Efficacy of belimumab in patients with SLE and haematological manifestations: retrospective analysis from the BeRLiSS 2.0 cohort

Objective To assess the effectiveness of belimumab (BEL) in improving anaemia, thrombocytopenia, lymphopenia and leucopenia in patients with SLE.Methods The BeRLiSS (Belimumab in Real Life Setting Study) 2.0 cohort included patients with SLE from 14 Italian referral centres treated with BEL for active joint or skin involvement, based on physician judgement, between June 2013 and May 2024. Clinical and laboratory parameters were recorded at baseline and every 6 months. Patients were eligible if they had baseline haematological abnormalities defined according to British Isles Lupus Assessment Group (BILAG) (grade C or higher): haemoglobin (Hb) ≤10.9 g/dL, platelets (Plts) ≤149×109/L, lymphocytes (Lym) ≤1.0×109/L or leucocytes (Leuc) ≤3.0×109/L. Follow-up data up to month 48 were available for 33 patients with anaemia, 20 with thrombocytopenia, 44 with lymphopenia and 18 with leucopenia.Results At baseline, 76 patients had anaemia, 44 thrombocytopenia, 107 lymphopenia and 53 leucopenia. Hb levels increased significantly from 9.9±0.6 g/dL to 11.7±1.4 g/dL at month 48 (p<0.001). Platelet counts rose from 110.2±38.1×109/L to 176.6±88.7×109/L (p=0.004), Lym counts from 0.72±0.21×109/L to 1.14±0.45×109/L (p<0.001) and leucocyte counts from 2.437±0.533×109/L to 4.732±1.897×109/L at 48 months (p<0.001). Improvement in Hb (p=0.97), Plts (p=0.12), Lym (p=0.86) and Leuc (p=0.73) was similar regardless of the use of concomitant immunosuppressants. Glucocorticoid (GC) doses decreased significantly across all manifestations, except for leucopenia: anaemia (12.9±12.1 to 3.6±4.9 mg/day, p=0.003), thrombocytopenia (10.8±9.6 to 4.4±5.5 mg/day, p=0.004), lymphopenia (10.6±8.6 to 3.1±3.2 mg/day, p<0.001). Proportion of GC users declined over 48 months: anaemia 96.1–60.7%, thrombocytopenia 93.1–80%, lymphopenia 96.3–70.3% and leucopenia 95.3–80%.Conclusion In this real-world cohort, BEL treatment was associated with improvement in anaemia, thrombocytopenia, lymphopenia and leucopenia with over half of patients achieving normalisation of blood counts. Haematological responses were similar regardless of concomitant immunosuppressive therapy, supporting the role of BEL as a therapeutic option for haematological abnormalities in SLE.