ADMINISTRATION OF BELIMUMAB IN EARLY ACTIVE LUPUS PATIENTS HINDERS ACCRUAL OF EULAR/ACR CRITERIA WITHIN THE FIRST 12 MONTHS OF TREATMENT

O054 / #505 Topic: AS24 - SLE-Treatment ABSTRACT CONCURRENT SESSION 09: SLE THERAPY – REVISITING OLD DRUGS AND UNLOCKING HIDDEN POTENTIAL OF NEW MEDICATIONS 24-05-2025 10:40 AM - 11:40 AM Background/Purpose Addition of biologic drugs to standard of care (SoC) in systemic lupus erythematosus (SLE) is advised in refractory patients. Evidence is needed on the effectiveness of early biologic use in influencing SLE course. In this cohort study, we aim to assess the effect of belimumab administration on disease progression in early active lupus patients. Methods We performed a multicentric observational study on patients with early SLE receiving either belimumab or SoC alone and compared the rate of EULAR/ACR 2019 criteria accrual between the 2 groups as a measure of lupus progression over time. Patients were defined as early active if they were diagnosed within 12 months from treatment initiation and displayed up to 2 EULAR/ACR clinical criteria, excluding major organ involvement, with active serology (ie, positive anti-dsDNA antibodies and/or decreased serum complement). Clinical, demographic and serological data were collected in an anonymized fashion at baseline and at 3, 6, and 12 months. Kaplan-Meier curves with log-rank comparison were used to assess criteria accrual throughout the first 12 month of follow-up. Results We included 57 early active SLE patients, 24 (42.1%) receiving SoC alone and 33 (57.9%) receiving add on belimumab to SoC and followed up for at least 12 months from baseline. The groups were comparable in terms of age, gender, disease duration, background immunosuppression and overall disease activity at baseline. Patients doomed to early belimumab displayed higher mean SLICC and prednisone daily dosage (Table 1). Overall, 8.7 events/100-patients years occurred in our cohort. Twenty-five percent of patients on SoC vs 3.2% of patients on early belimumab accrued at least one EULAR/ACR criterion throughout the follow-up (p=0.035). Patients on SoC displayed development of skin rash (2 cases), arthritis (1 case), lupus nephritis (1 case), while one case of pericarditis occurred in the belimumab group. Criteria-free survival was significantly longer in patients receiving belimumab early as compared to those receiving SoC alone (log-rank 5.78, p=0.016) (Figure 1). Mean time-to-event (months) was shorter in patients on SoC alone (10.3± 3.33 vs. 11.8±1.07, p=0.027). Table 1. Baseline clinical and demographic features of early SLE patients Figure 1. Kaplan-Meier curves depicting criteria-free survival in patient groups Continuous variables expressed as mean±SD. HCQ, hydroxycholoroquine; IS, immunosuppressants; cSLEDAI-2K, clinical SLE-activity index 2000; SLICC-DI, SLICC damage index Conclusions Timely use of belimumab in patients with early active SLE can significantly delay disease progression, potentially preventing development of severe manifestations.