Prevention and Cure Steal the Show

Cure research hasn’t exactly been a hot topic at previous iterations of the International AIDS Conference (IAC). Things are different this time.

Thanks in part to the well publicized case of Timothy Brown—the only human ever to have been cured of HIV infection—a mini-boom in research toward replicating that feat and new funding for such efforts (see Stalking HIV’s Sleeper Cells, IAVI Report, March-April 2012), the subject finally took center stage at the sprawling IAC. “The research is quickly advancing,” said Javier Martinez-Picado, a scientist with the IrsiCaixa AIDS Research Institute in Spain, who delivered a plenary talk on Tuesday on cure research and its necessity—despite the effectiveness of antiretroviral (ARV) therapy in suppressing HIV.
 
“For every person who starts antiretroviral therapy, two others are infected with HIV,” said Martinez-Picado, adding that the cost of providing universal access to ARVs will be an estimated US$22 billion by 2015. “And the drugs don’t cure infection. At the end, we must have a cure for HIV.” 

Martinez-Picado noted that a global scientific strategy released by the International AIDS Society (IAS) and published this week lists seven scientific goals and six steps needed to achieve them (Nature ReviewsImmunology, doi: 10.1038/nri.3262 2012)
 
There were also some new developments on the microbicide front today. Researchers used the IAS meeting to announce the start of a Phase III trial in Africa this week evaluating a monthly vaginal ring containing the antiretroviral drug dapivirine. ASPIRE (A Study to Prevent Infection with a Ring for Extended Use) began screening volunteers in Uganda this week. When fully enrolled, it will include nearly 3,500 women from South Africa, Malawi, Zambia, Zimbabwe, and Uganda. 

The study is being led by the Microbicide Trials Network (MTN) and is being funded by the US National Institute of Allergy and Infectious Diseases and US National Institute of Mental Health. The ring, which contains 25 milligrams of dapivirine, releases the drug to cells in the vagina over the course of the month. This is the second current trial testing the dapivirine ring. 

The Ring Study, led by the International Partnership for Microbicides (IPM)—the developer of the dapivirine ring—has enrolled 400 participants at sites in South Africa since April and is expected to begin screening women in Rwanda in August. Total enrollment in The Ring Study will reach 1,650. Zeda Rosenberg, chief executive officer of IPM, said the dapivirine ring has a very good safety profile.
 
It was another microbicide—the 1% tenofovir gel—that energized the audience at the last IAS meeting in Vienna (see Microbicides Finally Gel, Securing Spotlight at the International AIDS Conference, IAVI Report, July-Aug. 2010). Results from the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 004 trial found that the gel was able to reduce HIV incidence in a group of South African women by 39%. 

However, there was some indication that adherence to the regimen waned over the course of the CAPRISA 004 trial. Adherence also remains a major concern for another promising intervention, daily pre-exposure prophylaxis (PrEP). Researchers from both vaginal ring trials said the ring might encourage more consistent use, which could help ensure effectiveness of the product. 

“If effective, this will really revolutionize prevention for women,” said Sharon Hillier, principal investigator of the MTN. Researchers hope to launch a separate trial soon that will combine an antiviral drug and a contraceptive in a single ring.