Effectiveness and Safety of Belimumab in Chinese Lupus Patients: A Multicenter, Real-World Observational Study

Objective: The effectiveness and safety of belimumab in Chinese lupus patients with different disease activities were investigated in a real-world setting. Method: Patients who received 10 mg/kg belimumab intravenously on weeks 0, 2, and 4, and then every 4 weeks on a background of standard-of-care (SoC) therapy and had a follow-up of more than 6 months were enrolled from four centers in China. They were stratified according to the Safety of Estrogens in Lupus Erythematosus National Assessment-SLE Disease Activity Index (SELENA-SLEDAI) score at baseline as the moderate/severe (SELENA-SLEDAI > 6) or mild subgroups (SELENA-SLEDAI ≤ 6). Attainment of the Lupus Low Disease Activity State (LLDAS) or remission on treatment was analyzed in all patients. The SLE Responder Index 4 (SRI-4) and SELENA-SLEDAI Flare Index (SFI) were evaluated for patients with moderate/severe disease and mild disease, respectively. Patients in the control arm with SoC alone from previous metformin lupus trials were selected by propensity score matching (PSM) as the reference group. Results: 224 SLE patients with a mean follow-up of 11.7 months receiving belimumab were enrolled in this observational study, of which 126 and 98 were in the moderate/severe and mild subgroup, respectively. At 12 months, 54.76% of the patients attained LLDAS and 28.57% attained remission. Lower daily prednisone at baseline were independently associated with 12-month LLDAS. Further, 87% of the subgroup with moderate/severe disease achieved SRI-4 at 12 months and a high SLEDAI at baseline was its predictive factor. For the mild subgroup, a reduced flare rate was observed compared with PSM reference (17.5%, vs. 38.6%, p = 0.021). Infection events, particularly viral infections and pneumonia were recorded in 7 and 6 patients, respectively. Conclusion: Our real-world data supported the effectiveness and safety of belimumab in Chinese lupus patients.