New cut-offs will provide more realistic picture of resistance
GLASGOW, SCOTLAND, October 23, 2000 - Data presented today at the 5th International Congress on Drug Therapy in HIV Infection identified and discussed new drug-specific, biological cut-off values developed by Virco for its HIV drug resistance tests. These will tell clinicians instantly whether their patient's virus is within the normal susceptible range found in untreated patients or whether biologically relevant resistance has developed. The new cut-offs are unique to each drug, varying from 2.5 for some of the protease inhibitors up to 6-10 for the non-nucleosides, and will provide clinicians with an indicator of resistance that more realistically mirrors the situation in the clinic.
"These are the first biologically relevant cut-offs to be used in HIV resistance monitoring and represent an important advance in terms of the practical utility of drug resistance information," said Julio Montaner, MD, Professor of Medicine and Chair in AIDS, University of British Columbia, Vancouver, Canada. "Using these new cut-offs will take some of the guess work out of the interpretation of resistance results, which is good news, both for clinicians and their patients."
The new cut-offs are based on the natural biological variation of tens of thousands of virus samples from patients in the USA and Europe and will be integrated into Virco's HIV drug resistance testing services (Antivirogram and VirtualPhenotype) worldwide over the next few weeks.
Until now resistance tests have used somewhat arbitrary cut-offs (the threshold above which HIV is categorised as being resistant to a drug) that were, for example, based on the reproducibility of the tests themselves. Resistance was measured directly in terms of how much drug was required to inhibit the replication of the virus by 50% (the IC50), and then, compared to the IC50 for a laboratory standard reference virus. By re
Contact: Peter Vigliarolo
Cooney Waters Group, Inc.