2447: Longitudinal Disease Activity Trajectories in Patients with Systemic Lupus Erythematosus Treated with Belimumab

Background/Purpose: To investigate the longitudinal disease activity trajectories in patients with systemic lupus erythematosus (SLE) treated with belimumab.

Methods: A prospective cohort of SLE treated with belimumab was established, with record assessments every 3 months after baseline and every 6 months after 12 months of belimumab infusion. Patients' baseline clinical data, SLE disease assessment data, and treatment regimens were collected, and latent class trajectory modeling was used to identify the trajectory of change in patients' SLE Disease Activity Index 2000 (SLEDAI-2K) scores during the follow-up period and multinomial logistic regression analyses were used to assess the baseline clinical characteristics associated with each group.

Results: A total of 169 patients with SLE with belimumab were enrolled in the study, including 155 females (91.7%). The median age of patients at baseline was 34 years, and the median duration of SLE was 7 years. The baseline SLEDAI score of the enrolled patients was 7.8±5.1. Three different SLEDAI-2K score change trajectories were identified through trajectory modeling: 24.3% in the rapid improvement group, 71.0% in the slow improvement group, and 4.7% in the disease fluctuation group. Of the three groups, patients in the disease fluctuating group were more likely to have renal involvement (P=0.012) and had the highest baseline urinary protein quantification (P=0.000), compared to the slow improvement group, and patients in the slow improvement group had the lowest baseline prednisone dose of the three groups (P=0.000). Using multinomial logistic regression analysis, it was found that SSA antibody positivity was more closely associated with patients in the slow improvement group (OR 25.738, P=0.041) or the rapid improvement group (OR 33.679, P=0.026) compared to patients in the fluctuating group.

Conclusion: SLEDAI-2K changes in SLE patients treated with belimumab can be divided into three different response trajectory groups: the rapid improvement group, the disease fluctuating group, and the slow improvement group. Early initiation of belimumab in patients with active SLE may enhance their therapeutic response and improve their prognosis. In patients with lupus nephritis, regular follow-up can help detect disease recurrence at an early stage and reduce the overall risk of disease damage.