FDA fast tracks first-in-class HIV drug
and Drug Administration (FDA) granted Fast Track designation to the
first in a new class of HIV drugs called Maturation Inhibitors.
Fast Track is a process designed to expedite development and approval of new drugs that may have the potential to improve treatment for serious or life-threatening diseases. Developers of Fast Tracked products have greater access to FDA resources as well as eligibility for rolling NDA submissions. In addition, Fast Track designation may enable priority FDA review and accelerated approval.
The once-daily oral drug candidate for the treatment of HIV infection, PA-457, produced by Panacos Pharmaceuticals. Panacos has completed single dose (Phase Ia) and multiple dose (Phase Ib) studies of PA-457 in uninfected volunteers, demonstrating the drug is well tolerated with pharmacokinetics supporting once-daily oral dosing.
Panacos recently announced positive results from a proof-of-concept Phase I/II clinical trial of PA-457 in HIV-infected patients, where a single oral dose of the drug gave a significant reduction in plasma viral load from baseline.
Dr David Martin, senior vice president of drug development at Panacos, said: "The granting of Fast Track status will enable us to get rapid input and feedback from FDA on our clinical program, and we believe that it will help us move PA-457 quickly into late stage clinical development."
PA-457 is a small molecule, orally bioavailable HIV drug candidate. It inhibits HIV replication by disrupting virus maturation, the last step in the virus life cycle. Specifically, PA-457 blocks a key step in the processing of a viral core protein called capsid. Preclinical studies have shown that PA-457 retains full activity against drug-resistant virus and is effective in an animal model of HIV infection.
"We believe that PA-457 has great potential as a new approach to treat HIV/AIDS and are pleased the FDA has chosen to grant Fast Track status, which will allow us to expedite development of this drug," commented Dr Graham Allaway, Panacos' chief operating officer.
"There is a major need for treatments effective against drug-resistant strains of HIV, which appear in most patients receiving therapy and are the leading cause of treatment failure. PA-457 has a different mechanism of action than approved HIV drugs and as a result it potently inhibits HIV strains resistant to currently available treatments as well as wild-type virus."
PA-457 is an example of a compound that has a novel mechanism of action and therefore is active against HIV strains that are resistant to current reverse transcriptase and protease inhibitors. As such, this drug candidate offers a completely new approach for treating HIV/AIDS.
Although the introduction of antiviral drugs has improved life expectancy around 270,000 US patients resistant to at least one class of HIV drug. Around 50,000 have developed resistance to all three currently available drug classes.
In addition, up to 20 per cent of new infections now involve the transmission of resistant virus, meaning new classes of antiviral drugs (especially against novel targets) will provide the only hope of treatment for an increasing number of patients.
