Longer CMV Prophylaxis More Effective
BOSTON—Longer duration of oral valganciclovir prophylaxis against cytomegalovirus (CMV) in high-risk renal transplant patients significantly reduces the incidence of CMV infection one year post transplant, new findings suggest.
The findings emerged from the Improved Protection Against Cytomegalovirus in Transplant (IMPACT) study. This randomized, double-blind trial involved 326 CMV-seronegative renal transplant patients who received organs from CMV-seropositive donors. All patients were prescribed oral valganciclovir 900 mg daily for 100 days.
For the next 100 days, some patients continued to receive oral valganciclovir at the same dosage (the 200-day group) and others were switched to placebo (100-day group). Clinicians usually refer to the 100- and 200-day courses as three- and six-month courses.
At one year post transplant, CMV disease developed in 36.8% of patients in the 100-day valganciclovir group vs. 16.1% in the 200-day valganciclovir group, a 56% decrease, according to data presented here at the American Transplant Congress.
“That's a bigger reduction in disease than I expected at the start of the trial,” said Robert S. Gaston, MD, one of the IMPACT investigators.
The rates of acute rejection in 100- and 200-day prophylaxis groups were 17.2% and 11%, respectively, and the rates of graft loss were 1.8% and 1.9%. The differences between the groups were not significant. The study revealed no significant difference in overall valganciclovir tolerability and the incidence and grading of hematologic parameters (neutrophils, hemoglobin, and platelets).
The 100-day course of CMV prophylaxis was developed and approved at a time when rejection risk and intensity of immunosuppression were greatest during the first three months after renal transplantation, explained Dr. Gaston, Professor of Medicine and Medical Director of Kidney and Pancreas Transplantation at the University of Alabama in Birmingham (UAB).
It became apparent, however, that CMV disease often surfaced in patients a month or two after prophylaxis ended, suggesting that there might be a benefit of prophylaxis extending beyond three months, Dr. Gaston said. Moreover, transplant recipients today are exposed to extended periods of intense immunosuppression “that make a longer course of prophylaxis more desirable,” he said.
Although the IMPACT study findings are only now available, Dr. Gaston noted that many transplant centers, including UAB, have been using the six-month prophylaxis course in this patient population for the past few years.