The United States Food and Drug Administration (FDA) has approved adefovir dipivoxil, a nucleotide analogue that prevents virus replication, for the treatment of patients with chronic viral hepatitis B (HBV).

Citing the need for therapeutic approaches to HBV, the FDA Antiviral Advisory Committee unanimously approved the drug for oral use. If, on the whole, the FDA follows an expert evaluation and approves the drug, this will resolve the recent failure of the California branch of Gilead: in 1999, the FDA rejected the company's request to sell adefovir as a medicine to treat HIV infection. The main reason for the refusal was that at doses of 60 and 120 mg, the drug had a nephrotoxic effect.

This time, Gilead Sciences Inc. is trying to obtain approval for the daily use of the drug at a dose of 10 mg for the treatment of chronic hepatitis B in adults.

In a speech to the expert panel, FDA experts confirmed the effectiveness and safety of such a dosage. However, concerns have been expressed about the possible negative effect on the kidneys and the fact that such mutations in HIV in patients infected with HIV and viral hepatitis B are possible.

However, the advisory committee agreed that the benefits of such therapy outweigh the risk of toxic kidney effects.

According to Dr. Brian Wong, chief infectious disease specialist from Connecticut in West Haven, this drug, presented a second time for peer review in a completely different dosage regimen, now balances the benefits and risks of its use.

Studies by Gilead have shown a significant decrease in the level of the virus in hepatocytes during 48 weeks of treatment, despite the fact that the drug's ability to prevent hepatocyte death is less pronounced. The spectrum of side effects at 1 mg was similar to placebo.

However, FDA experts noted the need to monitor patients for adverse kidney effects because the drug is likely to be used for a long time.

The committee also expressed concern about the reaction to stopping the drug, as participants in clinical trials withdrawn from treatment with adefovir experienced a sharp increase in the level of liver enzymes in serum. As experts have noted, there is a likelihood of developing resistance to adefovir over time.

Gilead sought approval for adefovir in Europe and the United States in March. Since then, as part of the preliminary evaluation program, the drug has become available for the treatment of patients resistant to treatment with lamivudine (Epivir, GlaxoSmithKline).