Background: Lupus nephritis (LN) remaining as one of the most devastating manifestations of systemic lupus erythematosus (SLE). Only 60% of patients with LN achieve a complete (CR) or partial remission (PR) with mycophenolate mofetil (MMF) or intravenous (iv) cyclophosphamide (CY) plus corticosteroids. Of those nearly one-half will have a relapse following maintenance therapy [1]. Rituximab (RTX) is considered a treatment of relapsing LN [2]. Although potential benefits have been revealed in descriptive studies, efficacy has not been established in randomized trials [3,4].

Objectives: This study compares the efficacy achieving a CR or PR with MMF+RTX versus iv CY+RTX in patients with relapsing LN.

Methods: Mexican SLE patients classified by SLICC 2012 criteria were recruited from 2013 to 2019 with LN diagnosed by renal biopsy who previously having achieved a CR with MMF or iv CY followed by the maintenance therapy with azathioprine (AZA) or MMF and subsequently present relapsing LN consisting of a new active urinary sediment (US), worsening proteinuria and renal function. Demographic, renal clinical and paraclinical variables were examined. All patients received oral prednisone (1 mg/kg/d) accompanying MMF 3 g/d or CY 0.5–1 g/m ² monthly plus RTX 1 g at 0 and 14 days. The data were evaluated at 0, 6, 12 and 24 month(s) after the start both treatments. CR was defined as normal serum creatinine (SCr), inactive US, plus 24-Hour Urine Protein (24hUP) <500 mg/d and PC was established as 50 percent improvement in renal parameters. Fisher’s exact and Student´s-t tests were performed by univariate analysis.

Results: Of nine SLE patients with relapsing LN, seven were women. The mean age [standard deviation (SD)] was 25.1 (6.4) years. The mean time at the onset of SLE (SD) was 3.44 (1.12) years ago. Four and five patients had class IV and IV/V LN respectively. Time of relapsing LN after of CR (SD) was 21.2 (7.17) months. Seven patients used CY followed by AZA and two employed MMF previously of relapsing LN. The mean of basal SLEDAI and SLICC (SD) were 19.11(3.2) and 1.22 (0.44) respectively. The mean of basal 24hUP (SD) was 4.67 (2.6) g/d and sCr (SD) was 2.0 (0.84) mg/dl. Five patients used MMF+RTX and four patients utilized CY+RTX. No statistically significant differences were found for CR, PR, 24hUP, sCr, US, anti-dsDNA and complement between both groups. At 6 months one patient achieved a CR and six reached a PR. At 12 months four patients fulfilled a CR and seven had a PR. Finally, at 24 months seven patients showed a CR and a CP. Only two patients did not achieve a CR or PR at 24 months.

Conclusion: This study suggests that the most of SLE patients with relapsing LN treated with CY or MMF plus RTX achieved CR or PR at 24 months, although were no found differences between both treatments. However, these observations must be confirmed in larger and prospective studies.

REFERENCES:

[1]Ann Rheum Dis 2020;79(6):713;

[2]Nephrol Dial Transplant 2019;34(1):22;

[3]Clin J Am Soc Nephrol 2009;4(3):579;

[4]Arthritis Rheum 2012;64(4):1215

Disclosure of Interests: None declared