Cure for AIDS still a long way away

From The NY Times:

Despite decades of effort, no magic bullet for AIDS has been invented.

The obstacles are huge. The virus mutates as fast in a day as a flu virus does in a year, but can also lie dormant indefinitely.

Since no one has ever been cured, there is no natural defense to mimic. And, since it attacks the CD4 cells that are the “fire alarms” of the immune system, vaccines that stimulate immunity may just give it more targets.

Even in wealthy countries, it can only be controlled; antiretroviral cocktails keep it from replicating. Patients are not cured, but may survive into old age.

With just four million people on treatment worldwide and donors balking at the idea of supporting 33 million or more, a miracle is needed. But none is on the horizon.

The latest failed vaccine trial, in Thailand, took six years. It may have temporarily protected a few participants, but even that required six shots spaced months apart. That is too complicated for places like rural Africa, where polio drives often fail, though they involve only a few pink drops in babies’ mouths. Dr. Anthony S. Fauci, who oversaw the Thai trial, said he saw “no chance” of a vaccine in the next few years and a “reasonable” chance of one in 20 years.

The quest for a vaginal microbicide is also stalled. Women need a product that is not messy and can be inserted secretly, because many men react furiously to any suggestion that they are infected.

Also, because many women want children, it must block a tiny virus without blocking sperm, which has been likened to stopping a million BBs streaming down a road while a fleet of Mack trucks breezes through.

Trials using sticky chemicals have proved futile. An early trial of a spermicide actually increased infections.

In July, results are due from a trial of a gel containing the antiretroviral drug tenofovir, which worked well in monkeys. It is expected to show neither a major breakthrough nor an utter failure, since, ethically, scientists would have had to stop the trial prematurely if preliminary results showed either trend.

Sharon Hillier, principal investigator for the Microbicide Trials Network, said she was still “hopeful” that such a gel, or a vaginal implant that released drugs slowly, would be ready some day.

“But,” Dr. Hillier said, “it’s going to be a long and difficult passage.”