Chronic infection with the hepatitis B virus (HBV) is responsible for an enormous burden of disease throughout the world, including up to half of all cases of cirrhosis, end-stage liver disease, and hepatocellular carcinoma, a cancer of the liver.
Although relatively rare in the United States, Hepatocellular carcinoma is one of the top causes of cancer deaths world wide.
It is prevalent in parts of Asia and Africa.
It is estimated that 1.5 million Americans carry the hepatitis B virus, which is spread by contaminated needles or sexual contact.
The disease is frequently fatal.
The development of a safe and effective vaccine in the early 1980s, has meant that hepatitis B has become a preventable disease.
Two new studies on long-term liver disease carried out a comparison of two drugs used to treat hepatitis B, Entecavir a new drug produced by Bristol-Myers Squibb, and Epivir produced by GlaxoSmithKline.
Researchers at the National Cheng Kung University Medical College in Taiwan, found that in patients with chronic hepatitis known as HBeAg-positive, Entecavir was more effective than Epivir.
The team led by Ting-Tsung Chang found that 72 percent of the 314 patients treated with Entecavir showed improvement after 48 weeks of treatment.
Among the patients who were treated with Epivir, known generically as lamivudine, only 62 percent of the 314 patients improved in the same time.
Apparently Hepatitis B virus particles dropped to undetectable levels in 67 percent of the people in the Entecavir group, compared with 36 percent of the Epivir recipients.
A second study of 583 HBeAg-negative patients, conducted by many of the same researchers, showed similar results.
Jay H. Hoofnagle, M.D. from the National Institute of Diabetes and Digestive and Kidney Diseases, says Entecavir appears to be "an outstanding agent for treating chronic hepatitis B," because of its effectiveness and the low rate at which the hepatitis B virus becomes resistant to the drug.
Hoofnagle does however warn that treatment may still be complicated as it is still unclear who should be treated, with which agent (or combination of agents), and for how long; and what is the best way to monitor patients.
Hoofnagle also points out that the virus can develop a resistance to one of the drugs; after four years of taking lamivudine, it seems 70 to 80 percent of patients become resistant to it.
Hoofnagle says the low rate of antiviral resistance to Entecavir is possibly it's most promising feature.
It appears that if people stop taking anti-hepatitis drugs, the disease returns with a vengeance, which is often fatal.
The two drugs are among five approved in the United States to treat the often deadly illness.
A vaccine that prevents hepatitis B is also available, and is routinely given to newborns in Taiwan and China, where the illness is common.
In the United States, a month's supply of 0.5 milligram tablets of Entecavir, sold under the brand name Baraclude, costs about $650, which is about four times the cost of lamivudine.
The research and the comments by Hoofnagle are published in the New England Journal of Medicine.