ST. LOUIS — A study co-authored by a Saint Louis University researcher found telaprevir, a protease inhibitor, combined with standard hepatitis C treatment, cures a significantly higher number of difficult-to-treat patients than standard treatment alone. The findings were published in the April issue of the New England Journal of Medicine.
A member of the international research team, Adrian Di Bisceglie, M.D., chair and professor of internal medicine at Saint Louis University, studied the effects of the protease inhibitor, telaprevir, one of a new class of antiviral drugs.
“Hepatitis C remains a major public health problem. Although the number of new cases is decreasing, we have a large number of individuals with chronic hepatitis who remain at risk of progressive liver disease,” said Di Bisceglie. “Current therapies only ‘cure’ about half of those with the virus, so we desperately need new treatments for those for whom current therapy has failed.
“In this study, we found that telaprevir used in combination with peginterferon and ribavirin successfully treated and eliminated hepatitis C in up to 40 percent of patients who had failed previous treatments.”
Worldwide, experts estimate that nearly 180 million people are infected with hepatitic C. In the U.S., about 4 million people have the virus, and an estimated 10,000 to 12,000 people die from complications each year in this country.
Hepatitis C is caused by a virus, transmitted by contact with blood, and may initially be asymptomatic. For patients who develop a chronic hepatitis C infection, inflammation of the liver may develop, leading to fibrosis and cirrhosis (scarring of the liver), as well as other complications including liver cancer and death.
The prognosis varies for patients with chronic hepatitis C. With the current standard therapy, about half fully recover after an initial course of peginterferon and ribavirin anti-viral therapy that may last from six months to a year.
The remaining patients, known as non-responders, may improve with initial treatment but the virus is not eliminated. For this group, the only current option is to retreat patients with the same or similar drugs, which increase the likelihood of severe treatment side-effects. In addition, researchers have found that the success of treatment depends on the major strain, or genotype, of hepatitis C that a patient has.
In the current study, researchers examined the drug telaprevir in combination with the standard treatment of peginterferon and ribavirin. They looked specifically at the retreatment of hepatitis C for those who were initial non-responders and whose hepatitis was genotype one, known to be the most difficult strain to treat.
The trial examined the efficacy and safety of telaprevir in the treatment of 453 patients. The patients were separated into four treatment groups. Three groups were given varying combinations and durations of telaprevir along with peginterferon and ribavirin. The control group was given the standard retreatment therapy of peginterferon and ribavirin.
Researchers found that patients retreated with telaprevir fared better than patients not given telaprevir; those who received both telaprevir and peginterferon and ribavirin showed a cure rate ranging from 24 to 53 percent compared to the control groups of peginterferon and ribavirin only, which had a cure rate of 14 percent.
From their data, the authors concluded that telaprevir is indeed beneficial in combination with the current medications used in the retreatment of hepatitis C.
In addition, telaprevir treatment for 12 weeks appears to be sufficient; longer durations of treatment were not necessary. The study also showed that patients who received only telaprevir and peginterferon had a lower response, suggesting that ribavirin remains important in this combination therapy.
If telaprevir trials conclude successfully, FDA approval is anticipated as soon as 2011.
The clinical trial, PROVE3 (Protease Inhibition for Viral Evaluation 3), was funded by Vertex Pharmaceuticals.
Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first medical degree west of the Mississippi River. The school educates physicians and biomedical scientists, conducts medical research, and provides health care on a local, national and international level. Research at the school seeks new cures and treatments in five key areas: cancer, liver disease, heart/lung disease, aging and brain disease, and infectious disease.