Panacos Pharmaceuticals Inc announced that it has begun a Phase 1 clinical trial of its small molecule HIV drug candidate PA-457. PA-457 has a different mechanism of action than approved HIV drugs and has potent activity against HIV strains resistant to current therapies including inhibitors of reverse transcriptase and viral protease. In the Phase 1 trial, PA-457 is being administered orally to uninfected, healthy volunteers to evaluate the compound's safety and pharmacokinetics.

Graham Allaway, Panacos' COO, commented: "The initiation of our first clinical trial is a key milestone for Panacos. More importantly, PA-457 represents a milestone for HIV drug discovery, being the first in the new class of antiretrovirals called Maturation Inhibitors that offer the promise of new treatment options for patients with HIV. Following successful completion of Phase 1, we plan to begin testing PA-457's antiviral potency in HIV-infected individuals later this year."

In recent years, there has been a dramatic increase in the prevalence of HIV strains resistant to currently approved drugs. This often leads to treatment failure, so there is a critical need for new therapies that are effective against drug-resistant HIV strains. Panacos is developing drugs with novel mechanisms of action, like PA-457, that may have broad utility for treating HIV infected patients including those harboring drug-resistant strains. PA-457 interferes with HIV maturation, a key step in viral replication that occurs as new virus particles are released from infected cells. Pre-clinical studies on PA-457 demonstrated that the compound has favorable pharmacokinetics and anti-HIV activity in animals following oral administration and suggest it should be possible to achieve therapeutic drug concentrations following oral delivery in humans.