ViroPharma Incorporated was a pharmaceutical company that developed and sold drugs that addressed serious diseases treated by physician specialists and in hospital settings.

Maribavir is an oral antiviral drug candidate licensed from GlaxoSmithKline in 2003 for the prevention and treatment of human cytomegalovirus disease in hematopoietic stem cell/bone marrow transplant patients.

In February 2006, ViroPharma announced that the United States Food and Drug Administration (FDA) had granted the company fast track status for maribavir.

ViroPharma conducted a Phase III clinical study to evaluate the prophylactic use for the prevention of cytomegalovirus disease in recipients of allogeneic stem cell transplant patients.

In February 2009, ViroPharma announced that the Phase III study failed to achieve its goal, showing no significant difference between maribavir and a placebo in reducing the rate of CMV disease.