Antiviral treatment of BK virus viremia after kidney transplantation

Purpose. The various antiviral treatment options in the management of BK virus (BKV) viremia and BKV-associated nephropathy (BKVAN) are reviewed. Summary. Review of the PubMed database from 1990 to 2016 for all English language case series, cohort studies, and randomized controlled trials detailing antiviral treatment of BKV viremia or BKVAN in kidney transplant recipients returned only 16 published reports. The majority of these reports were based on small case series or protocol-based cohort studies, with no prospective head-to-head data and only modest benefit reported for cidofovir, leflunomide, i.v. immunoglobulin (IVIG), and fluoroquinolone therapy. Given the lack of comparative data, appropriate antiviral treatment of BKV viremia should be determined based on institutional immunosuppressive protocols and posttransplantation outcomes. In appropriate patients who are not immunologically sensitized, substituting leflunomide for mycophenolate as part of immunosuppression reduction is reasonable and may result in viral clearance in up to 43% of patients at 4 weeks. In patients with persistent viremia despite immunosuppression reduction, either IVIG 2 g/kg administered over 2-5 days or cidofovir 0.5 mg/kg per week until viral clearance is achieved is generally well tolerated. Otherwise, there is insufficient evidence to recommend the use of fluoroquinolone therapy in either the treatment or prophylaxis of BKV viremia at this time. Conclusion. A review of the published literature revealed that certain populations of patients with BKV viremia or BKVAN can benefit from cidofovir, leflunomide, and IVIG therapy, but these data were derived from case series or protocol-driven cohort studies. Providers should treat patients on an individual basis to maximize clinical effectiveness while limiting adverse reactions.