This international Phase III study is evaluating the efficacy, safety and tolerability of prophylactic use of maribavir administered orally for up to 12 weeks for the prevention of cytomegalovirus (CMV) disease in recipients of allogeneic stem cell transplants (SCT). The study also will evaluate the pharmacokinetics of maribavir in this subject population. It is being conducted in 90 transplant centers in the US, Canada, and Europe.
This study is a randomized, double-blind, placebo-controlled, multicenter pivotal Phase III study in 681 patients who have undergone allogeneic stem cell transplantation. Following transplantation and transplant engraftment, eligible patients have been randomized to receive maribavir or matching placebo in a 2:1 randomization ratio. All patients will receive maribavir 100mg BID or placebo for a maximum duration of 12 weeks, and will then be followed for an additional 12 weeks to reach the 6-month post-transplant analyses for regulatory filing purposes. All patients will then be followed for an additional 24 weeks.
The primary efficacy endpoint will be the incidence of CMV disease within six months post-transplant, which is predicted to be approximately nine percent in the placebo (current standard of care) arm based on data from the Phase II study, data from published literature, and information from transplant center databases.
Data collection for the six-month assessments will continue through the end of November 2008. Top line Phase III clinical data is expected to be announced in the first quarter of 2009. Filing of the initial new drug application in the US, marketing authorization application in Europe, and new drug submission in Canada for maribavir in SCT patients based on the six-month assessments is expected in the third quarter of 2009.