BASELINE PROFILE OF SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS ON TREATMENT WITH BELIMUMAB OF A SPANISH MULTICENTER COHORT

I. Altabás González, J. M. Pego-Reigosa, A. Hernández-Martín, J. Font, I. Casafont-Solé, J. A. Román Ivorra, M. DE LA Rubia Navarro, M. Galindo, T. C. Salman Monte, J. Narváez, P. Vidal Montal, M. J. Garcia Villanueva, C. Marras Fernandez Cid, M. M. Piqueras Garcia, J. Martínez-Barrio, M. Sánchez Lucas, J. Cortés-Hernández, E. Penzo, J. Calvo-Alén, J. R. De Dios, E. Tomero Muriel, R. Menor-Almagro, M. Gandia Martinez, J. A. Gómez-Puerta, B. Frade-Sosa, C. Ramos Giráldez, C. Trapero, A. Muñoz Jimenez, C. Moriano, E. Diez Alvarez, N. Jiménez, I. Rua-FigueroaComplejo Hospitalario Universitario de Vigo, Rheumatology, Vigo, Spain IRIDIS Group, IISGS, Vigo, Spain Hospital Universitario de Gran Canaria Dr. Negrín, Rheumatology, Las Palmas de Gran Canaria, Spain Hospital Universitario Germans Trias i Pujol, Rheumatology, Badalona, Spain Hospital Universitario y Politécnico de la Fe, Rheumatology, Valencia, Spain Hospital 12 de octubre, Rheumatology, Madrid, Spain Hospital del Mar, Rheumatology, Barcelona, Spain Hospital Universitario de Bellvitge, Rheumatology, Barcelona, Spain Hospital Universitario Ramón y Cajal, rheumatology, madrid, Spain Hospital Virgen de la Arrixaca de Murcia, Rheumatology, Murcia, Spain Hospital General Universitario Gregorio Marañón, Rheumatology, Madrid, Spain Hospital Universitario Valle de Hebrón, Rheumatology, Barcelona, Spain Hospital Universitario Araba, Rheumatology, Vitoria, Spain Hospital Universitario de La Princesa, Rheumatology, Madrid, Spain Hospital Universitario de Jerez, Rheumatology, Cádiz, Spain Hospital Clinic de Barcelona, Rheumatology, Barcelona, Spain Hospital Universitario Nuestra Señora de Valme, Rheumatology, Sevilla, Spain Hospital Universitario Virgen del Rocío, Rheumatology, Sevilla, Spain Hospital Universitario de León, Rheumatology, León, Spain  Background Belimumab (BLM) is a recombinant human IgG-1λ monoclonal antibody that inhibits B-cell activating factor. It is commonly used for treatment of systemic lupus erythematosus (SLE) patients with inadequate control to first-line treatments and inability to taper GC daily dose to acceptable levels. More recently it has been approved for patients with active lupus nephritis. Objectives To report baseline profile of SLE patients treated with BLM enrolled in a SLE Spanish registry. Methods Multicenter retrospective and longitudinal cohort study including SLE patients treated with BLM in 18 Spanish rheumatology units. Demographic, clinical data and treatments were collected at baseline, 6, 12 months and in the last visit available. Patients starting BLM in different periods (2010-2015 and 2016-2021) were compared regarding the reason of prescription of the drug. Results 324 patients (91% female, 84,8% caucasian) were enrolled. Mean (±SD) age at diagnosis: 31.8 years (±11.9); mean disease duration of 8.7 years (±9.07) and mean follow-up 3.8 (±2.7). A total of 319 (98.45%) subjects met SLE 1997 ACR or SLICC 2012 criteria; 217 (68.2%) were anti-dsDNA positive and 224 (69.8%) had low complement levels. At baseline, the mean SLEDAI-2K score was 10.4 (±5.25); 152 (47.5%) of patients had damage with a mean SDI score of 0.83 (±1.2). A total of 289 patients (89.2%) had received disease modifying anti-rheumatic drugs (DMARDs) before BLM: conventional (cDMARDS) in 282 patients (87%) and biologic DMARDs (bDMARDs) in 74 patients (22.8%); 164 (51.9%) had received more than one cDMARDs, methotrexate being the most frequently used (44.4%). Other cDMARDs used were: mycophenolate mofetil in 104 (37.01%), azathioprine in 91 (32.38%), leflunomide in 29 (10.32%), cyclophosphamide in 28 (9.92%) and calcineurin inhibitors in 13 (4.6%) of patients. The most frequent bDMARDs used was Rituximab in 80%. Most patients were receiving antimalarials (83,2%) and glucocorticoids (GC) (91.2%), with a mean dose of 12.3 mg/day. A total of 209 (67.9%) patients were receiving more than 5 mg/day and 180 (58.4%) more than 7.5 mg/day of prednisone. BLM was used in monotherapy in 99 (30.5%) subjects. It was initiated due to disease activity in 307 patients (95%) and/or as a GC sparing agent in 191 patients (59%). Most patients initiated BLM for several concurrent reason; only a few patients received BLM just for maintenance (4/322) or save GC (8/322). At baseline, only 6 patients (1.9%) were in DORIS-21-remission and LLDAS. The main reasons of prescription for ongoing activity were arthritis (65.4%), cutaneous (40.7 %) or both (81%). There were no statistically significant differences in any of the prescription reasons when comparing the periods 2010-2015 and 2016-2021. Table 1. Type and reasons of prescription of Belimumab N (%) or mean (± SD) (n = 324 patients) Age at prescription of Belimumab (years) 42.3 (± 12.9) Intravenous Belimumab 215 (66.35%) Subcutaneous Belimumab 110 (33%) Reasons of prescription* (multiple response allowed) Disease activity 307 (95%) Maintenance 197 (61%) Glucocorticoid sparing 191 (59 %) Activity Cutaneous 132 (40.7 %) Articular 212 (65.4%) Renal 58 (17,9%) Hematological 60 (18.5%) Serosal 47 (14.5%) Other 29 (8.82%) Conclusion In the majority of patients, belimumab was prescribed after the use of other DMARDs and more than 50% of patients had received at least 2 DMARDs and were receiving GC at medium doses. One third of patients received BLM as monotherapy. It was prescribed due to active disease in the vast majority of patients and/or as GC sparing agent. Activity in articular and cutaneous domains were the main reasons of indication. No changes in prescription habits were identified over time. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests None Declared. Keywords: bDMARD, Systemic lupus erythematosus, Descriptive Studies DOI: 10.1136/annrheumdis-2023-eular.3003Citation: , volume 82, supplement 1, year 2023, page 1461Session: SLE, Sjön’s and APS - treatment (Publication only)