Cytomegalovirus (CMV) is a potential complication after stem cell transplantation. There are drugs used to treat CMV, but in some patients the virus has become resistant to these drugs. The purpose of this study is to evaluate three different doses of an investigational drug called maribavir in patients with CMV infection following stem cell transplantation which is not responding to treatment with standard antiviral medications (ganciclovir, valganciclovir, or foscarnet).
Maribavir works in a different way than these standard medications, and has been shown in laboratory studies to be very effective against CMV. It is taken orally (by mouth). Patients will be randomly assigned to take one of three doses (400 mg, 800 mg, or 1200 mg twice daily).