Efficay and safety of belimumab in lupus patients with hematological involvement in a multicenter prospective cohort study

Systemic Lupus Erythematosus (SLE) is an autoimmune disease characterized by a disfunction of the immune system and widespread inflammation. One common manifestation of SLE is hematological involvement. Lymphopenia, especially, is related to high disease activity and difficult prognosis. This study aims to assess the efficacy and safety of Belimumab, a monoclonal antibody that binds the B Lymphocyte Stimulator (BlyS), in SLE patients manifesting hematological involvement across two cohorts. In the first part of the study, 107 patients manifesting lymphopenia, enrolled in the BeRLiSS cohort, were considered. Lymphocyte count, complement levels, prednisone dosage, and disease activity indicators were taken into consideration to evaluate the general hematological response and disease activity over time. Belimumab efficacy in lymphopenic-at baseline patients was assessed by lymphocyte counts evaluated at 6, 12, 24, 36, and 48 months. The second study involves thirteen patients from the Padua Lupus Clinic (Division of Rheumatology, University of Padua, Italy), with the objective of extending the evaluation of Belimumab’s safety to a second cohort with a longer follow-up period to assess the long-term effects. A total of 107 patients from the BeRLiSS cohort, of which 88.8% were females, with a disease duration of 11.27 ±8.42 years pre-belimumab were considered. Over a treatment period of 31.1±16.3 months, we observed a significant improvement in lymphocyte count (baseline 720±208.75, 6 months 778±325, 12 months 910.17±436.43, 24 months 1042±570, 36 months 1098.78±557.82, 48 months 1144±447, p<0.001). In addition, prednisone doses were significantly reduced by the final follow-up (PDN at baseline 10.63±8.59, 6 months 6.27±4.7, 12 months 6.29±6.29, 24 months 4.25±4.19, 36 months 3.79±3.91, 48 months 3.13±3.16, p<0.001). In the second cohort, including patients with longer treatment with belimumab, we confirmed the efficacy and the safety in the long-term, as we did not observe any increase in infections or other adverse events. These outcomes accentuate the potential of Belimumab as a safe and efficient treatment strategy for SLE patients manifesting lymphopenia as hematological involvement.