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In New Study, HIV Prevention Pill Truvada Is 100% Effective
An anonymous reader writes: A study published in the journal Clinical Infectious Diseases details the recent trial of a drug named Truvada, which researchers think might excel at preventing HIV infections (abstract). The scientists administered the drug to 657 people at high risk for contracting HIV, including users of injected drugs. At the end of the study, every single subject was still free of the virus. This is encouraging news in the fight against AIDS, though it shouldn't be taken to mean the drug is perfectly effective. Since researchers can't ethically expose people to HIV, we don't know for sure that any of the subjects were definitely saved by the drug. Other studies have also had to be stopped because it was clear subjects who were on a placebo were suffering from noticeably higher rates of infection. Leaders in the fight against AIDS say this new study closes a "critical gap" in existing research by demonstrating that Truvada can work in real-world health programs.
The scientists administered the drug to 657 people at high risk for contracting HIV, including users of injected drugs. At the end of the study, every single subject was still free of the virus.
Can anyone who can view more than the abstract tell me how many they would normally expect to contract HIV?
Nevermind, buried in the NYT article:
That amounts to 388 “person years” of observation.
By contrast, in a 2014 clinical trial among gay men in England, participants who received a placebo instead of Truvada had nine infections for every 100 person years of observation, said Dr. Anthony S. Fauci, the director of the National Institute for Allergy and Infectious Diseases.
So assuming similar populations 388 * 9 / 100 = ~35, of course I'm too lazy to compute the confidence intervals.
I stole this Sig
As someone who is gay, I have done a fair bit of research in to HIV, the way people become infected, treatments, preventative measures, etc. I am not HIV positive, so perhaps not as much research as someone who is HIV positive... but in being gay, HIV is a topic that pops up. I am not a biochemist, but I know the basics.
Truvada IS one of the drugs you can take if you become infected with HIV. If you are HIV positive, it works in combination with other drugs to prevent the virus from replicating itself. It inhibits some process the virus uses to attach to other cells in order to get the cell to manufacture new copies of the virus. This means the virus is unable to replicate itself in your blood stream.
When you become HIV positive the virus also lives in parts of your body other than your blood stream. The HIV medications can't reach these locations so they just live there and it doesn't compromise your immune system for the virus to be in those parts of your body. Your blood stream is clear of the virus so your immune system operates more normally and can fight infections. But once you stop taking the drug, the component of the drug that inhibits its replication in the blood stream is no longer there. So the virus is able to then start replicating itself in your blood stream again and symptoms return.
Truvada as a preventative works because the virus can never gain a foot hold in your blood stream to make it to the other parts of your body it can live outside of the influence of the drug. If you get exposed to HIV while on Truvada, the virus just enters your blood stream, can't replicate, and it eventually dies.
At a 9% incidence rate (p=0.09), a 95% confidence interval would be 1.96 * sqrt( p*(1-p) / n ) = 1.96 * sqrt(.09*.91/388) = 0.02847, or 2.8%.
So you would have expected 35 +/- 11 cases.
A 99% confidence interval would be 3.7%, or 35 +/- 14.5 cases. So these are very promising results. Though converting 657 people to 388 person-years may be a bit suspect. Maybe HIV isn't detectable in some people after just a half year post-infection? And I'm not sure how the fact that a person can only be infected once skews the distribution (e.g. a sample of 2 people for 100 person-years has a maximum of 2 infections, while a sample of 200 people for 100 person-years has a maximum of 200 infections.)
Which version are you talking about? Catholics are very pro-sex. They want you to have lots of kids. It seems like liberal secularism is the death cult. With abortion, anti-children, and pro euthanasia. That why Western Europe is dying. It will be gone in a couple hundred years.
I love Jesus, except for his foreign policy.
People don't become resistant. Viruses become resistant. And that only happens AFTER infection, in the replication process. Prevent infection and you prevent the development of resistant strains. Treat HIV-positive people so they do not transmit their virus - a significant body of research and experience shows that HIV-positive people with undetectable viral loads simply do not transmit the virus - and give HIV-negative people effective tools for prevention, and resistance is a non-issue.
AFAIK, there are already commonly observed HIV mutations resistant to the these type of nucleoside reverse transcriptase inhibitors: M184V, M204V/I/S, L80V/I, V173L and L180M... Apparently, most of these mutations make HIV less virulent, but still able to reproduce. This is why these treatments are primarily aimed for PrEP (pre-exposure prophylaxis, or basically given to a high risk patient) because you are inherently less likely to get infected with these weaker mutated strains.
It also somewhat targeted at PEP (post-exposure prophylaxis, e.g., if you fear you have been recently exposed like you got raped or your partner fessed up about something), but not yet ill. Unfortunately, with the PEP regimen, if you have been exposed to a resistant strain, this NRTIs may not work as well (in the PrEP case the drug is already circulating in you blood when you are exposed), but of course given there is nothing else to do now, it's better to try these classes of drugs than do nothing. The only PEP cases that has been shown to be highly effective with these drugs is when HIV researchers get accidental needle sticks at work and of course they start take the drug immediately after exposure (not a few days later)...
For someone already with full blown HIV infection, they will currently need a cocktail of drugs to keep the virus at bay, these all-in-one pills like Truvada are not gonna do it for them... HIV is known to hide out and replicate/mutate outside the reach of the drugs we currently have and these NRTIs only attack one part of the problem.
That makes me wonder... Who the hell shares needles in this day and age? I no longer abuse opiates and was an IV drug abuser for years and years. Never, not once, did I share a rig with anyone. For two bucks you can get a ten pack. For twenty bucks you can find someone who gets insulin rigs regularly and buy a box of 1000 from them. I hadn't shot up much prior to the AIDS scare but I had and even then we didn't share rigs. I may have reused my own rig from time to time but sharing it? That's straight up retarded.
"So long and thanks for all the fish."
As part of its lifecycle, HIV integrates its viral DNA into the DNA of the cell it infects. In a normal infection, the viral DNA is then processed by the infected cell's own gene expression machinery and the virus starts to replicate. However, sometimes instead of the virus being expressed and made, the DNA is "silenced" by the infected cell, meaning the viral DNA is there but not being actively expressed by the infected cell. These cells then harbor the latent virus for as long as these cells are alive, which for some memory immune cells can be for the rest of your life. This is the virus reservoir. If you take anti-retroviral therapy (ART) drugs, such as the NNRTIs mentioned before or protease or integrase inhibitors, these will inhibit active viral replication, but won't cause any harm to the reservoir viruses that are latent. Randomly* as well, these "silenced" virus DNAs in infected cells that make up the reservoir can become un-silenced, and the virus will start replicating. If you are still taking ART, then nothing happens. If, however, you stop taking the medication, these viruses that pop back up will re-start the HIV infection and within a few weeks you will be HIV+ with viral loads (amount of virus in your blood) the same as before the ART treatment was started. This is why the ART medication must be taken for the rest of the patient's life, not because big Pharma wants to make extra cash.
Interestingly, if you follow patients that have lapses in their ART treatment and sequence the viruses that repopulate the infection, they become more similar (clonal) over time, due in part to the reservoir cells! Since potentially a single virus will do the repopulating from a reservoir cell, you would expect the resulting population of viruses to be more similar to each other than in the original infection, and this is what is observed: Specific HIV integration sites are linked to clonal expansion and persistence of infected cells .
* Random by measurement, not necessarily by mechanism.