Sirolimus versus mycophenolate mofetil for the treatment of lupus nephritis: Results from a real-world CSTAR cohort study.

Background and objectives: No prior studies have directly compared sirolimus with the standard of care (SoC) for lupus nephritis (LN) patients. This study aimed to compare the efficacy and safety of sirolimus with mycophenolate mofetil (MMF) for the treatment of LN.

Methods: A real-world cohort study based on the Chinese SLE Treatment and Research (CSTAR) registry was conducted. Patients with active LN who were prescribed either sirolimus or MMF were enrolled. Propensity score matching was applied to ensure comparable baseline disease conditions. SLE disease activity indices, serological parameters, steroid doses, renal efficacy, and adverse events were evaluated at 3-month, 6-month, and 12-month follow-ups.

Results: Data from 53 patients in each group were analyzed. Sirolimus demonstrated clinical effectiveness comparable to MMF, as evidenced by similar rates of lupus nephritis remission and lupus low disease activity state (LLDAS) /remission or a clinical response (reduction of SLE Disease Activity Index 2000 [SLEDAI-2K] ≥4 and increase in physician's global assessment [PhGA] < 0.3), as well as changes in 24-hour urine protein level, SLEDAI-2K score, PhGA score, and steroid tapering effect (P ≥ 0.05 at all follow-up timepoints). Notably, sirolimus group exhibited greater improvements in complement levels compared to MMF group at 3, 6, and 12 months. Ten adverse events in sirolimus group and one in MMF group were reported, with no severe adverse events.

Conclusion: Sirolimus demonstrated comparable efficacy to MMF in the treatment of LN and glucocorticoid tapering, with additional benefits in serological improvement. Furthermore, sirolimus was well tolerated in LN patients, supporting its potential as a therapeutic option for LN.