaxoSmithKline (GSK), IQVIA, Janssen, Kira Pharmaceuticals, MedShr, Sanofi, SinoMab, Thermofisher, BPR Scientific Advisory Committee; R. Cervera, None; Y. Zuo, None; B. Artim-Esen, None; . , None; R. Willis, None; M. Bertolaccini, UCB Biopharma SRL; R. Roubey, None; D. Erkan, None; o. On Behalf Of APS ACTION, None.