Piecing together the HIV prevention puzzle

May 18 2009

"It's an exciting time in HIV prevention research. We will see results from a number of critically important HIV prevention research trials this year, as well as see the start of new trials around the world that will yield important answers in the years to come," said Mitchell Warren, AVAC executive director, at the release of AVAC's 13th annual report of the field.

"But scientific, community and political leaders must act now to plan for continued research and implementation of effective strategies, or this excitement will be wasted," Warren added.

The report - Piecing Together the HIV Prevention Puzzle - looks at AIDS vaccine research, where there is an energized focus on discovery, innovation and basic science and looks at the broader HIV prevention field, particularly the implications of pre-exposure prophylaxis (PrEP) and other strategies in efficacy trials today.

This analysis of the HIV prevention field comes in a year that has already brought disappointment as well as intriguing results from various prevention studies. At the same time, even trials that failed to show overall benefit, such as the Step Study of the Merck HIV vaccine candidate, have continued to generate new, valuable information and questions that would not otherwise exist.

These trials have succeeded as a result of increasingly robust partnerships between researchers and communities grappling with HIV, including gay men around the world and heterosexual women in Africa. These partnerships, along with the persistently high rates of new infections, are a continual reminder of the global commitment to and need for continuing the search for new prevention for as long as it takes.

"We hope to have new prevention intervention pieces to add to the puzzle in the next few years," said Warren. "But as the slow implementation of male circumcision to reduce heterosexual men's risk of HIV infection reminds us, we need extensive planning and guidance to ensure research results are translated into real impact against the epidemic. We can't afford to wait for efficacy results before we begin to plan. We must anticipate and tackle the major hurdles for implementation now."

The Report identifies major issues for implementation of new prevention options, including:

• Ongoing global failures to scale up access to HIV testing and counseling services.
• Persistent inattention to the needs of gay men and other men who have sex with men around the world.
• Gaps in health care infrastructure that will complicate introduction of any new strategy.

In the Report, AVAC also underscores the importance of WHO and UNAIDS getting involved in planning for the results from PrEP trials before data are available.

"WHO and UNAIDS, along with other stakeholders, need to combine their strengths now to provide leadership and coordination so that the world is ready to work with results from the many ongoing PrEP trials," said Warren.

Positive results from current vaccine, PrEP and microbicide trials will also present challenges and opportunities for other ongoing and planned HIV prevention trials.

"There has been concern that positive results from PrEP trials would require vaccine or microbicide trials to become larger, longer and more expensive, as PrEP could become a standard of prevention in these trials," said Warren. "But we believe that success in one trial will open up possibilities and options for research that could combine AIDS vaccines and other interventions as they emerge."

To help guide efforts in new areas of research and sustain ongoing research, AVAC calls for researchers and trial sponsors to begin planning on how combination strategies can be evaluated.

As the field looks to fit the puzzle pieces together, the AVAC Report also identifies a number of big questions in AIDS vaccine research for 2009 and beyond, focusing on issues such as cell-mediated viral control, HIV genetic diversity, the role of animal models, immune activation, antibodies and adjuvants.

In its analysis of the vaccine field, AVAC also assesses the progress and future potential of the Global HIV Vaccine Enterprise and considers the impact of results from the Thai prime-boost vaccine trial that are expected in September. With over 16,400 participants, this is the largest AIDS vaccine trial ever undertaken.

"In AIDS vaccine and HIV prevention research today, we see a fertile mix of big science and individual efforts, of product-oriented work and of slow and steady basic science," Warren added. "What we need now is a quick, strategic, scientific analysis of all the efforts underway, with a goal of identifying gaps and opportunities for synergy both within the AIDS vaccine field and across the vaccine, PrEP, and microbicide fields. AVAC is excited to help move the HIV prevention field toward a collaborative agenda and to prepare now for implementing potential new prevention options."

Piecing Together the HIV Prevention Puzzle is available at www.avac.org/reports.htm.