Entecavir approved for chronic hepatitis B.(News)

GAITHERSBURG, MD. -- Entecavir, an oral antiviral drug that has several advantages over currently available treatments for chronic hepatitis B, was approved recently by the Food and Drug Administration.

The approval came after the unanimous recommendation of all 18 members of FDA's Antiviral Drugs Advisory Committee who agreed that the risk-benefit appraisal of entecavir supported its approval for treating chronic hepatitis B virus (HBV) infections in adults. Despite concerns about a theoretical risk of malignancies in humans, the panel voted in favor of approval, citing the very real risk of hepatocellular carcinoma associated with chronic HBV, the safety and effectiveness data in 48-week trials of more than 1,000 patients who were either treatment naive or refractory to lamivudine, and the lack of significant evidence of resistance to date.

There is "no question" entecavir is very effective at reducing viral load, said Leonard Seeff, M.D., senior scientist for hepatitis research at the National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Md., who is a member of the panel.

"We need other treatments, and this drug has advantages that others don't--namely, at least at this point, a lower rate of mutant strains developing and no nephrotoxicity," he remarked.

Both he and the other panel members agreed that entecavir should be considered a first-line therapy for treatment-naive patients, emphasizing that the development of resistance needs to be followed closely.

The drug's manufacturer, Bristol-Myers Squibb (BMS), has agreed to conduct a large postmarketing study to determine whether the increased risk of lung tumors and other malignancies seen in rodents would occur in humans, and whether resistant strains would develop with a longer duration of treatment. The multinational trial would aim to enroll 12,500 patients worldwide, randomize them to entecavir or another HBV drug treatment, and follow them for malignancies and progression of liver disease for 5-8 years, according to BMS.

But the panel was concerned that the company could have problems enrolling enough patients in the trial, because entecavir was shown to be more effective than lamivudine in trials.