ViroPharma Incorporated received from the US Food and Drug Administration a fast track designation for maribavir, an oral antiviral drug candidate for the prevention of cytomegalovirus (CMV) infection in allogeneic bone marrow (stem cell) and solid organ transplant patients.

According to a company release, ViroPharma completed enrolment in a phase 2 study of maribavir in recipients of bone marrow (stem cell) transplant in November 2005, and expects to release the preliminary data from the trial by the end of the first quarter of 2006.

"There is an unmet medical need for improved treatments for the prevention of cytomegalovirus infection and disease in transplant patients due to the limitations of current therapies, which include potential bone marrow and renal toxicities," commented Colin Broom, ViroPharma's chief scientific officer.

Maribavir is a potent and selective, orally bio-available antiviral drug with a unique mechanism of action against cytomegalovirus and a favourable early clinical safety profile. It is a potent member of a new class of drugs called benzimidazole ribosides. Unlike currently available anti-CMV agents that inhibit CMV DNA polymerase, maribavir inhibits viral DNA assembly and inhibits egress of viral capsids from the nucleus of infected cells. Maribavir is active in vitro against strains of CMV that are resistant to commonly used anti-CMV drugs.

CMV is a member of the herpes virus group, which includes the viruses that cause chicken pox, mononucleosis, herpes labialis (cold sores), and herpes genitalis (genital herpes).

ViroPharma Incorporated is a biopharmaceutical company that develops and commercialises products that address serious diseases treated by physician specialists and in hospital settings.