ViroPharma Incorporated today announced that the U.S. Food and Drug Administration (FDA) has granted orphan drug designation for maribavir for prevention of cytomegalovirus (CMV) viremia and disease in the populations at-risk.
The Orphan Drug Act was designed to provide incentives to companies to develop drugs that treat conditions affecting 200,000 or fewer patients annually in the U.S. and that provide a significant therapeutic advantage over existing treatments or fill an unmet medical need. Orphan drug designation entitles ViroPharma to seven years of market exclusivity in the United States upon FDA approval of maribavir, provided that the company continues to meet certain conditions established by the FDA. Other potential advantages include protocol assistance, the potential for priority review, tax credits, and other financial incentives.
"We are particularly pleased to receive orphan designation for the product from the FDA," commented Colin Broom, M.D., ViroPharma's chief scientific officer. "We have made excellent progress with maribavir over the last 12 months. We demonstrated in a Phase 2 clinical trial that the drug appears to be well tolerated with impressive anti-CMV activity in stem cell transplant patients, which has allowed us to initiate our international Phase 3 development program. The receipt of this designation marks one more important milestone in the development of the compound. Maribavir is an important Phase 3 drug candidate for a significant unmet medical need, and may one day provide an effective and well tolerated therapeutic alternative for patients at risk of CMV disease."
Maribavir is a potent and selective, orally bioavailable antiviral drug with a unique mechanism of action against cytomegalovirus and a favorable 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 egress of viral capsids from the nucleus of infected cells. Maribavir is also active in vitro against strains of CMV that are resistant to commonly used anti-CMV drugs.