#5 Hepatitis C Protease Inhibiting Drugs

Overview

Hepatitis C, a common liver disease that affects an estimated 3.9 million people in the United States, is transmitted through exposure to infected blood (blood was not screened for hepatitis C until 1992) and sexual contact with an infected person. The majority of people with the ailment have no bothersome symptoms, which is why health experts say millions are unaware that they even have it.

Hepatitis C is typically diagnosed when abnormal liver enzymes are identified through a routine blood test or if the infection becomes severe. Seventy percent of patients with hepatitis C develop chronic disease and 30% may develop cirrhosis of the liver within 20 years of exposure to the virus, which causes severe scarring of the liver. An additional 20% of these patients eventually develop liver cancer.

Hepatitis C virus infection is the leading cause of chronic liver disease, the reason for more than 30% of liver
transplantations, and a major contributor to as many as 12,000 deaths annually. Total medical costs for people with hepatitis C are approximately $30 billion.

To date, treatments for hepatitis C virus infection have been somewhat disappointing. The best cure rates following a 24-to 48-week course of therapy with the combination of the oral antiviral medicine ribavirin (taken three times a day) and an injectable interferon (once a week) is about 40%. The flulike side effects of these drugs are often debilitating, however, leading many patients to stop treatment. When a second round of treatment is used with this chemotherapy combination, success rates plummet to 10%. There are an estimated 300,000 Americans with hepatitis C who have failed this treatment protocol. When medical care is ineffective and the disease progresses, a liver transplant may be necessary.

Unfortunately, there are no proven medicines for patients who don’t respond to traditional hepatitis C therapy—until now, that is.

Two advanced drugs called hepatitis C protease inhibitors now awaiting approval from the Food and Drug
Administration (FDA) have the ability to fundamentally change the treatment for hepatitis C for patients who have not responded to previous therapies. Both new drugs have been very successful in curing test subjects in clinical trials, which represents a big step forward in successfully battling this debilitating disease.

The experimental drugs belong to a class of medications called protease inhibitors, which work by blocking a key enzyme that viruses need in order to copy themselves and proliferate. New data from Phase 2 trials report that when the experimental drug telaprevir, developed specifically to target hepatitis C virus, was added to standard treatments for hepatitis C, 72% of the patients achieved sustained viral response (or viral cure) after taking the medication for 24 weeks. This study confirmed that the 24-week course was just as effective as it was for patients taking the drug cocktail for 48 weeks.

Study results with a drug called boceprevir were similar with difficult-to-treat patients with hepatitis C, although cure rates were slightly lower with the three-drug combination. When combined with interferon and ribavirin, boceprevir cured the infections of about 66% of the patients who took the drugs for 48 weeks compared to 38% of those in the control group who received the standard therapy for 48 weeks.

The good news is that cure rates with these new protease inhibitors are higher than those with standard hepatitis C therapy. And so, after decades of research and expected FDA approvals, a new era of antiviral medications developed specifically to target hepatitis C virus is about to begin.

Where Are They Now

The best cure rates of hepatitis C, a common liver disease that affects an estimated 4 million Americans, come from a combination of the oral antiviral medicine ribavirin and an injectable interferon. The flulike side effects of these drugs are often debilitating leading many patients to stop treatment. There are an estimated 300,000 Americans with hepatitis C who have failed this treatment protocol.

With a new wave of all-oral Hepatitis C medication becoming available in 2013, these protease inhibiting drugs from 2011 became outdated and while they were successful treatments for these patients, in 2015 both have discontinued sales in the United States.

A company at the forefront of HVC (Hepatitis C virus) treatment has recently released a pan-genotypic regiment for the treatment of HCV in both the US and Canada as of 2016. Two of these pan-genotypic antivirals for Hepatitis C received recommendation for approval from the Committee for Medicinal Products for Human Use (CHMP) in 2017. This company is also evaluating fixed dosages of protease inhibitor regiments in studies for the treatment of chronic genotype HCV. 

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