Results of a Phase I/II-Study on PCR-Based Pre-Emptive Therapy with Valganciclovir or Ganciclovir for Active CMV Infection Following Reduced Intensity Allogeneic Stem Cell Transplantation.

The advent of reduced intensity conditioning(RIC) protocols for allogeneic haematopoietic stem cell transplantation(HSCT) has reduced the incidence of early transplantation related morbidity largely due to the attenuation of the conditioning intensity. Nevertheless, the incidence of CMV reactivation in these patients remains high. Herein we report the results of a multi-centre randomised prospective study to assess the bioavailability(auc_0–12) of ganciclovir in the population of patients undergoing alemtuzumab-based RIC HSCT after oral administration of valganciclovir and secondly, the efficacy and safety of valganciclovir in the treatment of a CMV infection following allogeneic SCT. Recipients of allogeneic bone marrow or peripheral blood stem cell transplants with related or unrelated donors following reduced intensity conditioning, without proven graft versus host disease were eligible for this study. RIC protocols approved for the purposes of this study were FBC(fludarabine, busulphan, alemtuzumab) and FMC(fludarabine, melphalan,alemtuzumab). For inclusion into the study, patients had to have a detectable CMV DNA load in two consecutive blood specimens up to 120 days after transplant. Eligible patients were randomized to 1 of 2 treatment groups: group A received 900 mg oral valganciclovir(2 x 900 mg/d) for 14 days and group B received intravenous ganciclovir 5mg/kg/d twice daily for 14 days. All patients were monitored for 84 days(safety follow-up). pK profiles of ganciclovir were obtained after administration of the study drug in each study arm. pK assessments were scheduled at days 4 and 11. 27 patients were recruited into the study over a 24-month period from Jan 2005 to Dec 2006. The median age was 51 years(range:34–68). The median time to CMV reactivation was 43 days post-HSCT(range:20–114). 18 patients(67%) completed the allocated treatment resulting in CMV DNA load <10 copies/ml at a median of 14 days post-HSCT(range:7–28). In 9 cases, there were changes to the primary treatment regimen. In group A, treatment was modified in 5 cases; 3 due to rising CMV levels, 1 due to drug rash, 1 due to neutropenia. In group B, 4 patients had treatment modification; 3 patients due to rising CMV DNA levels, 1 had neutropenia. None of the patients in the study developed CMV invasive disease. The median value of the systemic clearance of ganciclovir was 11.8 l/h(95%CI: 8–15.6 l/h). The bioavailability of ganciclovir from valganciclovir(expressed as equivalents of ganciclovir) was 73%(95%CI, 34%–112%). The average exposure in the valganciclovir group(36.9 ± 14.9μg.h/ml) was significantly higher than in the ganciclovir cohort(27.9 ±7.5μg.h/ml). As a result, ganciclovir bioavailability in the subjects who received valganciclovir was 79%. In summary, when compared with intravenous ganciclovir, oral valganciclovir had high bioavailability with equivalent efficacy and safety in patients undergoing RIC HSCT. Use of valganciclovir can facilitate the out-patient treatment of patients with CMV reactivation post-HSCT with a potential reduction in hospitalization costs.