Mycophenolate Mofetil in Combination with Steroids for Treatment of C3 Glomerulopathy: A Case Series

Abstract

Background and objectives: C3 glomerulopathy is a form of complement-mediated GN. Immunosuppressive therapy may be beneficial in the treatment of C3 glomerulopathy. Mycophenolate mofetil is an attractive treatment option given its role in the treatment of other complement-mediated diseases and the results of the Spanish Group for the Study of Glomerular Diseases C3 Study. Here, we study the outcomes of patients with C3 glomerulopathy treated with steroids and mycophenolate mofetil.

Design, setting, participants, & measurements: We conducted a retrospective chart review of patients in the C3 glomerulopathy registry at Columbia University and identified patients treated with mycophenolate mofetil for at least 3 months and follow-up for at least 1 year. We studied clinical, histologic, and genetic data for the whole group and compared data for those who achieved complete or partial remission (responders) with those who did not achieve remission (nonresponders). We compared remission with mycophenolate mofetil with remission with other immunosuppressive regimens.

Results: We identified 30 patients who met inclusion criteria. Median age was 25 years old (interquartile range, 18-36), median creatinine was 1.07 mg/dl (interquartile range, 0.79-1.69), and median proteinuria was 3200 mg/g creatinine (interquartile range, 1720-6759). The median follow-up time was 32 months (interquartile range, 21-68). Twenty (67%) patients were classified as responders. There were no significant differences in baseline characteristics between responders and nonresponders, although initial proteinuria was lower (median 2468 mg/g creatinine) in responders compared with nonresponders (median 5000 mg/g creatinine) and soluble membrane attack complex levels were higher in responders compared with nonresponders. For those tapered off mycophenolate mofetil, relapse rate was 50%. Genome-wide analysis on complement genes was done, and in 12 patients, we found 18 variants predicted to be damaging. None of these variants were previously reported to be pathogenic. Mycophenolate mofetil with steroids outperformed other immunosuppressive regimens.

Conclusions: Among patients who tolerated mycophenolate mofetil, combination therapy with steroids induced remission in 67% of this cohort. Heavier proteinuria at the start of therapy and lower soluble membrane attack complex levels were associated with treatment resistance.

Keywords: Complement Membrane Attack Complex; Follow-Up Studies; Humans; Immunosuppressive Agents; Mycophenolic Acid; Recurrence; Registries; Retrospective Studies; Universities; complement; creatinine; glomerular disease; glomerulonephritis; immunosuppression; mycophenolate mofetil; proteinuria.

Figure 1.

Changes in creatinine and proteinuria in patients with C3 glomerulopathy according to response to mycophenolate mofetil therapy. At initiation of a standardized regimen of mycophenolate mofetil, responders (n=20) and nonresponders (n=10) had similar baseline kidney function. (A) Proteinuria at diagnosis is lower in responders than nonresponders. (B) Creatinine at diagnosis is similar in responders and nonresponders.

Figure 2.

Mycophenolate combined with steroids outperforms other common immunosuppressive regimens. Response to nonselective immunosuppression in C3 glomerulopathy. Mycophenolate mofetil (MMF) in combination with steroids outperforms therapy with other commonly used immunosuppressive agents with respect to complete or partial remission. Data on patients treated with other forms of immunosuppression are adapted from a Columbia University Medical Center–based observational cohort published elsewhere (33). CNI, calcineurin inhibitor.