Abatacept experience in steroid and rituximab-resistant focal segmental glomerulosclerosis.

Primary focal segmental glomerular sclerosis (FSGS), one of the major causes of nephrotic syndrome, eventually results in end-stage renal disease. Currently, FSGS is treated with immunosuppressive therapies, which include calcinuerin inhibitors (cyclosporine), glucocorticoids, B-cell depleting agents (rituximab) and, recently, a T-cell co-stimulatory inhibitor (abatacept). Until recently, there had been no cases reporting resistance to all current therapies. We report a case of a 62-year-old Caucasian man with biopsy-proven FSGS, who responded well to oral prednisolone therapy. However, 2 years later, he had a relapse and failed to respond to prednisolone. Subsequent treatments then included cyclosporine, rituximab and cyclophosphamide, which were not successful. The patient was then administered abatacept, a novel T-cell co-stimulatory inhibitor-though he did not experience any side effects, there was no change in proteinuria nor in creatinine.