B cell-depleting therapy with rituximab or ofatumumab in immunoglobulin A nephropathy or vasculitis with nephritis

Approximately 30% of adult patients with immunoglobulin A (IgA) nephropathy (IgAN) or IgA vasculitis with nephritis (IgAVN) develop end-stage renal disease during long-term follow-up. In particular, patients with nephritic-nephrotic syndrome have an increased risk of rapid progression. Conventional immunosuppressive therapy with corticosteroids (CSs) may be insufficient for disease control and is associated with a number of side effects. Rituximab (RTX) has been shown to be well tolerated and effective in a range of glomerular diseases, but there is little information on its therapeutic potential in IgAN. The humanized anti-CD20 monoclonal antibody ofatumumab (OFAB) may be an alternative drug for patients intolerant or unresponsive to RTX, but so far there is no report on its use in IgAVN or IgAN.

We describe clinical outcomes after 17-22 months in four adult patients with biopsy-confirmed IgAVN or IgAN treated with RTX or OFAB as well as CS soon after diagnosis. All presented with nephritic-nephrotic syndrome and one had crescentic IgAN. Rebiopsy was performed in two cases.

RTX and OFAB were well tolerated. Albuminuria was <250 mg/day in three patients at last evaluation and two regained normal renal function. In all cases, renal function improved after therapy. In one patient with severe IgA vasculitis, rebiopsy showed disappearance of subendothelial but not mesangial immune complexes. In the case with crescentic IgAN, rebiopsy after 9 months showed no active necrotic lesions.

B cell-depleting therapy may be an alternative treatment for patients with IgAN or IgAVN and nephritic-nephrotic syndrome. A possible CS-sparing effect should be further evaluated in randomized controlled clinical trials.