Hepatitis

Hepatitis C is a global health problem caused by infection with the hepatitis C virus (HCV).   Around 3% of the world’s population is infected with HCV.  Most populations in Africa, the Americas, Europe and Southeast Asia have prevalence rates (measured by antibody to HCV) under 2.5%.  In the Western Pacific regions prevalence rates average 2.5-4.9%, and in the Middle East prevalence rates range from 1% to more than 12%.  Thus it is estimated that as many as 170 million persons worldwide may be infected with HCV.

In developed countries, people at risk of HCV infection include recipients of unscreened blood, blood products and organs; intravenous drug users; patients undergoing chronic haemodialysis; healthcare workers with percutaneous exposure from contaminated needles or sharps; people who participate in high risk sexual practices; and people undergoing medical or dental procedures with inadequately sterilised instruments.

Mother to infant transmission of HCV has occurred, but the risk is low unless the mother is co-infected with HIV.

Acute HCV infection is general relatively mild with only 20-30% of infected persons developing moderate ‘flu-like symptoms and jaundice.  However, 70-80% of acute HCV infections do not resolve and result in persistent viral infection that can lead to cirrhosis and hepatocellular carcinoma (“HCC”) over 5-50 years, often with fatal consequences.  Beyond the percentage of patients who self-clear, no intervention has proved able to clear chronic infection.

At present, all licensed therapies for the treatment of hepatitis C are based on interferon-α (IFN-α).  For acute viral hepatitis, treatment with IFN-α results in a sustained response rate of 50-70%.  This rate declines to about 30% in patients with minimal or mild chronic hepatitis and to about 10% among those with cirrhosis. Combination therapy using IFN- α and ribavirin has enhanced sustained response rates.  In addition to limited efficacy and the risk from side-effects, which may be substantial, the cost of therapy is high, affecting affordability in many areas of high prevalence.

At present there is no prophylactic vaccine available.  A key challenge has been the variety and changeability of the virus.  Therapeutic developments have thus far suffered from high failure rates.  At present, there are few developments either for vaccines or therapeutics close to market.  In the absence of a lot of new approaches, there is limited early-stage R&D in progress.

However, recent progress in antigen identification and with ImmunoBody technology able to target and deliver antigen, ImmBio has a programme which addresses both a prophylactic vaccine and disease management. Complete eradication of virus may be too challenging, but enhanced immune-surveillance is expected to be able to provide long term suppression of viral replication, hence avoiding progression to severe liver problems associated with chronic infection. ImmBio is collaborating with the Institute of Cell & Molecular Science, Queen Mary's School of Medicine and Dentistry, The Royal London Hospital.