HIV/AIDS Vaccine To Begin Phase I Human Trials 329
An anonymous reader writes "An HIV/AIDS vaccine developed in Ontario has applied for Phase 1 human trials. Safety and immunogenicity studies of the vaccine, dubbed SAV001-H, have already been completed on animals. Phase 1 human trials will check the safety of the vaccine on HIV positive volunteers. Phase 2 will then test immunogenicity."
Re:Is this it? (Score:5, Informative)
Just a side note since a lot of discussion on HIV and AIDS. HIV is the virus, the virus attacks the immune system destroying your white blood cells, when your white blood cell count falls below a certain amount per 1mm of blood or some measurement you have AIDS or auto-immune deficiency syndrome caused by HIV.
The virus wont kill you, what will kill you in the end is a basic infection that your body cant handle, even the common cold.
It's just phase I testing (Score:5, Informative)
Don't get too excited. A few other promising AIDS vaccines have made it this far. Phase I testing is just testing for safety, not effectiveness. Phase II testing is for effectiveness, and phase III testing is for effectiveness in a larger population. VaxGen's vaccine made it to Phase III before it turned out not to be very effective. 95% of the new drugs that make it to the beginning of testing in humans don't turn out to be useful.
Re:how do you test it? (Score:3, Informative)
Presumably this is a therapeutic vaccine intended to equip the immune system to fight HIV before it trashes your immune system irreparably. I didn't bother to read the article (but I was able to finish the summary) so I wouldn't really know.
Re:No Optimism on HIV (Score:3, Informative)
Unfortunately (OK, it's not unfortunate at all, actually), option #1 isn't just taboo, it's impossible in any human society. Even if we had a completely accurate test (which we certainly do NOT have), and even if you could somehow prevent all positive contacts from continuing their infectious behavior (and I'm not sure anything short of summary execution would be reliable), you'd still have leakers, avoiders, corruption, and resistance. Not even North Korea has managed to avoid HIV, although they're close, at least by report. Largely, I suspect, because summary execution is a routine thing for them.
Option #2 is science fiction for now. The genetic resistance to HIV is conferred by the lack of a particular cell-surface receptor, so you'd have to find a way to effectively eliminate that piece of genetic material from every genome in the body. And since T cells are quite long-lived, you'd have to mess with a lot of quiescent DNA to do it. Maybe some day, but not soon.
Which leaves vaccination. I'm in agreement with your skepticism on this one, not because it's impossible but because HIV, due to its unique targeting system, has been very intractable. You do have to target relatively stable regions of its proteins or its DNA, but this isn't unique to HIV, and we've solved it with polyvalent vaccines elsewhere (think Menactra, or the recent HPV vaccine, or even the flu shot). HIV is a pretty wimpy virus from a spread perspective, so a good polyvalent vaccine would seem possible. The problem is practical immunogenicity, and that's the issue that has torpedoed previous vaccines.
Re:how do you test it? (Score:1, Informative)
No there is no prerequisite like that.
Here's how the studies typically work.
1. Locate a country that has an extremely high HIV prevalance (some countries in Africa have 20% or higher HIV rates) .. because statistically half of them will get he placebo so it will not hurt the study).
2. Advertise for a few thousand prostitutes and IV drug users and other high risk people to participate (even if some non high risk people come no big deal
3. Offer adequate compensation for participation in the study
4. Inform each particpatant equally and thoruoghly about the dangers of risky sex
5. Stress that being vaccinated may not protect them and that furthermore they may be getting a fake injection (termed a placebo).
6. Innoculate half (or whatever) of the participants with the vaccine, the other half get a bogus injection (the placebo).
Human nature is such that no matter how sincere and good faith your effort was to inform them of the risks of HIV, many of the participants will still go out and have risky sex.
7. After 1 or 2 years test the participants in the study. If the vacccinated group has significantly less HIV positive people than the ones from the placebo group .. you vaccine works. If there is no statistical difference .. your vaccine's a dud. If the placebo group has less HIV positive people (like what happened in a recent study) .. then yikes your vaccine increases the risk.
Re:how do you test it? (Score:5, Informative)
Re:Which is It? (Score:3, Informative)
I would use my mod points to help you, but I think it's best to post a reply telling future moderators that the above is not a troll. That is what I thought before clicking the link. This is in fact a post spreading the awareness of child abuse in South Africa (at times resulting in gang-rape of an infant) because of the foolish and terrible myth that having sex with a virgin infant can cure your AIDS. Click on the link and help with the petition if you are interested
Re:Which is It? (Score:2, Informative)
Of course not. No more than the common cold is the same thing as the enterovirus that causes it.
Common cold is most commonly caused by rhinovirus.
Re:Is this it? (Score:2, Informative)
This is a phase I test.
The huge one is phase III
http://www.iavi.org/RESEARCH-DEVELOPMENT/DEVELOPMENT-CYCLE/Pages/review-process.aspx
Other vaccines passed phase I and failed after that.
These are good news because scientists doesn't start human trials if they don't feel good about the vaccine developed but it isn't the time to celebrate yet.
Re:how do you test it? (Score:3, Informative)
If I take the vaccine and I only sleep with my wife and in 10 years I'm HIV free does it work?
Or is one of the pre-requisites of joining the trial that you commit to sleeping with as many sleeezy whores as you can find?
Wouldn't that also depend on how sleazy of a whore your wife is over those 10 years?
Re:Is this it? (Score:4, Informative)
Except that the kids can't help that their parents are thick as bricks.
Re:What kind of injections? (Rim shot) (Score:3, Informative)
A vaccine is usually a weaker version of the original virus, right?
If HIV is spread sexually, does the vaccine spread sexually as well? This really puts a wrench into sex education.
No, a vaccine is usually a DISABLED version of the original virus - one that has the protein coat that the immune system would use to recognize and create antibodies for, but has the part that creates copies of the virus disabled so it can't make any more to overwhelm the host or to spread.
Re:RTFA (Score:3, Informative)
No, it isn't, but it IS safe to assume that YOU are ignorant of the situation in Africa.
A lot of people there ACTUALLY BELIEVE having sex with a virgin will cure you. Or that you're supposed to cut the tip off of the condom.
Education has to be the priority there.
Re:Test on (Score:2, Informative)
Re:how do you test it? (Score:1, Informative)
You guys modded this informative? No one will EVER do this!
Re:Is this it? (Score:5, Informative)
A few points;
1: While you can inject the HIV virus into other animals, the virus will not enter their cells due to the variations between human CD40 and the animals' copy. They can get the virus in them, but it won't do anthing.
2: There are animals whose cell surface ligands are similar enough to the human ones that the virus *does* infect them. if I recall correctly, HIV is capable (though much less efficiently) of entering the cells of certain apes, cats, and armadillos (an eclectic combination to be sure).
3: Of those animals that will play host to the virus, none of them develop symptoms of AIDS. They will host the virus, spread it around, but will not suffer immunoinhibition. This really isn't that uncommon; humans carry several viruses with no measuarble histological effect. This means that there are no suitable animal models for vaccine testing; human testing really is the only viable option.
4:It has long been theorized that the difference between being HIV positive and having AIDS is merely the amount of virus spreading in the system. i.e. if you can keep the viral load low enough, you won't get AIDS. If this is indeed the case, then even a therapeutic vaccine will be a huge step forward in the mortality rates of those infected.
5: Yes, HIV mutates quite quickly. For this reason, the approach that has long been favored is a competitve virus that targets the same cell types as HIV, yet does not have the same level of virulence (a latent infection rather than an actively spreading one). This is the same strategy employed with polio; the original polio vaccine was an actively spreading infectious virus that simply didn't cause the same disease symptoms. It also spread from person to person just like the disease it was meant to treat. This "similar but safer" strategy is likely the only way to have the 'treatment' evolve quickly enough to keep in step with the target. This is also the most difficult type of vaccine for which to acquire testing approval (for obvious reasons).
6: Other vaccine types are much less likely to be effective against a quickly mutating target like HIV. While they may prime the immune system effectively enough against a single strain of the virus, it's much less likely to work against other strains (same reason that you have to get the flu shot every year rather than just once).
7: It was recently shown that HIV can spread through cell:cell junctions. This being the case, it is unlikely that typical vaccines (other than live virus) will be effective, because there is no chance for antibodies (the typical immune system mediator) to interfere in this infection process. Now, it is unlikely that cell:cell spread is sufficient to get viral load to the point of causing AIDS, but it is still a factor to be considered when making predictions about vaccine efficacy (viral clearance is extremely unlikely).
8: This is a phase 1 trial. It's a small scale trial where they're testing for toxicity, not efficacy (phase 2/3). In other words, this trial is designed to answer the question, "is it safe?" It will not answer the question, "does it work?"
Re:How does this work? (Score:4, Informative)
HIV mutates a lot, but a whole lot of that is thought to be stochastic mutation. The most basic version of this would be where type A becomes type B, but type B also mutates back into type A just as fast, so after a few dozen generations, the population reaches an equilibrium, half of each type. The point is, it's not evolutionary mutation - you have the random mutation part, but until there's some sort of selection pressure, you don't have evolution. There's a difference between having to deal with non directed mutation (which is what stochastic means in this context) and actual evolution. HIV mutates a lot - HIV is NOT evolving rapidly.
HIV appears to have four types (in this case, of outer protein coats) which are usually called A, B, C & D, but again, nothing is selecting for one type over the others and there's theoretically no pressure for HIV to evolve because of this particular mutation. Some flus have a lot more than four types. Right now, the swine flue that has people worried is type H1N1, and there are six or seven types just for the N part of that classification, and maybe 30 or so total type combinations possible.
A highly effective vaccine in this case would probably require it make the body's immune system target some part of HIV's protein coat that doesn't usually mutate, just so it doesn't have to fiddle around dealing with the cycle of forward and backwards mutation.
Re:how do you test it? (Score:3, Informative)
One of the studies we're doing in my lab is an intervention with (currently) HIV- youth who engage in frequent risk behaviors (most are sex workers, a little under a third are IV drug users, a very small portion just have risky sex because that's what they do). As part of the study, we do HIV testing every 3 months. We have an "expected" rate of conversion (obtained from other studies) and then we compare our actual rate of conversion to see whether our intervention is having an impact. While I'm no biostatician, I imagine the process is similar for a vaccine trial as for an educational intervention - you get people who are extremely likely to convert, vaccinate them, and if fewer convert (hopefully none of them!) despite engaging in risky activities, you can say that there's very likely been an effect.
Re:Test: How? (Score:2, Informative)
Re:Which is It? (Score:2, Informative)
It seems that it is possible. I don't know if this vaccine works that way, but a couple years a story got posted on slashdot about a compound that "could not only inoculate the patient against future infection, but destroy an HIV infection in progress.":
http://science.slashdot.org/story/07/07/22/0437213/HIV-Vaccine-Ready-For-Clinical-Trials [slashdot.org]
Re:Which is It? (Score:2, Informative)
While your statement is technically correct, vaccines can and do help with existing conditions as well:
http://en.wikipedia.org/wiki/Vaccination [wikipedia.org]
"Some modern vaccines are administered after the patient already has contracted a disease, as in the cases of experimental AIDS, cancer and Alzheimer's disease vaccines. Vaccinia given after exposure to smallpox, within the first four days, is reported to attenuate the disease considerably, and vaccination within the first week is known to be beneficial to a degree."
My father - who is a doctor - has confirmed this to be true. Apparently some infections (not only HIV, any infection) ARE treated with a vaccination, although it is not the only part of the treatment.