Effect of Low Dose Cidofovir in Kidney Transplant Recipients with Polyomavirus Associated Nephropathy

Abstract

Background: Polyomavirus associated nephropathy (PVAN) is an important cause of graft dysfunction and graft failure in current era of immunosuppressant. First treatment is early reduction of immunosuppressant, but the rate of graft failure is still high. And there is no consensus on its management. Cidofovir, antiviral drug for cytomegalovirus, is thought to have therapeutic effect for polyomavirus, but the benefits are still controversial. Patients and methods: We treated Biopsy proven PVAN patients between 2008˜2010 in single center. All patients were treated with a reduction of their original immunosuppressive medications. 15 patients agreed to receive low-dose cidofovir (0.25 mg/kg) every 2 weeks for a total of eight doses. Result: They received mean 7.5 times (3˜14) of cidofovir with mean dose of 2.9 mg/kg (1.0˜6.5mg/kg). Mean serum creatinine level increased from 2.4mg/dl, at the start of cidofovir to 2.6 mg/dl, at the end of cidofovir. Mean BKV blood PCR reduced from 6.5 logs to 5.9 logs. There was no adverse effect of cidofovir. After 6 month of treatment, renal function was improved in 7 patients compared to at the time of initial cidofovir use. During 2.7 years of follow up there was no rejection episode but one graft failure due to chronic allograft nephropathy. Dose of cidofovir, time interval between diagnosis of PVAN and cidofovir treatment, initial BKV blood PCR level, and initial creatinine were not associated with clinical outcome. Conclusion: Adverse effect of low dose cidofovir is uncommon and low dose cidofovir therapy in PVAN patients seems to be beneficial in addition to reduction of immunosuppressant. But this small series of cidofovir use does did not prove that cidofovir in addition to immunosuppressant reduction is better than immunosuppressant reduction alone. These findings warrant a randomized controlled prospective study in order to asses the clinical value of adjuvant low-dose cidofovir.