May 14, 2015
New Hepatitis C Treatment Performs Well in Clinical Trial
May 14, 2015
May 14, 2015
A combination of three antiviral drugs cleared Hepatitis C infections from 93% of patients in a recent clinical trial.
Dr. Andrew Muir of Duke Medicine led a team of researchers from almost 50 hospitals around the world. He and other researchers administered the three drugs (daclatasvir, asunaprevir and beclabuvir) to 202 patients with Hepatitis C-related cirrhosis, or liver scarring, over a 12-week period. The three-drug cocktail even cleared the infection in 87% of the patients for whom previous antiviral treatments had not worked.
Muir was the lead author of a paper describing the work in the Journal of the American Medical Association.
According to the Centers for Disease Control and Prevention, approximately 3.2 million Americans have chronic Hepatitis C. The infection can go unnoticed as, in many cases, patients do not present any symptoms for years. The Hepatitis C virus, however, can cause cirrhosis, liver cancer, liver failure and even death in patients who carry it for long enough.
Unlike Hepatitis A and B, there is no vaccine for the Hepatitis C virus, so treatments are the only way to fight it. Many treatments rely on a type of drug called interferon. Interferons are proteins that tell cells to shut down their protein-making machinery — which viruses need to spread — and make molecules to fight viruses. The body makes them naturally but doctors can inject extra interferon to fight off many types of diseases. Interferon clears 60-80% of Hepatitis C infections.
The trouble with interferons is the side effects, especially when they are used in large doses. Often, they cause flu-like symptoms, which is difficult to deal with when treatment can go for as long as a year. Interferons can also kill off red blood cells and platelets which makes them dangerous for anemic patients or patients with low platelet counts. They can even damage the liver, which is the last thing you want to do when treating Hepatitis C.
The drug cocktail used in this clinical trial is interferon-free and is, in theory, more patient-friendly than the interferon therapies. Patients with low platelet counts responded equally well to the drug cocktail as patients with normal platelet counts, showing that this drug cocktail is potentially safer and more effective than interferon treatments.
In this trial, three out of the 202 patients suffered an adverse drug reaction, a rate of roughly 1.5%. Further trials with more patients and placebo controls will determine the full extent of these drugs’ side effects, but the initial results are promising.
The researchers also experimented with adding a fourth drug called ribavirin to the cocktail. Ribavirin is FDA approved and is commonly used in conjunction with interferons to treat Hepatitis C. Among patients who had previously received other treatments for Hepatitis C, ribavirin increased the effectiveness of the cocktail from 87 to 93%, though larger studies are needed to confirm this result.
Muir also co-authored another clinical trial using these three drugs on Hepatitis C patients who had not yet shown liver scarring. The drugs were similarly effective in that study, clearing roughly 90% of Hepatitis C infections.
Both studies show that daclatasvir, asunaprevir and beclabuvir are potentially more effective and less risky treatment options for chronic Hepatitis C than interferon. That said, these drugs must undergo large randomized controlled trials to further demonstrate their safety and efficacy before they can be approved by the FDA.
— Daniel Lane
Daniel Lane covers science, engineering, medicine and the environment in North Carolina.