Chronic hepatitis C virus infection affects approximately 1½ percent of the population of the United States, which equates to about 4 million Americans and more than 180 million individuals worldwide living with a virus that can cause significant damage to the liver.
The majority of those will develop a chronic infection that can ultimately can lead to cirrhosis of the liver and significantly increases the risk of developing liver cancer. The Centers for Disease Control estimates that approximately 12,000 Americans will die every year as a result of chronic HCV infection. In fact, chronic HCV is the leading cause of death related to liver disease and by far the most common indication for liver transplantation in the United States.
Hepatitis C infection is primarily transmitted by exposure to blood infected with the virus. Individuals at highest risk for acquiring hepatitis C include those with the following history:
» Tattoos with contaminated instruments
» Injection of street drugs with contaminated needles or sharing snorting devices
» Blood transfusions before 1992
» Work-related exposures (such as needle-stick injuries)
» Chronic hemodialysis
The majority of patients who develop chronic HCV do not have symptoms, and the primary presenting complaint is often fatigue. When infection has been active (but often, again, without symptoms) for many years, the liver begins to scar and one develops cirrhosis. The only way to ensure that cirrhosis does not develop is to completely eradicate the virus before scarring can develop.
For many years, the mainstays for HCV therapy have included pegylated interferon-alpha and ribavirin, which work as antivirals and also help regulate the immune system. The major challenges with these therapies, however, have been achieving a sustained response to therapy, meaning that the virus does not recur after antiviral therapy has been stopped. This has been a problem in patients with the subtype known as genotype 1 and in African-American patients. Unfortunately, genotype 1 infection is also the most common subtype in the United States.
The biggest breakthrough in the treatment of hepatitis C infection in many years occurred in 2011 year with the FDA’s approval of two new medications in the category known as protease inhibitors. These medications are telaprevir (Vertex Pharmaceuticals) and boceprevir (Merck Pharmaceuticals).
A protease inhibitor is added to the pegylated interferon and ribavirin regimen, and has led to a new standard of care for treatment referred to as “triple therapy.” The best results for hepatitis C viral clearance that could be obtained with interferon and ribavirin therapy alone were around 45 percent, and were even lower in African-Americans, with clearance rates at best being around 40 percent. With triple therapy, these clearance rates have significantly improved to almost 80 percent in patients who have not received any previous treatment, including more than 60 percent clearance in the African-American population.
Clearance rates also have improved significantly in patients who did not previously respond to standard therapy at all and were retreated (5 percent increased to ~30 percent), those who had some but not complete response (15 percent increased to almost 60 percent) and those who initially responded but relapsed (~20 percent to more than 80 percent). Successful eradication rates also doubled in the difficult-to-treat cirrhotic population. The availability of triple therapy has also shortened the duration of treatment from 48 to 24 weeks in the majority of patients treated with this regimen.
New medications introduced for the treatment of chronic hepatitis C infection have virtually revolutionized this field by significantly increasing response rates, reducing the duration of treatment and in general making treatment more successful and more palatable for patients. This means less risk of cirrhosis and its complications and less risk of developing liver cancer.
This also means a brighter future — and one free of the worry of having hepatitis C. If you have hepatitis C, contacting your doctor to discuss new therapies available to treat it should be the New Year’s resolution that you keep.
No comments:
Post a Comment