Two European studies on pre-exposure prophylaxis (PrEP) of the finished randomized trials after its interim analyzes have demonstrated that in both cases the effectiveness of PrEP was so high that it would be unethical not available to all participants. AssaysPROUD e IPERGAY will continue, but with all participants taking Truvada (tenofovir / emtricitabine) as a preventive measure against HIV infection.
It is expected that the complete data are presented at the Conference on Retroviruses and Opportunistic Infections (CROI) in February, but it is expected that the trials have shown the highest levels of efficacy already observed in studies of PrEP.
The PROUD, study in the UK, provided the 545 gay men more vulnerable to HIV infection safer sex support package and half of these participants was immediately made available a daily dose of Truvada as PrEP, while for the other half the availability of PrEP was deferred for a year. The main objective of the study was to see if the behavior of risk for infection of the participants altered if they knew to be taking PrEP, but when an interim analysis prepared by the ethics committee and monitoring data (IDMB) showed a significantly lower number of infections HIV in people under PrEP, the decision was made to close the randomized phase of the trial on October 16.
However, in France and in Canada, the trial IPERGAY has tested a new intermittent PrEP regimen with 400 gay men. Participants were asked to take that a double dose of PrEP on before having sex and also in the two days after sex. Were randomized to take either Truvada or a placebo.
Spurred in part by PROUD announcement, IPERGAY of the IDMB also made an interim analysis and concluded that the effectiveness of the test system was so high that it would be unethical to keep participants on placebo. So it was announced on October 29 that Truvada would be made available to all participants.
Comment: It is important to anticipate the final values of the effectiveness of these studies, which will probably be presented at CROI in February, but it is already clear that this is a significant development in research on PrEP. The previous tests, although having a high effectiveness among people that really took also reported poor adherence, which impacts the effectiveness of the scheme. These seem to be the two first tests to demonstrate high efficacy at a general level, at least among gay men by that membership should also be high among most participants. This comes to suggest, more strongly than previous studies, that PrEP could be a practical and effective means of prevention among those most vulnerable to HIV infection and who are motivated to take.
This news gave rise to Community declaration by organizations working in the field of prevention in the UK, open to subscriptions, which require faster access to PrEP. Seehttp://www.prepaccess.org.uk to subscribe.
Progress in vaccines for HIV: New tests on humans in 2016?
A study in which it was given to South African volunteers RV144, the only regime in vaccine so far has shown some effectiveness in preventing HIV infection, found stronger immune responses among volunteers in this country than in the original study, in Thailand. A new study, HVTN100, which will begin in January, will administer the most South Africans a version of RV144 tailored specifically to HIV subtypes common in South Africa. If that produce stronger immune responses, an effectiveness study larger is planned for 2016.
The investigation of the immune responses of the participants of the Thai study to whom a boosted dose of RV144 was administered, eight years after the original study showed that the generated answers could only "neutralize" (ie, prevent infection of cells) the HIV strains that did not develop resistance to the human immune system attack. However, there are promising signs that were enhancers "push" the immune system of some of the participants toward the development of what is generally called neutralizing antibodies, they can disable most strains of HIV.
Another study in humans, which could start in 2016, will have smaller, will administer a vaccine involving HIV antigens (proteins signal) around another virus, CMV (cytomegalovirus). This vaccine does not prevent infection but does HIV infections, rendering them harmless, by ending these, in most cases, disappeared in the body. Sixty percent of a group of monkeys who were given the virus and then infected with the simian version of HIV (SIV) esttá now, three years later, free of infection and the experiences of this year will see if the vaccine, when administered to apes already infected with SIV, will result as a medicinal product, allowing them to stay healthy without antiretroviral therapy (ART). If this happens, the human clinical trials will begin in 2016.
Comment: The slow pace of vaccine development for HIV sometimes leads to doubt that this process ever ends. The slow process due to the fact that the HIV virus while preventing the normal immune response to viruses such as reproduction, is more bitter than other enemy subtle but relatively less developed viruses, such as Ebola. The development of a vaccine for HIV involves mainly new scientific knowledge and its complexity is comparable to a large space project. In any case, recent research continues to progress, either to improve existing approaches, such as RV144 either by random findings as CMV vaccine.