Leflunomide Treatment for Polyomavirus BK-associated Nephropathy After Kidney Transplantation

Polyomavirus-associated nephropathy (PVAN) affects 1-10% of kidney-transplant (KT) patients, with graft failure/loss in approximately 90% of cases. Reducing immunosuppression is the key treatment option, but addition of leflunomide may improve BK Virus (BKV) clearance and graft survival.

Researchers at CHU Rangueil in Toulouse, France, performed a prospective open-labeled study in which 12 KT patients with biopsy-proven PVAN were treated with reduced immunosuppression and leflunomide. BKV viremia and graft function were followed.PVAN was diagnosed at 6 months (3-192) post-transplant; median serum creatinine concentration (sCC) was 189 mumol/l (92-265). After 16 months (8-30) of follow-up, the sCC was 150 mumol/l (90-378, NS). Renal function improved in six cases (50%), remained stable in two (16.6%) and deteriorated in four (33.4%), with graft loss in two (17%). Clearance of BKV viremia was observed in five (42%) cases. Side effects included anemia in six cases leading to leflunomide withdrawal in two patients, and mild thrombocytopenia. In KT patients diagnosed with PVAN, leflunomide plus reduced immunosuppression improved graft function in 66.6%, cleared BKV viremia in 42%, and resulted in side effects in 17%. This limited efficacy contrasted with other reports and fell short of expectation. The researchers concluded that active screening, earlier diagnosis and intervention remain the cornerstones of treatment.(Source: Faguer S, Hirsch HH, Kamar N, Guilbeau-Frugier C, Ribes D, Guitard J, et al. Leflunomide treatment for polyomavirus BK-associated nephropathy after kidney transplantation. Transpl Int. 2007 Jul 30; [Epub ahead of print] : August 2007)