Treating to Prevent HIV

posted: 03/03/2011

Could people who do not have HIV use HIV treatment drugs (PrEP) to stop themselves from getting HIV? The detailed results just out for gay and bi men are better than the early findings. This means PrEP could be approved for use in the USA by the end of the 2011.

Last year, the first results from a study of gay and bisexual men appeared. Taking PrEP cuts gay and bi men’s risk of getting HIV. But there were worries because many of the men did not take all the tablets. Some men got HIV.

HIV infection
Much better updated results were announced at the CROI conference in Boston, USA, that has just ended.

In the different places where the trial took place, including South Africa, the taking of PrEP (HIV drugs to prevent HIV infection) varied a lot.

Gay and bi men in the two USA cities (Boston and San Francisco) of the international iPrEx study of tenofovir/FTC (Truvada) had near-perfect HIV-prevention drug taking, compared with 50% tablet taking at the other sites.
 

And the men taking the greatest sexual risks for HIV, by having unprotected receptive anal sex, were taking the prevention treatment better than men taking less HIV risks – which is good to know.
 

USA approval within a year?
Lead investigator Bob Grant announced that the US Food and Drug Administration (FDA) had agreed that the trial results were good enough for the FDA to consider allowing the use of Truvada to prevent HIV. PrEP, as a result, might be approved in the USA by the end of this year.
 

First USA Guidelines for gay men published

Interim Guidance: Pre-exposure Prophylaxis for the Prevention of HIV Infection in Men Who Have Sex with Men from USA Centers for Disease Control and Prevention. 

2500 men and the results

There were almost 2500 men in this trial and 130 of them got HIV by the end. Like most drug trials men were randomly split into two groups and told they would either get Truvada, or a dummy pill, but no-one would know who was taking what, until the end. The men were therefore warned they should still use condoms, because half were using the dummy pill.
 

48 of the men who got HIV took the Truvada and 82 of the men who were taking the dummy pills, a HIV infection rate of 2.6% a year. Another 10 other men have HIV, but they already had the symptoms of HIV infection when they joined the study.
 

This means that the final ‘how well does it work’ rate in the ‘modified intent to treat’ analysis, (this leaves out the 10 men who started the study with HIV, and ignores things like different rates of tablet-taking and the men’s level of sexual risk-taking), was 42%.
 

PrEP worked better when men were over 25 (56%), among men who took more than 9 out of 10 of the tablets (68%), and among the men who were circumcised (76%).
 

Would PrEP be cost effective? 

Other new studies have now looked at the value for money of treating people to prevent HIV in South Africa. The answer is mixed. 

It is usually cheaper to treat the person with HIV than treating one or more HIV negative people with PrEP. Treating the person with HIV should reduce their viral load so it becomes undetectable and their chance of passing on HIV then becomes very small. In mixed status couples, that may be enough protection for many. But PrEP would help protect negative partners who have unsafe sex outside the main relationship and who don't use condoms.  

Source and more details

USA Prevention Treatment Gay Guidelines

posted: 08/02/2011

The first guidelines for HIV negative gay and bisexual men wanting to reduce the risk of getting HIV by using the anti-HIV drug Truvada have appeared.

Taking HIV treatment drug(s) before sex is called pre-exposure prophylaxis (PrEP) and it is not guaranteed to work.

Just two months after the first positive results showed that Truvada can sometimes help, this ‘interim guidance’ has very quickly appeared.
 

The USA public health body, the Centers for Disease Control (CDC), were worried that unofficial, poor use of Truvada and bad habits would grow up if they didn’t put out some guidelines quickly.
 

Prescriptions with detailed support
In the guidelines prescriptions should only be given for 90 days at a time, with HIV testing, adherence counselling, sexually transmitted infection check-ups, sexual risk counselling and condoms provided before new prescriptions are issued.
 

Only if HIV risk ‘substantial’ and continuing
The guidelines state that PrEP should only be provided for men who have sex with men, specifically those who are “at substantial, ongoing, high risk for acquiring HIV infection”.
Pre-exposure prophylaxis involves HIV-negative people taking antiretroviral medications in order to reduce their risk of acquiring HIV. In November, a study conducted with gay and bisexual men in six countries showed that daily use of the two drugs tenofovir and FTC (combined in one pill as Truvada) reduced the risk of infection by 44%.
 

However many of the gay and bisexual men participating in the trial did not take the pills each day, as prescribed. In men who did take the drugs consistently, results seemed to be much better. In men with very poor adherence, results were worse.

However extensive analysis of the adherence data from the trial has not yet been completed, nor have the trial results been replicated in other settings.
 

The CDC only supports using Truvada when it is used almost exactly like it was in the trial. That is why they are limiting its use now gay and bisexual men at high risk of getting HIV.
 

Truvada indicators
The guidance gives quite a broad indication of which men PrEP may be suitable for, citing only lack of condom use in combination with “frequent partner change or concurrent partners in a geographic setting with high HIV prevalence” as examples.
 

Truvada only
The CDC says that antiretrovirals other than Truvada should not be used for PrEP and that the same daily dosing schedule that was employed in the trial must be followed. Therefore, ‘intermittent’ dosing (i.e., before or after sex) is not endorsed.
 

Adherence and continuing prevention support
Moreover adherence support must be a “routine component of any PrEP program”. It should be provided before PrEP is issued, and then at least every 90 days.
 

Similarly, PrEP should only be delivered “as part of a comprehensive set of prevention services” that includes risk-reduction counselling, ready access to condoms and the diagnosis and treatment of sexually transmitted infections. These activities should take place each 90 days, before a new prescription is issued.
 

HIV test first
Before PrEP is provided, clinicians must also check that the patient is HIV-negative. If he has any signs or symptoms that may be linked to HIV seroconversion, RNA testing is recommended. He must also be screened for sexually transmitted infections and hepatitis B, and have his kidney function assessed (Truvada can sometimes harm the kidneys).
 

Other tests for side-effects are required after three months and then annually. Any serious adverse events should be reported to the Food & Drug Administration (FDA).
Cost will be a central concern. In the USA medical insurance companies are unlikely to pay for this prevention use of Truvada but if men have the cash USA doctors can prescribe it. A month’s supply costs around $1000, and USA patients would also have to pay for counselling, side-effects monitoring and doctors appointments.
 

Source

Smith DK et al. Interim Guidance: Pre-exposure Prophylaxis for the Prevention of HIV Infection in Men Who Have Sex with Men. Morbidity and Mortality Weekly Report 60: 65-68, 2010.