First, at a meeting in St. Petersburg, Florida, over 200 AIDS researchers from around the world painted a grim picture of the emerging problem of HIV drug resistance and combination treatment failure. Data suggest the drug may not show good activity in the many people who have taken the older nucleoside drugs. The recent sobering news, however, suggests that existing pharmaceutical company development programs are not finding these drugs. Over 150,000 people in the U.S. are on protease inhibitors, and recent findings suggest many of them will eventually develop drug resistance. Clearly, how drug companies find, evaluate, and develop new HIV drugs will have a major impact on whether people with HIV will have effective therapies in the years ahead.
Antivirals work by binding to a target in the virus, usually a protein or enzyme.
By attaching to the enzyme, the drug blocks or inhibits its function, and stops the virus. Because HIV is sloppy when it reproduces, however, many of its baby viruses are imperfect copies of the parent. We can think of the structure of proteins as being like strings of beads. If we change even one of the amino acids, we change the sequence, and so change the structure of the protein. If the structure of a protein changes, it makes it harder for a drug to attach to it.