HCV
HEPATITIS C - ANTIVIRAL
A NEW APPROACH TO AN ELUSIVE DISEASE
Hepatitis C Virus (HCV) is one of five currently identified viruses – Hepatitis A, B, C, D, and E – all of which can attack and damage the liver. The disease affects 180 million people around the globe, with 100 million people chronically affected. Widely viewed as one of the most serious of the five types, the Hepatitis C virus (HCV) is spread primarily through contact with infected blood.
HCV exists in many different forms, called genotypes, confounding researchers in their quest to develop a vaccine effective for all variations. Also, HCV mutates frequently within infected patients, so even if an effective vaccine is developed, it could be rendered useless by a new strain of mutant virus.
Therapeutic Potential
With only half of all treated HCV patients benefiting from current therapy, medical unmet needs are high. The current standard of care is a combination of interferon and the antiviral drug ribavirin. Interferon is a genetically engineered biological drug. Hepatitis C patients must inject themselves with interferon, usually three times a week.. The combination of ribavirin and interferon therapy appears to suppress blood levels of HCV more effectively than a first or repeat course of interferon alone (monotherapy). Ribavirin, when used alone, does not work.
Interferon monotherapy is generally reserved to treat patients in whom ribavirin is contraindicated. In about 25 percent of patients, the drug has a pronounced effect, reducing HCV to very low levels in the blood. However, if the drug is ineffective after three months, doctors probably will discontinue it.
Successful treatment resulting in reduction of viral loads and improved clinical symptoms can unfortunately be accompanied by side effects. Patients can suffer from extreme fatigue, flu-like side effects such as fever, chills and body aches and they can also suffer bouts of depression, rendering them unable to work or attend school. Ribavirin can cause anaemia, and interferon is associated with both psychosis and suicidal behaviour, though the latter occurs in just one to two percent of patients. Ribavirin also presents significant potential risks for pregnant women, including possible foetal death or malformations.
Currently, chronic Hepatitis C patients who do not respond to therapy have few options. In many, cirrhosis or other damage will eventually cause the liver to stop functioning. In these cases, a liver transplant is the only recourse. However, even new livers often become infected with the virus.
Project Status
Avexa has announced a partnership with TargetDrug on the HCV project. The project is currently in the early discovery stage. Avexa is putting screens together and evaluating a number of targets that have received limited attention as drug-discovery targets, to determine which of those will deliver drugs most effectively.
Scientific Rationale
Avexa’s chosen targets for interrupting HCV replication have not been disclosed as yet. It has been determined, however, that the chosen targets are essential for replication and maturation of the Hepatitis C Virus. Thus, the targets should provide selectivity for the medicine’s mechanism of action.
