Health Conditions

What is on the horizon?

Several new treatment options are under investigation for hepatitis C. One of the most exciting of these is the Specifically Targeted Antiviral Therapy (STAT-C), which resembles the model of the antiretroviral HIV therapy affecting different steps in the replication process of HCV.

Protease Inhibitors

There are three different protease inhibitor agents that are currently being studied in hope that they will help reduce the amount of HCV present in the blood. So far all three drugs are showing promise in that they have reduced the amount of HCV in the blood when combined with pegylated interferon alfa-2a. Further studies need to be done to determine the safety of these drugs, and one major downfall to protease inhibitors is that they must be taken at least three times a day to be effective.

Inosine Monophosphate Dehydrogenase (IMPDH) Inhibitor

A new class of drugs called inosine monophosphate dehydrogenase (IMPDH) inhibitors is believed to work by interfering with an enzyme used by HCV to multiply. One member of this class, currently known as merimepodib or VX-497, is being investigated for the treatment of hepatitis C in individuals that do not respond to combination therapy with interferon and ribavirin. Although they also need to be used with interferon, IMPDH inhibitors appear to work in ways that are similar to the ways that ribavirin helps to normalize liver tests.

Hammerhead Ribozymes

Ribozymes are proteins capable of breaking down the genetic material of viruses. A new treatment strategy is studying hammerhead (named because their chemical structure is shaped like a hammer's head) ribozymes to prevent HCV replication. Therefore, the chance that the body can eliminate HCV increases. Preliminary results from treatment with hammerhead ribozymes are promising, with one study showing that some of them may inhibit virus duplication by as much as 95%. Combining a ribozyme with interferon possibly could increase inhibition of the virus to 99% or more.

Alkovirs

Alkovirs are another new class of drug currently being tested for the treatment of both HCV and hepatitis B virus (HBV). Because alkovirs, which are taken orally, may activate the body's own immune system, they may act like interferons. As a result of treatment with alkovirs, the body may be able to eliminate HCV before liver damage becomes severe.

Albuferon

Albuferon is a longer-acting form of interferon alfa and only has to be administered every 2 weeks versus every week for pegylated interferon alfa. This agent is currently being studied in combination with ribavirin testing the safety and how well the drug actually works in reducing HCV levels. The studies are also testing the percentage of those individuals who relapse (meaning, the treatment doesn't work for them) and so far, the studies are showing that albuferon has a decreased rate compared to pegylated interferon.

Polymerase Inhibitors

Polymerase Inhibitors terminate the virus's ability to replicate which helps to decrease the amount of HCV in the blood. A drug in this category is now in clinical trials and shows a higher response rate than current HCV therapy. The drug is codenamed R1626, and is being highly awaited for since it shows high effectiveness and a high barrier to resistance, which does not allow HCV to become resistant to it easily.

Other Experimental Therapies

Several potentially useful therapies are still in very early stages of experimental stages. They include:

• Antisense Oligonucleotides (a new class of drugs thought to prevent the replication of HCV in ways different from the way that ribozymes are believed to work)
• Hepatitis C Vaccine (researchers are trying to not only find a preventative vaccine, but also one that will treat the HCV infection)
• Intracellular Antibodies (use of an individual's own defensive proteins to fight HCV)
• T-cell Immunotherapy (boosting the activity of virus-specific immune cells)
• Polymerase Inhibitors (a drug that terminate the virus's replication helping to decrease the amount of HCV in the blood)