“Breakthrough of the Year”—Treatment as Prevention
In what Science magazine in May called the “Breakthrough of the Year,” a clinical trial known as HPTN 052 showed that relatively healthy people living with HIV who received early treatment with ARVs were 96 percent less likely to pass on the virus to their uninfected partners. “This new finding convincingly demonstrates that treating the infected individual—and doing so sooner rather than later—can have a major impact on reducing HIV transmission,” said National Institute of Allergy and Infectious Diseases (NIAID) Director Anthony S. Fauci, M.D.
A CDC study found that a once-daily antiretroviral tablet reduced the risk of acquiring HIV infection by roughly 63 percent overall in a population of uninfected heterosexual men and women. The strategy of providing daily oral antiretroviral drugs to uninfected individuals prior to HIV exposure is called pre-exposure prophylaxis, or PrEP. A previous study—the results of which were announced in 2010—had already shown PrEP reduced HIV transmission among men who have sex with men, but it was not previously known if the strategy could prevent HIV infection among heterosexuals.
New Therapy Mimics HIV-Resistant Genes
Sangamo BioSciences, Inc. developed a gene therapy technique that mimics a naturally occurring, but rare, human mutation in the CCR5 gene that renders individuals largely resistant to contracting HIV. The therapy involves removing CD4 cells from patients’ blood and then transplanting HIV-resistant, genetically modified cells back into the body. After undergoing the treatment, six patients showed a drop in the level of HIV in their blood, without taking antiretroviral drugs. The central role of CCR5 in HIV infection was discovered by amfAR grantee, Dr. Nathaniel Landau.
A Boost for Cure Research
The National Institute of Allergy and Infectious Diseases at the National Institutes of Health funded its first large-scale round of grants to support collaborative research toward a cure for HIV/AIDS. The grants were given to three research teams that included several current and former amfAR grantees and totaled more than $70 million over a five-year period.
A Microbicide Trial Disappoints
A trial evaluating an ARV-based vaginal gel microbicide for preventing the sexual transmission of HIV in women was halted after a routine review of study data concluded that the gel was not effective in preventing HIV in the participating women from Uganda, South Africa, and Zimbabwe. The review showed that there was no difference in effect between the placebo gel group and the ARV gel group. These data were surprising given results from the CAPRISA trial 6 announced in 2010, which showed 39 percent fewer infections among women who received gel containing the ARV tenofovir compared to women who received the placebo.
Vaccine Efficacy Undermined
Researchers found a potential explanation for the surprising results of a 2008 study that showed an increase in the number of HIV infections in those who received a candidate HIV vaccine. The vaccine tested in 2008 uses a common virus, adenovirus type 5, to deliver the vaccine into cells. This new study revealed that individuals with large immune responses against the vaccine delivery virus, presumably resulting in the killing of the virus and the vaccine it contained, generated a weaker response to the vaccine than those whose immune system did not destroy the vaccine. According to the report, these findings provide “a new understanding of how preexisting viral immunity may impact the efficacy of vaccines under current evaluation for prevention of HIV, tuberculosis, and malaria” and will guide future efforts to develop more effective AIDS vaccines.
Disrupting the HIV Life Cycle
A protein that inhibits an early step of the HIV-1 life cycle in immune cells was identified by Dr. Monsef Benkirane of the Institut de Génétique Humaine in Montpellier, France, and his colleagues. (The protein was also independently identified by current amfAR grantee Katarzyna Hrecka, Ph.D., of Case Western Reserve University and her collaborators.) This important finding, published in May in the prestigious journal Nature, advanced understanding of HIV pathogenesis and may be useful for the development of an HIV vaccine.
Contraception and Increased HIV Risk
A study of nearly 3,800 serodiscordant couples (in which one partner is HIV positive and the other is HIV negative) in seven African countries found that women using hormonal contraception, a shot given every three months, had double the risk of acquiring HIV. Women who were HIV positive at the beginning of the study and using hormonal contraception were also twice as likely to transmit the infection to their male partners. There was some suggestion, but not definitive proof, that these findings might also extend to the use of oral contraceptives.
HIV and Organ Transplantation
A study published in June in the American Journal of Transplantation revealed that HIV-infected deceased organ donors represent a potentially novel source of organs for HIV-infected transplant candidates that could decrease waitlist deaths and even shorten the national waitlist. The results showed that organs from approximately 500 HIV-infected, but otherwise healthy, deceased donors per year are discarded due to a federal ban on the transplantation of HIV-infected organs.
amfAR Grantees Begin Cure-Focused Clinical Trial
Two researchers funded by the amfAR Research Consortium on HIV Eradication (ARCHE), Dr. Robert Siliciano and Dr. Steven Deeks, began recruiting patients for a cure-focused clinical trial. They
hope to determine if a drug already approved by the FDA for the treatment of
another condition will help flush the virus out of latently infected cells and,
in combination with antiretroviral drugs, reduce the latent reservoir of HIV in
the body over time.