Oral valganciclovir leads to higher exposure to ganciclovir than intravenous ganciclovir in patients following allogeneic stem cell transplantation

Abstract

Cytomegalovirus (CMV) infection is a major complication after allogeneic stem cell transplantation (SCT). Valganciclovir (V-GCV) is an oral prodrug hydrolyzed to the anti-CMV drug ganciclovir (GCV). A randomized, multicenter, crossover, open-label clinical trial compared exposure to GCV after V-GCV and intravenous GCV (IV-GCV) as preemptive therapy for CMV disease in SCT. The primary objective was to compare exposure to GCV in patients with CMV infection stratified for intestinal graft-versus-host disease (I-GVHD). Secondary objectives were the assessment of safety and efficacy. Patients without I-GVHD had a higher exposure to GCV after V-GCV when compared with IV-GCV (area under the concentration-time curve from drug administration to last observed concentration after 12 hours [AUC_0-12] 53.8 ± 17.97 μg/mL · h [mean ± SD] vs 39.5 ± 13.91; P < .001; ratio of V-GCV/IV-GCV was 1.4; 90% confidence interval [CI], 1.2-1.5). This was also true in patients with I-GVHD grades I-II (AUC_0-12 52.9 ± 21.75 vs 33.1 ± 12.97 μg/mL · h; P = .018; ratio 1.6; 90% CI, 1.3-2.0). Absolute bioavailability of GCV after V-GCV was approximately 75% in individuals with or without I-GVHD grades I-II. No severe GCV-related toxicity was observed and efficacy and safety was comparable (84-day follow-up). This supports the use of V-GCV in SCT, even in patients with I-GVHD grades I-II. Due to higher exposure after V-GCV compared with IV-GCV, patients should be monitored carefully for safety reasons.