Despite being lauded for its creativity and performance in showing the efficacy of its Viread tenofovir for AIDS, Gilead Sciences Inc. may find itself rewarded by a narrower indication than has been given to competing products as a result of changed regulatory thinking about AIDS therapies.

Members of FDA's Antiviral Drug Products' Advisory Committee and AIDS activists congratulated GILD at last week's panel review of Viread, citing the company's efforts to run trials in patients who have been treated with numerous other drugs - a territory where other companies have declined to tread - rather than in the less challenging population of treatment-naïve patients.

GILD (Foster City, Calif.) also was applauded for providing more and better virology data than previous applicants for AIDS therapies.

But the panel proved unwilling to endorse an unlimited label for Viread - instead backing use of the drug in patients who already have been treated with other antiretroviral therapies - after debating whether GILD's drug filled an unmet need in treatment-naïve patients.

An ultimate decision by FDA to confine the Viread label could signal that the agency is fundamentally revising its approach to AIDS therapies and will start treating the disease like other conditions for which there are numerous approved products.

At minimum, the trend of thinking may lead to a more stringent adherence to the requirement that new AIDS treatments clearly meet an unmet need before they can benefit from the accelerated approval mechanism.

Efficacy undisputed

The possibility that FDA will deny GILD's request for a broad indication flows from the current state of AIDS drug development, rather than disputes over the safety and efficacy of Viread. In briefing documents provided to advisory committee members prior to the meeting, FDA indicated that GILD's NDA contained "clear evidence of tenofovir's antiviral activity (over 24 weeks) when added to a stable background regimen. In two pivotal studies statistically significant reductions in HIV RNA were observed in antiretroviral-experienced patients."