Unistat : hepatitis c treatment
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Hepatitis C Treatment is Slowly Improving the Odds
Hepatitis C can hit the liver hard, causing critical conditions including cirrhosis and cancer. Since blood banks began screening donated blood for hepatitis C contamination in the early 1990s and other control measures have expanded, the number of new cases of the disease in the US has dropped 80%.
Normally, that would be cause for celebration - except that hepatitis C has already infected 3.9 million Americans and takes 10,000 lives each year. With hundreds of subtypes among at least six main genetic types, the virus is a tricky foe that makes vaccine development difficult and treatment an arduous and risky proposition.
"Hepatitis C is a virus that wasn't identified until 1989, but we know it has existed for decades, if not hundreds of years," said Jose Franco, MD, Medical College of Wisconsin Associate Professor of Gastroenterology and Hepatology. "Before 1989, we would have a patient with elevated liver blood tests and we would do a biopsy. It would look like viral hepatitis."
"However, the available tests at that time were for hepatitis A and B. We'd check those and results of the tests would be negative, so at that time we called it 'non-A, non-B hepatitis.' When the hepatitis C test became available, we found that the majority of those non-A, non-B cases were actually hepatitis C. It's an infection in the blood, and now by far the major risk factor for acquiring it into the bloodstream is intravenous drug use, the sharing of needles. There is also a small risk of sexual transmission."
Prior to 1992, Dr. Franco said, about 40% of hepatitis C cases were the result of blood transfusion because there was no test that could be applied to blood supplies. It is now extremely rare for hepatitis C to be acquired through blood transfusions in hospitals or emergency settings, he noted.
"Hepatitis C is the most common blood-borne infection in the United States," said Dr. Franco. "It affects 1.8% of the population. It can infect many organs, but in the majority of people the damage occurs in the liver. The word 'hepatitis' simply means 'inflammation of the liver.'"
Virus Doesn't "Clear" Naturally
One of the big problems in treating hepatitis C is that it doesn't
"go away by itself" as happens, for example, with the
common cold virus. "The majority of people who get infected are
not able to clear the virus, unlike with other types of viral
infections," said Dr. Franco. "Only about 15% can, by
themselves, get rid of the hepatitis C virus. In most patients -
about 85% - the infection becomes chronic. This means that it
persists and is documented in your bloodstream for six months or
longer."
About three out of every four patients who do not clear the hepatitis C virus within six months develop chronic hepatitis, Dr. Franco said. "With chronic hepatitis you have some scarring of the liver, some inflammation and occasional discomfort," he said. "Your liver blood tests are elevated. In about 20% to 25% of those patients, the scarring progresses to its most severe form: cirrhosis."
"In cirrhosis, the liver basically becomes replaced by scar tissue. People say 'well, the liver can regenerate itself,' which is true for a normal liver, but once the liver becomes scarred it can't regenerate. We now know that for those who progress to cirrhosis it is the leading indication for liver transplant in this country and the world. In the US, if you progress to cirrhosis, it's the number one cause of liver cancer." "In the US, the time period when most people became infected with hepatitis C was between 1970 and 1985," said Dr. Franco. "High-risk sexual behavior and IV drug use was much more prevalent. Actually, the awareness that has resulted from other diseases such as HIV and AIDS has allowed us to identify risk factors for hepatitis C as well, and patients have become more aware of the ways in which the disease spreads."
"We're hearing so much about hepatitis C today because it takes 20 to 30 years to get the cirrhosis or cancer," said Dr. Franco. "We're in the time period where the patients who were infected many years ago are now getting very sick, even though the actual number of cases has markedly decreased over the last decade."
Intravenous drug use may not be any less prevalent than it was twenty years ago, Dr. Franco said, but user awareness and needle exchange programs have made significant contributions to controlling the spread of hepatitis C. For people who already have the disease, drug therapies are evolving to reduce the harm it causes.
Success Varies by Genetic Type
"The standard of care right now is a combination of two
medications," said Dr. Franco. "A pegylated (long-acting)
form of interferon is injected once a week. The second medication is
called ribavarin and comes in pills taken twice a day. The duration
of therapy is typically six to twelve months, depending on what type
of virus you have."
"Our chances of completely eradicating the virus through treatment range anywhere from 40% to 80%, depending on what type of virus the patient has. Those figures may not seem like they're that good, but seven years ago we were only at 7% to 15%, so we've made quite a bit of progress. I suspect in five years we'll look back at the figures we have now and say that they were pretty poor."
The current drug treatment for hepatitis C is expensive, however, and the regimen can cause side effects including flu-like symptoms, depression, weight loss, sleep disruption, irritability and forgetfulness. The drugs work for about 80% of patients with Types 2 or 3 of the virus, but those types are found in only 25% of hepatitis C cases in the US. About 75% of cases in the US are Types 1a and 1b, Dr. Franco said, which are the hardest to treat and have only about a 40% rate of successful treatment.
Other medications to add to the mix are in development and the Medical College is a participant in several continuing clinical trials, according to Dr. Franco. Within five years or so, he added, the available drug "cocktail" for hepatitis C patients will likely be more effective, progressing in ways similar to the drug therapies for HIV and AIDS.
"We've identified the virus, and we know that within the virus there are different proteins responsible for different functions," said Dr. Franco. "We don't really know how the interferon and ribavarin really work, to tell the truth, but we do know that they don't knock out any of these proteins."
"Theoretically, if for example you were able to knock out one of the proteins that hepatitis C needs to attach to the liver cells, or one it needs to reproduce effectively, then the virus could not survive. So that's where we're going - to drugs that target specific proteins, whether it be the binding protein or the reproductive protein. We're not quite there yet."
Dan Ullrich
HealthLink Contributing Writer