Drugs May Offer AIDS Prevention

FlipFlopSnowMan writes "There is an interesting article on MSNBC about the possibility of preventing AIDS using the same pills that are currently used to fight the virus in affected individuals." From the article: "The drugs are tenofovir (Viread) and emtricitabine, or FTC (Emtriva), sold in combination as Truvada by Gilead Sciences Inc., a California company best known for inventing Tamiflu, a drug showing promise against bird flu. Unlike vaccines, which work through the immune system -- the very thing HIV destroys -- AIDS drugs simply keep the virus from reproducing. They already are used to prevent infection in health care workers accidentally exposed to HIV, and in babies whose pregnant mothers receive them."

Comments

Cash cow?

[Tx]

Q. How to make more money from expensive AIDS drugs?

A. Obvious - sell it to people who don't have AIDS as well as people who do.

As I understand, these drugs are very expensive, and personally I can't see any justification for using them prophylactically.

Re:Cash cow?

[Saulo Achkar]

...personally I can't see any justification for using them prophylactically. Get AIDS and you will find a justification....

Re:Ah, man..

[dario_moreno]

"odds are 1 in 10000"...rather 1 in 1000, and even more for receptive sex, and if you do it once a day, you get almost a 1 in 2 chance of catching it after 500 days. Check Chad Douglas on google...always on top, positive after 5 years, dead after 15.

Ummm...

[spaztik]

This is all well and good but...

In the United States, wholesale costs are $417 for a month of tenofovir and $650 for Truvada.

Who is going to be able to afford this stuff?

Terrific Idea

[scrub76]

The evidence that AIDS drugs can prevent infections comes not only from exposed health care workers, but also monkey studies. If monkeys are given AIDS drugs up to 48 hours before exposure to SIV (the causitive agent of simian AIDS), they fail to become infected. That has been known since the late 90s. There is some data suggesting that the drugs can't always protect against multiple exposures to SIV, but those studies used only one drug at a time (not a cocktail of pills, like you would take if you had HIV).

As an HIV researcher myself, I realize that we are not going to have a highly effective, preventative vaccine for HIV any time in the near future. There are no clear 'winners' in the pipeline right now, and even if a vaccine looked effective right now, it would be years (and millions of new infections) before it clears human testing and it broadly available. Issues like viral resistance to the vaccine, incomplete protection from infection, potential side effects, and a false sense of security would plauge any vaccine that is developed -- and these are many of the same issues confronting the use of drugs as HIV preventatives.

One major hurdle to testing these drugs in populations highly affected by HIV is to convince them that this intervention is not a magic bullet. There will be problems, some of which we probably can't predict. There will be breakthrough infections in people taking the drugs. And the long-term health consequences aren't known. So far, these concerns have led to the abandonment of several trials of PrEP (using tenofovir in HIV-, high-risk populations) around the world. Hopefully the new data (using multiple drugs together works better than tenofovir alone) will encourage vulnerable populations that the potential benefits may outweigh the risks.

What to expect.

[sammy baby]

Expect immediate, heavy resistance from the ultra-right wing, Christian conservative political forces in the US. Experience has shown that if there's a disease that increases the potential negative consequences of having sex, especially those which disproportionately affect women, they will oppose efforts to provide treatment. (Women in heterosexual relationships carry an increased risk of HIV transmission when compared to men, although they have a decreased risk in homosexual relationships. The reasons I leave as an exercise for the reader.)

Case in point: the human papilloma virus, or HPV. Now here's the thing with HPV: it's sexually transmitted, condoms don't protect against it, and doctors believe that it's responsible for seven out of ten cases of cervical cancer later in life. So, if we could develop a vaccine against it, that would be a huge strike against cancer, right?

Well... sure. But ultra right groups like the Family Research Council oppose such a vaccine, even though pharmaceutical companies have already conducted successful clinical trials. Why? Because they want to scare people into not having sex.

"Giving the HPV vaccine to young women could be potentially harmful," Bridget Maher of the Family Research Council told the British magazine New Scientist, "because they may see it as a license to engage in premarital sex."

If this is the reaction an HPV vaccine (or, for that matter, condoms) gets, how do you think they're going to react to a cure to something which disproportionately affects gay men?

face the facts

[penguin-collective]

what if one of the various "environmental factors" models is right rather than the "single pathogen" model?

That's just not a serious possibility anymore; here are just some basic observations:

• While clinical diagnosis relies on symptoms, HIV infection has been followed in minute detail from initial transmission to death numerous times, in the presence and absence of treatment, in individuals with completely different histories, at the molecular level, at the tissue level, and at the clinical level.
  
• The epidemiology of HIV has been studied extensively: the disease is clearly transmissible and no other factor than an existing HIV infection is associated with transmission.
  
• Drugs specifically targeted at HIV have increased survival rates tremendously, while changes in lifestyle have had limited effect.
  
• The molecular mechanisms of resistance to HIV infection (found in a few percent of the population) are well understood.
  

Single pathogens are sexy for epidemiologists.

Yes, and they are also the rule for infectious diseases. While susceptibility and severity of a disease may vary with environmental factors, for infectious diseases, there is usually a well-defined, clearly characterizable pathogen responsible.