Drug-Resistant HIV Found
The discovery of a previously unknown, drug-resistant strain of HIV, the virus that causes AIDS, could lead to better treatments for patients with that strain, researchers said Tuesday.
The new strain of HIV was isolated by Quest Diagnostics Inc., a New Jersey-based research company, and the Center for AIDS Research at the Stanford University School of Medicine.
The strain has reduced susceptibility to reverse transcriptase inhibitors, a class of antiviral drugs, Quest said.
Reverse transcriptase is a part of the HIV virus that allows it to make copies of itself and spread through the body.
Transcriptase inhibitors, such as Retrovir and Videx, stop the virus from reproducing. But they don't work for everybody, partly because some strain of the ever-changing HIV virus are impervious to these drugs.
The Quest and Stanford researchers found that in the new strain, a slight change in one part of the genetic code for the HIV virus makes four to eight popular inhibitor drugs less useful against the strain.
A Quest scientist said that cataloguing all the drug-resistant strains of HIV is key to developing new therapies to help patients infected with those strains. Finding the new strain is a step in that process.
"This is good because it allows us to detect one more group of patients that were not identified earlier with this type of mutation," said Quest vice president Dr. Jorge Leon. "It will allow us to cover more patients with drug resistance."
HIV's extraordinary mechanism for mutating is what makes the disease hard for the human immune system to fight, and has prevented the development of a cure for the disease.
"The virus has an intrinsic capacity to respond to external agents and mutate and that's within the virus," Leon said. "Not every virus has the capacity to mutate that this virus has."
Scientists aren't sure what it is about the HIV virus that makes it so elusive. But Leon said the main causes of mutation are drugs and the human body.
The virus responds to drugs intended to kill it and human antibodies by mutating to extend its life.
The findings, which were published in the November Journal of Virology, are being used by Quest to report laboratory results for its HIV-1 genotyping test, the company said.