Background: Cytomegalovirus (CMV) is a major cause of morbidity after transplantation. Valganciclovir (VGCV) is commonly utilized for CMV prophylaxis but can cause leukopenia, with risk compounded by the use of myelosuppressive immunosuppression. By utilizing a preemptive therapeutic strategy with VGCV targeted only toward patients at risk for developing CMV disease, the rate and extent of leukopenia may be reduced.
Methods: VGCV prophylactic and preemptive strategies were compared in renal transplant recipients receiving alemtuzumab induction and prednisone-free maintenance with tacrolimus and mycophenolate mofetil (MMF). Patients were risk-stratified by CMV serologic status. All donor seropositive/recipient seronegative (D+/R-) patients, February 2002-January 2004 (n=32), received prophylaxis with VGCV 450 mg daily for 3 months. Outcomes of D+/-/R+ patients were compared. Patients in the first cohort, February 2002-October 2002 (n=61), received prophylaxis as described. In the second cohort, October 2002-January 2004 (n=110), patients were monitored by quantitative CMV-polymerase chain reaction (PCR) every 2 weeks for 3 months. If the CMV load was above laboratory threshold, VGCV 450 mg daily was initiated for 1 month or until viremia cleared.
Results: Comparing preemptive therapy versus prophylaxis in D+/-/R+ patients, there was a lower incidence of leukopenia (67% vs. 82%, P=0.039) and trend toward less granulocyte-colony stimulating factor (G-CSF) use (24% vs. 33%, P=0.196), but higher CMV disease rate (15% vs. 3%, P=0.02). One limitation was strategy compliance: 41% (7 of 17) of preemptive patients who developed CMV missed at least 1 CMV-PCR before diagnosis. One-year patient (98.2% vs. 98.4%) and death-censored graft (100% vs. 98.4%) survival was similar.
Conclusions: Antiviral toxicity may be decreased with preemptive therapy, but effectiveness for CMV prevention seems dependent upon monitoring compliance.