New Vaginal Gel Prevents AIDS Virus Transmission
webmd.com
webmd.com
http://www.sciencedaily.com/releases/2009/03/090302183124.ht...
"...SIV shares only about half of its amino acid sequence with HIV, making it a very imperfect substitute for testing anti-HIV drugs and vaccines."
Also, it uses "devices" (odd name for a gel...ain't medicine fun?) that are already approved, so the time to market can be greatly reduced.
What they say essentially is "This is just another yellowish PR puke. You will never hear from us again. Thank you."
There is a huge uphill battle for getting something like this approved for use in humans and a large part of that is proving that the device is safe as well as effective. Firstly, we don't even know that this compound will work against HIV, since they tested it against SIV. Secondly, the gel is something would have to be applied to the vagina very frequently (think: sex workers) without causing problems (ie inflammation) that could make infection more likely. Additionally, the researchers showed that the gel is effective in very controlled settings-- will it remain effective during intercourse? Finally, I am not even sure how you ethically do the controlled study in humans to prove the gel's efficacy. It will have to be designed very carefully, for sure.
I am sure there are many other challenges to bringing this to market that I am not thinking even of, but they will get there, and I don't think this first result is insignificant.
First, a small-scale phase-I trial is done on otherwise healthy people -- they're just looking for safety, not efficacy. Any indication that the drug makes things worse, or causes significant health problems, and the drug is dead.
Once it's established that the candidate drug doesn't make matters worse, test groups of high-risk individuals are selected from the population: IV drug users, homosexuals with a history of unprotected sex, etc. They're selected for as much diversity/balance of demographic data as possible, then randomly divided into groups by the clinical trial organizer. The participants are given extensive counseling on HIV prevention, condoms, safe sex, etc.
The groups are then used to construct a double-blind trial, where neither the patients nor the physicians are aware of who is given placebos. Outcomes are continuously monitored, and if there's any indication that the drug raises incidence of HIV, the trial is terminated early.
I'm curious because my impression is that most drug trials have been for AIDS treatments (where, perhaps, placebos are more ethically acceptable-- especially before the treatment is known to be better than the placebo) rather than HIV prevention.
I'm not an expert on the ethics, but pretty much every vaccine trial faces this dilemma. The solution is to make sure that the trial participants are fully informed (i.e. they've got to know that they may not be getting a real vaccine), and to make sure that the vaccine in question doesn't make things worse.
If you can do those two things, then in the worst case, the participants are no worse off than if they hadn't participated in the trial at all. But as I said, clinical trials for things like HIV vaccines tend to go above and beyond, and do things like safe-sex counseling for every participant.