Panacos Pharmaceuticals reports that the Food and Drug Administration has granted fast-track review status to its experimental anti-HIV drug PA-457. Currently in Phase II clinical trials, the drug is designed to treat HIV-positive people who have become resistant to available treatments as well as those who have wild-type HIV. It is the first in a new class of drugs termed maturation inhibitors. "It targets a novel point in virus replication, making it effective against viruses that are currently resistant to other treatments," Carl Wild, Panacos's chief science officer, told Reuters last July in Bangkok at the International AIDS Conference. Specifically, PA-457 blocks the processing of a viral capsid protein, preventing the full maturation of HIV copies in infected cells. These incomplete forms of the virus are unable to infect other cells in the body.
The fast-track review status will allow the FDA to approve the medication before an exhaustive review of all the clinical trial data, typically within six months of submission to the regulatory agency.
PA-457 is a once-daily oral drug, making it an attractive candidate for approval. It significantly reduced patients' blood-based HIV viral loads in early clinical trials. More complete results of those trials will be presented this month at the 12th Conference on Retroviruses and Opportunistic Infections meeting in Boston. A final Phase III trial is expected to be launched in 2006. (Reuters, with additional reporting by Advocate.com)