Drugs to boost the immune response

The success of interferon based treatment has shown that HCV can be reduced to undetectable levels by boosting the immune response to fight the virus. Drug companies have been looking to see if other ways of stimulating our immune system might be effective against the virus. The most advanced research involves the receptors we use to sense the presence of invading microorganisms such as bacteria, viruses and parasites. These are called toll-like receptors (TLRs).

So far, ten different TLRs have been identified in humans. Four of these have been shown to specialize in the recognition of the nucleic acids of viruses.

When stimulated, TLRs pass on signals essential to the immune response. TLRs are in part responsible for triggering the inflammatory response to the presence of a virus by activating proteins called cytokines. Cytokines act as chemical messengers within the immune system, passing on signals to enable other reactions to take place. They in turn stimulate other parts of the immune system vital to fighting HCV infection.

8th July 2008 - Anadys Pharmaceuticals announced that it is resuming clinical investigation of the Toll-Like Receptor-7 (TLR7) mechanism for the treatment of chronic hepatitis C. Based on preclinical pharmacology testing and the results of completed 13-week GLP animal toxicology studies, Anadys has received clearance to initiate a clinical trial of ANA773, the Company's oral TLR7 agonist prodrug, under a clinical trial application (CTA) in the Netherlands. Following initial dosing in healthy volunteers, this trial will explore every-other-day dosing over 28 days in HCV patients