Recent progress in the fight against Aids shows that throwing money at problems can workby John Maddox / August 20, 1996 / Leave a comment
Just over a year ago, I had a long talk with an immunologist in the US about the prospects of more effective ways of dealing with HIV infection. She had just come back from a meeting to talk about the likelihood of an effective vaccine being developed. She said that on the evening of the second day, she had gone back to her room and wept, so bleak was the outlook.
Now the mood is changing. For the first time in a dozen years, there is talk of the possibility of a cure for Aids. But there is great caution this time round. People are all too used to disappointment.
New hope stems not from a vaccine, but from the development of new drugs called protease inhibitors, the first of which was licensed by the US food and drug administration last December. Now there are half a dozen alternatives on or near the market. Since these materials were first in clinical trials, physicians have been reporting almost dramatic improvements in the condition of Aids patients on their books: the loss of debilitating symptoms, weight gain and, even more significantly, the return of the “feel-good factor.” There is some evidence that the HIV virus can no longer be detected in the blood of some of those previously infected.
Where have these wonder drugs come from? They spring directly from what has been learned in the past decade of the molecular structure of HIV, which shares with all other viruses the property that it can replicate itself only by subverting the machinery of an infected cell to its own ends.
HIV has evolved an especially economical way of doing this. The virus has evolved a long protein molecule, normally wrapped round its own genetic material-a package of subverting enzymes that functions as a kind of molecular Trojan horse. Once inside a white blood cell, the package is cut into its component pieces by the protease it also carries. As much as five years ago, Dr Samuel Broder, then the director of the National Cancer Institute in the US, drew attention to the vulnerability of HIV to drugs that inhibit the protease enzyme.
By January last year, the first protease inhibitors were used in studies that will eventually be recognised as the turning point in Aids research. Previously, it had been thought that the first result of HIV infection was that the…