I am, in no way, a 'fan' of using anti-retroviral drugs in uninfected individuals as a way to prevent HIV. I think its a terrible idea that will result in more drug resistant HIV (already an issue before this idea was implemented) and ridiculous considering everyone who needs anti-retrovirals to live does not have/are losing access.
Condoms are a cheap, drug-free, side-effect free, effective way of preventing sexual HIV-1 transmission, and HIV-1 cannot evolve to be 'condom resistant'.
So you might be surprised to find out that I think that this is a good idea, and I hope it ends up working in humans:
An Intravaginal Ring That Releases the NNRTI MIV-150 Reduces SHIV Transmission in Macaques
These researchers used intravaginal rings to deliver an anti-retrovial drug to macaque lady parts. The macaques were then challenged with SHIV (part HIV, part the macaque version of HIV, SIV). In the untreated macaques, 11 of 16 were infected (69%). In the macaques that got the anti-HIV vaginal ring, 2 of 17 were infected (12%).
SCORE!!
"BUT WAIT!!" some readers might say. "I thought you were AGAINST using anti-retrovirals in uninfected people! Wont this just lead to drug-resistant HIV too???"
Apparently not. Of the treated animals that still got infected, they were not infected with a drug resistant variant. The viruses looked 'normal'.
How did that happen? Well, the drug is in the ring, and the drug remained concentrated in the vagina/cervix. The drug does not become systemic, so after the virus gets in, the drug is not a selective pressure.
So, either a drug resistant variant got in, and, because drug resistance usually comes at a fitness cost, it immediately reverted back to the wild-type sequence. Or, it was just a numbers game-- too much virus, not enough drug at the right place, and a wild-type virus cruised by the anti-retroviral 'block' and could establish infection.
But in either case, what we have is a female-controlled anti-HIV protocol that would not lead to drug resistance (meaning that the pre-HIV therapy wouldnt cut off potential HIV therapies, if infected).
After more investigation in non-human primates (we need to know why/how they are still getting infected), I really hope this ends up working in human females...
- Log in to post comments
A similar ring device, containing the experimental NNRTI dapivirine, is already being tested in human Phase III clinical trials.
http://www.ipmglobal.org/the-ring-study
The ring was initially developed in my laboratory at the Queen's University of Belfast, Northern Ireland, and is being progressed through clinical studies by the International Partnership for Microbicides. First results are due 2014.
It is worth nothing that drug does reach with the systemic compartment with these rings devices, although concentrations are very low.