CAMBRIDGE, Mass., June 5 /PRNewswire/ -- The investigational HIV protease inhibitor amprenavir achieves significant concentrations in the cerebrospinal fluid (CSF), suggesting that the drug crosses the blood-brain barrier and may provide potent antiviral activity in the brain, a key viral reservoir. Interim 32-week data released today showed that 8 of 9 patients achieved viral load levels in the CSF below the limits of detection for the assay used (<400 copies/mL) in two different early clinical trials involving amprenavir (formerly known as VX-478 or 141W94) in combination with Retrovir(R) (AZT) and Epivir(R) (3TC). Researchers presented the data at the 8th Annual Neuroscience of HIV conference held
this week in Chicago, Illinois.
"The development of potent antiviral regimens capable of
suppressing HIV replication in all viral reservoirs, including the CSF and other central nervous system tissues, is an important consideration for the management of HIV disease," commented Joshua Boger Ph.D., Vertex Chairman, President and CEO. "We are
encouraged by the observed antiviral effect in the CSF with this three-drug combination at 32 weeks in patients. These research findings complement a comprehensive data package being compiled now for regulatory submissions for amprenavir worldwide."
"Amprenavir was designed as a chemically compact molecule and it is this distinguishing characteristic that may allow the compound to achieve more efficient penetration of otherwise protected compartments such as the central nervous system," added Dr. Vicki
Sato, Senior Vice President of Research and Development and Chief Scientific Officer of Vertex. "Preliminary data emerging from several clinical trials suggests that amprenavir-containing drug regimens can achieve potent and durable suppression of HIV in
plasma, and are now also confirming amprenavir's penetration and activity in other viral reservoirs such as the CSF. There is more work to be done to fully characterize this activity, but we are
pleased by these early results."
Researchers analyzed CSF and plasma samples from 9 volunteers
participating in either one of two clinical trials. In the Phase II clinical trial which is ongoing, patients received escalating doses of amprenavir from 900 mg twice daily to 1200 mg twice daily in combination with Retrovir(R) and Epivir(R). In this study, 100% of patients (4 out of 4) achieved viral load suppression in the CSF to below the limit of detection (<400 copies/mL) at 32 weeks.