In one of the most promising developments in more than 20 years, scientists claim that drugs used to control HIV/AIDS in patients may also be effective in preventing the disease in the first place.
The drugs in question are tenofovir (Viread) and emtricitabine, or FTC (Emtriva), sold in combination as Truvada by Gilead Sciences Inc. Gilead is the California company best known for inventing Tamiflu.
Previous research has been aimed at finding a vaccine against HIV/AIDS, with the intention of conditioning the immune system against the disease. But these drugs work differently. They simply keep the virus from reproducing, and have already been used successfuly by health care workers to prevent them from being infected by the virus carried by patients.
This approach to fighting HIV/AIDS has been tempting researchers for many years, but has only recently become feasible as preventative drugs have been developed that are safe for non-infected persons to take. Previous drugs had unreasonable effects for uninfected persons.
That situation changed when Tenofovir came on the market in 2001. Tenofovir is powerful and safe, and it only has to be taken once a day. It also does not interact with other medicines or birth control pills, and manifests less drug resistance than other AIDS medications.
Monkey studies show exciting results
A major study by the CDC (Centers for Disease Control and Prevention) in Atlanta, Georgia involved six macaques. The monkeys were given a combination of Tenofovir and FTC and then administered a deadly combination of monkey and human AIDS viruses. They were given the viruses in rectal doses to simulate contact between gay men.
Each was given 14 weekly exposures of the virus, and none of the monkeys became infected. In a control group which did not receive the drugs, all but one got the disease, normally after just two exposures.
The scientists then stopped giving the drugs to the test group to see if the prevention was only temporary. The results were equally impressive. None of the monkeys contracted the disease. "We're now four months following the animals with no drug, no virus. They're uninfected and healthy," reported a CDC researcher.
Now other research teams are pushing to have this drug combination tested on humans. A $29 million CDC study of drug users in Botswana will now be switched to this new drug combination.
Another study of 400 heterosexual women in Ghana by the Family Health Initiative, and funded by the Bill and Melinda Gates Foundation, is studying the effects of tenofovir alone.
But several other studies have failed to materialize because studies of this nature immediately raise suspicions that scientists are using local people as guinea pigs. The fear is that they will intentionally expose the test subjects to the virus.
The cost of tenofovir and Truvada also make testing difficult. In African countries condoms are now liberally donated by companies, aid groups, UN agencies, and western governments. While the drugs are relatively cheap, the cost remains an impediment.
Nevertheless researchers have been reinvigorated by the stunning results out of Atlanta, and new tests are going ahead in pockets of interest around the world.