The decision was made based on the results of the Phase 3 study of maribavir in stem cell transplant patients, and the recommendation from its independent Data Monitoring Committee who considered the rate of viremia in both arms of the study.

The Phase 3 study was a randomized, double-blind, multicenter study intended to enroll 348 subjects who have undergone liver transplantation and are at high-risk of developing CMV disease (i.e., donor CMV seropositive / recipient CMV seronegative). Following transplantation, eligible subjects were randomized to receive maribavir 100mg BID or oral ganciclovir 1,000mg TID in a 1:1 allocation ratio for up to 14 weeks. If CMV disease, defined as symptomatic CMV infection or CMV organ disease, occurred during the study drug administration period, study drug will be discontinued and the subject will be managed according to standard CMV treatment practices at the transplant center.

The primary efficacy endpoint was the incidence of CMV disease (either symptomatic CMV infection or CMV organ disease) within 6 months post transplantation, which is expected to be approximately 12 percent in the oral ganciclovir arm of the study, based on data from published literature. A number of key secondary endpoints were identified, including time to onset of CMV infection and disease; the incidence and time to onset of anti-CMV therapy; and survival without CMV infection or disease; in addition to the incidence of adverse effects that limit the use of current therapies, including suppression of bone marrow function.