MO163: Mycophenolate Mofetil Superior to Azathioprine and as Effective as Calcineurin Inhibitors in Lupus Nephritis Maintenance Therapy: Data from a Single Centre Prospective Study
Authors: Mirela Stroie Anna , Penescu Mircea , Paul Balanescu 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Systemic lupus erythematosus is the prototype of a multiorgan, multisystemic autoimmune disease. It has relatively frequent renal involvement (prevalence of 15–60%). A total of 19–25 patients develop end-stage renal disease after 10 years of disease onset. We studied the efficiency of mycophenolate mofetil compared to azathioprine and calcineurin inhibitors as maintenance therapy. We analysed a population of 67 patients with biopsy-proven lupus nephritis. We compared the groups for rates of achievement and maintaining remission at 18 months after the induction therapy, renal flares and rates of ESRD at the end of the study.

METHOD
We concluded a single-centre longitudinal study to assess the efficacy of mycophenolate mofetil as maintenance therapy in patients with biopsy-proven lupus nephritis: clinical remission rates, renal flares, renal function at the end of the follow-up period. We used SPSS version 16 for the statistics. Clinical data were taken from the electronic health records of the hospital (Hipocrate Informational System).

RESULTS
We included in the study patients diagnosed with systemic lupus erythematosus, who underwent renal biopsy between January 2008 and December 2018, followed-up until May 2020. Patients were assessed using proteinuria, anti-DNA double-strand antibodies, serum creatinine and eGFR-CKD-EPI measurements, C3, C4 levels and urinary sediment. In our study group, 58 patients were female, 9 were male, with a median age at diagnosis of 29 years, and median duration of the disease of 10 years. Median duration of corticosteroid treatment was 10.1 years. The most frequent classes of lupus nephritis were class IV (47.76%), class III (17.91%) and class V (17.91%) (ISN classification). At the moment of the kidney biopsy, 77.61% patients had nephrotic syndrome, and 22.39% nephritic syndrome. Patients underwent induction therapy with standard regimens (NIH 55.22%, Euro-Lupus 19.4%, mycophenolate 25.37%, CNI 1.49%). Maintenance therapy during the study period was as follows (all patients had corticosteroids in standard dose): 5 had mycophenolate, 27 azathioprine, 26 had both mycophenolate and azathioprine during the study period (treatment switches form one immunosuppressant to another were necessary during the study period due to adverse effects, occurring pregnancies, patient preference, costs of treatment), and 9 had calcineurin inhibitors. Of the 67 patients, at 18 months after the first induction regimen, 3 had no therapeutic response, and required a second course of induction, 25 maintained partial remission and 39 maintained total remission. A total of 21/67 patients had no renal flare, 46/67 patients had renal flares. At the end of the study, 13/67 patients were ESRD and 54/67 were non-ESRD. We obtained the following results (Kruskal–Wallis and Bonferroni tests): maintaining remission at 18 months following induction therapy for mycophenolate mofetil—15.4% complete remission, 2.6% partial remission; in the azathioprine group—52.6% partial remission, 26.9% complete remission; in patients who received both mycophenolate and azathioprine (required a switch in therapy)—36.8% partial remission, 42.3% complete remission; in patients receiving calcineurin inhibitors—7.9% partial remission, 15.4% complete remission (P = .02). Renal flare rates were 7.1% for calcineurin inhibitors, 11.9% for mycophenolate mofetil, 28.6% for azathioprine, 52.4% for azathioprine and mycophenolate (Kruskal–Wallis, P = .002). At the end of the study, the frequency of ESRD was lowest in patients receiving mycophenolate or calcineurin inhibitors: 7.1% mycophenolate, 7.1% calcineurin inhibitors, 14.3% azathioprine, 71.4% mycophenolate and azathioprine (P = .039).

CONCLUSION
We identified that mycophenolate mofetil therapy led to better renal outcomes compared to azathioprine (higher clinical remission rates and fewer ESRD patients) and proved the same efficiency as calcineurin inhibitors.