Ribapharm Inc has submitted an Investigational New Drug (IND) application to the U.S. Food and Drug Administration (FDA) to initiate Phase I clinical studies for Hepavir B in patients with chronic hepatitis B.

"Ribapharm licensed the rights to develop and commercialize Hepavir B from Metabasis Therapeutics Inc. in October 2001," said Johnson Y.N. Lau, President and CEO of Ribapharm. "This filing, one year after securing the rights to Hepavir B, underscores the commitment of the development team and the strategic value of the partnership between Ribapharm and Metabasis."

Metabasis discovered Hepavir B by applying its HepDirect prodrug technology to a proven effective antiviral drug, PMEA. The HepDirect technology is a proprietary platform technology discovered and developed by Metabasis. In animal studies, Hepavir B is predominately converted into the active moiety in the liver.

"Although Hepavir B is still in Preclinical Phase of development, it represents an interesting prospect as the efficacy of the active compound, PMEA, has been demonstrated to be active against both wild type and drug resistant hepatitis B," said Robert Gish, Director of Hepatology and Liver Transplantation, California Pacific Medical Center, San Francisco.

A Phase I clinical study on the safety of rising single doses of Hepavir B in healthy volunteers was conducted in Europe in August 2002. The study showed that the incidence of treatment-emergent adverse events associated with single oral doses of Hepavir B were 3 at 10 mg (6 subjects), 6 at 30 mg (12 subjects) and 0 at 60 mg (6 subjects) versus 5 with placebo (4 subjects), indicating that single oral doses of Hepavir B up to 60 mg is comparable to placebo in healthy adult volunteers.

Hepatitis B is a viral infection of the liver. The World Health Organization (WHO) estimates that more than 350 million people worldwide have chronic infections. In the United States, the Centers for Disease Control and Prevention (CDC) estimate nearly 78,000 people each year are newly infected with hepatitis B.

Chronic infection by the hepatitis B virus can lead to cirrhosis and liver failure, as well as liver cancer in the more advanced stages of the disease. The CDC estimates that death will occur in 15 to 25 percent of people chronically infected with hepatitis B. Hepatitis B is highly infectious and occurs when blood or body fluids from an infected person enters the body of a person who is not immune or vaccinated. The virus is often spread through sexual contact with an infected person. Contaminated needles used in intravenous drug injections and blood transfusions from infected sources also spread the virus to otherwise healthy individuals. Hepatitis B infection can also be spread from mother to baby at birth.