Panacos: Bevirimat resistance does not develop rapidly

By Elaine Rigoli

Tampa, Fla., June 14 - Panacos Pharmaceuticals, Inc. presented data Wednesday demonstrating a lack of rapid emergence of resistance to bevirimat in single- and multiple-dose monotherapy studies in HIV-infected patients.

In the new report, HIV was isolated from patients prior to, and following, monotherapy with bevirimat in single-dose phase 1/ 2 and multiple-dose phase 2a clinical studies.

The amino-acid sequence of the bevirimat target, the capsid-SP1 region of the HIV-1 Gag protein, from these viruses was determined by an approach called population sequencing, which determines whether a significant proportion of virus within a patient exhibits resistance, according to a news release.

No resistance mutations previously identified in laboratory cell culture assays were seen in patient isolates from these studies, nor was there any evidence of "viral rebound," or resurgence in viral load, during the period of bevirimat treatment.

These results suggest that resistance to bevirimat does not emerge rapidly in patients, in contrast to some approved drugs where clinical resistance may be seen in the first 14 days of monotherapy.

The results are noteworthy because bevirimat has a relatively long half-life of around 2.5 to 3 days.

As a result, Panacos said patients in the phase 2a study were exposed to sub-optimal concentrations of bevirimat as monotherapy for up to three weeks following completion of the 10-day treatment period, potentially an ideal situation for resistance development.

Sequencing of the protease and reverse transcriptase genes did not reveal any new resistance mutations appearing during the study, nor did any pre-existing mutations affect the bevirimat treatment response.

Located in Watertown, Mass., Panacos develops anti-infective products through discovery and development of small molecule oral drugs.

© 2015 Prospect News.
All content on this website is protected by copyright law in the U.S. and elsewhere. For the use of the person downloading only.
Redistribution and copying are prohibited by law without written permission in advance from Prospect News.
Redistribution or copying includes e-mailing, printing multiple copies or any other form of reproduction.