Background B cells are critically involved in the pathogenesis of systemic lupus erythematosus (SLE), and their increased activity is driven in part by increased levels of growth factors, including B-lymphocyte stimulator (BLyS). Belimumab inhibits activity of BLyS, effectively and safely treats SLE, but data on treatment cessation are lacking. Therefore, we investigated belimumab-free remission in SLE patients.

Methods SLE patients receiving belimumab in our institute (1/1/2013–5/31/2019) were retrospectively identified using electronic health records. Eligibility criteria were receiving belimumab for >180 days and discontinuation for any reason. BILAG category A or B in at least one organ system defined disease flares. Follow-up monitoring after 52 weeks post-treatment identified relapse-free and relapse patients.

Results 31 patients received belimumab. While 14 patients discontinued, eight were included. Four patients relapsed within 52 weeks. Relapse-free patients received significantly less steroid at discontinuation (prednisolone equivalent, median 3.0 mg/day [IQR 2.75–3.19] vs. 9.5 mg/day [IQR 7.25–13.25], p=0.02), and significantly more of them achieved PSL dosage of <5 mg/day on discontinuation day than relapse patients. (p=0.03) At belimumab discontinuation, relapse-free patients tended to have higher C3 (median 91.0 mg/dL [IQR 78.75–102.25] vs. 56.0 mg/dL [IQR 39.75–73.00], p=0.15) and C4 levels (median 22.0 mg/dL [IQR 19.00–26.00] vs. 11.0 mg/dL [IQR 6.00–16.00], p=0.08) and less anti-DNA antibody (median 5.2 IU/mL [IQR 3.75–7.83] vs. 48.0 IU/mL [IQR 11.50–137.25I], p=0.08) than relapse patients, but differences were not significant.

Conclusion Belimumab discontinuation after >180 days is recommended for 50% of SLE patients. Steroid dosage (prednisolone equivalent <5 mg/day) might be a prognostic marker for belimumab-free remission.

Funding The authors received no financial support for the research, authorship, and/or publication of this article.