Timing of eculizumab therapy for C3 glomerulonephritis.

Eculizumab is an anti-C5 antibody that inhibits C5 cleavage and prevents the generation of the terminal complement complex C5b-9. Eculizumab is licensed to treat paroxysmal nocturnal haemoglobinuria or atypical haemolytic uraemic syndrome (aHUS). Clinical trials are ongoing for C3 glomerulopathy. Given the unfamiliarity of physicians with these rare diseases and the variability of clinical presentation, a delayed initiation of eculizumab therapy is common. Thus, the question arises as to what extent improvement of kidney function may be expected when patients have been dialysis dependent for weeks or months already when eculizumab is initiated. Furthermore, given the high cost and potential adverse effects of eculizumab, the question arises of when to stop therapy because of futility when patients with kidney-only manifestations remain dialysis dependent. In literature reports, eculizumab was stopped as early as after 3 weeks because the patient remained dialysis dependent. In this issue of CKJ, Inman et al. report on eculizumab-induced reversal of dialysis-dependent kidney failure from C3 glomerulonephritis, illustrating both the potential benefit of eculizumab for this complement-mediated disease and the need for lengthy therapy-dialysis independency was reached after 5 months of eculizumab. Indeed, there are reports of renal function recovery when eculizumab was initiated after 4 months on dialysis and of recovery of renal function 2.0-3.5 months after initiation of eculizumab in dialysis-dependent patients with C3 glomerulopathy or aHUS.