Pfizer's maraviroc, the first in a new class of HIV drugs formulated to stop HIV virus from entering the immune system, has been approved by the US Food and Drug Administration (FDA).
However, only those who have had 'pharmacogenetic' test, which shows that the virus enters their CD4 cells through a particular molecule, will be given the drug.
HIV attaches itself to the CD4 receptor and to one of its two co-receptors, CCR5 and CXCR4. The drug obstructs the CCR5 co-receptor.
The FDA has approved the drug since 50 to 60 per cent of people infected by HIV, have forms of the virus that bind to CCR5.
That will be assessed by a test called Trofile. Also, Maraviroc is for people for whom HIV drugs have proved to be ineffective.
The drug will also have a warning of possible liver damage. In spite of these safety concerns, the drug has been put on fast-track by FDA due to increasing drug resistance.
"This is an important new product for many HIV-infected patients who have not responded to other treatments and have few options," New Scientist quoted Steven Galson, director of the FDA's Center for Drug Evaluation and Research, as saying.
"Maraviroc is intended for people whose other HIV drugs no longer work," he added.