By Maggie Schwarz
WASHINGTON, DC -- October 28, 2008 -- Combination cidofovir plus leflunomide either cleared or significantly reduced serum BK viral load in patients with BK virus nephropathy, according to results of a retrospective review presented here at the 48th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) and Infectious Diseases Society of America (IDSA) 46th Annual Meeting.
While BK virus, a polyomavirus, rarely causes significant disease, BK virus nephropathy occurs in up to 8% of renal-transplant patients, and is associated with renal allograft loss in 30% to 65% of cases. Treatment includes a reduction in immunosuppression (which raises the risk of renal allograft rejection), cidofovir, leflunomide, intravenous immune globulin, quinolones, and combinations of these.
This cross-sectional study examined 8 renal-transplant patients with BK nephropathy. Due to nonsignificant reduction in BK viral load and/or improvement in serum creatinine, a regimen was initiated of cidofovir (0.25 to 0.5 mg/kg weekly or bimonthly) plus leflunomide (100 mg daily for 5 days, followed by 20 to 60 mg daily to maintain serum levels 50 to 100 mcg/mL).
Four of 8 patients reached undetectable BK virus (<=200 copies/mL), allowing them to discontinue therapy. All patients had significant reductions (>=1 log) in viral load after an average of 16.8 weeks (range: 1 to 57 weeks) on the combination treatment.
There were no significant changes in calculated creatinine clearance, with an average delta change of 4.95 mL/min (range: 0.43 to 9.92 mL/min).
Diagnosis of BK nephropathy was based on serum BK viral load, increased serum creatinine, and/or kidney biopsy. After diagnosis of BK nephropathy, a renal-transplant nephrologist adjusted the immunosuppressant dose. A new BK viral load was determined 6 to 154 days after dose adjustment in 7 of the 8 patients.
Weekly serum blood urea nitrogen/creatinine and bimonthly serum BK viral load and leflunomide levels were measured throughout treatment. Cidofovir was withheld if creatinine increased >=0.2 mg/dL between measurements. There was a mean follow-up of 42.9 weeks (range: 6 to 83 weeks).
Lead investigator Mihail Paxos, a fourth-year medical student at Northeastern Ohio University College of Medicine, Rootstown, Ohio, noted that no renal allograft loss or significant reduction in renal failure was found at follow-up. No serious adverse effects were reported with this therapeutic combination.
"This combination needs to be used cautiously, but it's effective," Mr. Paxos concluded.
[Presentation title: Outcome of BK Nephropathy Treated With Cidofovir and Leflunomide in Renal Transplant Patients. Abstract V-1647]
E-Mail this DGDispatch to a colleague
