HIV infections halved by gel treatment
By Andrew Jack in Vienna
Copyright The Financial Times Limited 2010
Published: July 19 2010 16:43 | Last updated: July 19 2010 16:43
http://www.ft.com/cms/s/0/0ce17c1a-9343-11df-96d5-00144feab49a.html
A gel applied by women before and after sex has reduced the risk of HIV infection by more than half, according to experts briefed on a ground-breaking study to be released on Tuesday that could help revolutionize prevention.
Findings of the so-called Caprisa study, conducted in 900 women in South Africa, show for the first time the potential of a microbicide applied to the vagina to sharply cut infection.
The research – which will still require substantial analysis and several years before it could lead to widespread applications - marks the first time that a product containing an antiretroviral drug used for treating HIV has been successfully applied to prevention.
Several earlier studies with alternative microbicides have proved unsuccessful.
It signals a boost to Gilead, the US pharmaceutical company that developed the drug, known as Tenofovir, and will help the demoralised research community regain confidence, after setbacks with a series of other microbicides and HIV vaccines.
A second approach to using Tenofovir for prevention is in the form of a pill for those at high risk of HIV infection. Safety findings are also set to be released at this week’s International Aids Society conference in Vienna, although efficacy data will only be published later in the year.
The results also mark a particular fillip for South Africa, which has one of the world’s highest rates of HIV but was involved in both conducting, designing and funding the trial.
The journal Science is due to release the full findings on Tuesday but two people breifed on the study said it showed that in patients who took the microbicide consistently, it cut HIV infection by 39 per cent, rising to 54 per cent among those who were consistently using it in line with instructions.
While the speed of new HIV infections has been slowing since the start of the decade, the United Nations estimates 2.7m people are contracting the virus for the first time each year, adding to 33.4m already infected.
Aside from abstinence and use of condoms, circumcision is the only new approach to cutting HIV infection that has been proven to work in the last few years and which is now being offered in a number of high risk countries in Africa.
Before the microbicide could be used widely, it will have to undergo far more extensive late-stage clinical trials for safety and efficacy, and pass scrutiny by regulators. There will also need to be consideration of how best to market it and ensure it is used consistently in order to provide the maximum protection from infection.
One concern is that widespread use of the drug for prevention could jeopardise its potential for treatment by increasing the chance of HIV developed resistance to the medicine. Tenofovir is part of the cocktail of drugs most widely used in the developed world and is becoming increasingly common in patients in poor countries.
There could also be substantial costs in making the microbicide widely available.
Speaking on Monday ahead of publication of the Clarisa results, Bill Gates, the businessman and philanthropist, said he would work to ensure that funding was not an obstacle to the use of tenofovir in prevention if it proved effective. But he warned it could still take several years even if was proved safe and effective in microbicides or as a pill, because of regulatory, manufacturing and marketing hurdles. He also cautioned of the risks of “disinhibition” - that those taking such approaches to prevention could feel protected and participate in activities putting them at high risk of infection.
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