A randomized, double-blind, placebo-controlled trial of valacyclovir prophylaxis to prevent zoster recurrence from...

Reactivation of latent VZV remains a significant cause of morbidity after SCT. Twenty-five percent or more of patients undergoing SCT will experience zoster within the first year after transplant. Short-course (<1 year) prophylaxis with acyclovir has been shown to be effective, but compliance with five times daily dosing may be problematic. We conducted a randomized, double-blind, placebo-controlled trial of valacyclovir (VACV) 1000 mg twice daily from 4 through 24 months after SCT for the prevention of VZV. Fifty-three VZV-seropositive transplant recipients (17 auto-SCT, 36 allo-SCT) were randomized at a median of 163 days after SCT. In a modified intent-to-treat analysis of 49 patients who took study drug, 0 of 22 in the VACV arm experienced zoster reactivation, compared with 6 of 26 (23%) in the placebo arm (P=0.025). Thirty-two subjects completed therapy through the second year post transplant or first episode of zoster. Adverse events resulting in discontinuation were more frequent in the placebo group (5 of 26 vs 3 of 27 for placebo and study drug, respectively). VACV at a dose of 1000 mg twice daily through 24 months after transplant is well tolerated and effective in suppressing shingles after SCT.