Regimen revolution
HEPATITIS C is a silent killer. Because the incubation period for the virus is 20 years or more, many people are unaware they’re infected until irreparable liver damage has occurred.
Even with early diagnosis, treatment options are limited, and up to half of sufferers don’t respond to standard drug therapy. Side effects -- flu-like symptoms, depression, fatigue -- can be so severe that some patients stop treatment.
For the record:
12:00 a.m. Oct. 31, 2005 For The Record
Los Angeles Times Tuesday October 25, 2005 Home Edition Main News Part A Page 2 National Desk 1 inches; 48 words Type of Material: Correction
Hepatitis C -- An article in Monday’s Health section about experimental hepatitis C treatments said that, in a trial, the drug Valopicitabine reduced virus levels by up to 90% after 12 weeks of treatment. In fact, it took two weeks to reduce viral levels by more than 90%.
For The Record
Los Angeles Times Monday October 31, 2005 Home Edition Health Part F Page 8 Features Desk 1 inches; 49 words Type of Material: Correction
Hepatitis C -- An article in last week’s Health section about experimental hepatitis C treatments said that, in a trial, the drug Valopicitabine reduced virus levels by up to 90% after 12 weeks of treatment. In fact, it took two weeks to reduce viral levels by more than 90%.
About 10,000 Americans die each year from chronic hepatitis C infection, but death rates are expected to triple over the next decade and far surpass those of AIDS.
Experimental medications in the research pipeline may avert this looming public health crisis. More than two dozen hepatitis C drugs are in development, and at least three drugs potentially could stop the lethal virus in its tracks by preventing it from reproducing.
“These drugs are more potent and have much less side effects, so the hope is that more people will come forward to be treated,” says Dr. Eugene R. Schiff, director of the Center for Liver Diseases at the University of Miami in Florida.
The current treatment combines a synthetic version of pegylated interferon, a protein that bolsters the immune system, and ribavirin, which slows viral replication. However, fewer than half of people infected with the most common strain of hepatitis C respond to injections of that regimen.
The new antiviral therapies seem to effectively combat this strain, genotype 1, without those side effects. They also come as pills instead of shots.
Valopicitabine, made by Idenix Pharmaceuticals, is furthest along in its development. It works by blocking the action of RNA polymerase, an enzyme crucial to reproduction of the hepatitis C virus. A 2004 test of 79 patients revealed that the once-a-day pill reduced viral levels by up to 90% after 12 weeks of treatment -- even though previous drugs hadn’t worked for 87% of those patients.
Preliminary results from a recent Idenix test of Valopicitabine combined with pegylated interferon also show significant reduction of viral replication. The interim results of this trial, which used 190 patients unresponsive to conventional therapies, will be released next month.
Like the drug cocktails that transformed AIDS treatment, Valopicitabine will probably be part of a combination regimen, said Dr. Nathaniel Brown, chief medical officer at Cambridge, Mass.-based Idenix. “But we’re in a race against time because the number of people with advanced disease is steadily increasing.”
Two other experimental drugs have just completed early stage tests: SCH-503034, made by Schering-Plough in Kenilworth, N.J., and VX-950, made by Vertex in Cambridge.
Both disable a different enzyme, protease, thus preventing the virus from making copies of itself. Schering tested its drug -- alone and in combination with pegylated interferon -- on genotype 1 patients who didn’t respond to standard treatments. Results of those trials will be released in November, and Janice K. Albrecht, a liver expert with Schering-Plough, says the reduction in viral levels was “significant.”
A 2005 study of VX-950 using 34 volunteers was even more promising. After two weeks of treatment, the oral medication proved 250 times as potent as standard therapy in reducing viral levels.
Additional studies for both drugs are being planned.
“This data is profoundly encouraging,” says Dr. John Alam, senior vice president for drug evaluation and approval at Vertex. “Within the next three to five years, a new generation of hepatitis C treatments could be available that can clear the virus in most patients.”
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Hepatitis C at a glance
Hepatitis C is spread through contact with infected blood. Before the virus was identified in 1989, people got it by receiving blood or organs from infected donors.
The blood supply is now screened, but IV drug users are still at risk.
About 4 million Americans are hepatitis C carriers, and 2.7 million of them have an active infection. Because there is no effective treatment for the majority of patients, hepatitis C infection accounts for 40% of terminal cirrhosis, 60% of liver cancers, and is the leading cause of liver transplants in the United States.
