Gilead Sciences Inc.'s announcement late Friday that it will discontinue U.S. development of adefovir dipivoxil to treat HIV comes as no surprise. But the company maintains that the problems that led the FDA's Antiviral Drugs Advisory Committee to vote against approval last month don't apply to related compounds in the company's pipeline.

In November, the FDA panel said that GILD (Foster City, Calif.) had failed to demonstrate the safety and efficacy of the nucleotide as a treatment for HIV (see BioCentury Extra, Nov. 2). Last week, GILD disclosed that FDA has concluded that additional trials would be required for approval, leading to the abandonment of adefovir for HIV in favor of its second-generation tenofovir dipivoxil.