March 11, 2013

Microbicides, vaccines, and TB diagnostics Oh my! What’s new in HIV/AIDS research?

Public Affairs Analyst, Office of HIV/AIDS
US Agency for International Development

In this guest post, Molly Schmalzbach—public affairs analyst in the Office of HIV/AIDS at the US Agency for International Development (USAID)—discusses the agency’s support for research to develop new HIV/AIDS and tuberculosis (TB) products. This post is the first in a series highlighting USAID’s new strategy for global health research and development (R&D). It originally appeared on the IMPACT blog.

Nearly all great scientific advances can be traced back to methodical R&D. R&D is a critical step in meeting goals and achieving health results that are cost-effective, sustainable, and grounded in evidence. In December 2012, USAID released its new strategy for global health R&D. The report outlines how the agency plans to address some of the world’s most challenging health and development issues through new technologies, research, and evaluation, as well as the scale-up of interventions backed by scientific evidence. HIV/AIDS is a large component of this effort, and the agency—through the US President’s Emergency Plan for AIDS Relief (PEPFAR)—is supporting very promising HIV research in several areas, including microbicides, vaccines, and diagnostic tools to detect TB in HIV-positive patients.

Microbicides: Microbicides are substances that can be applied vaginally or rectally to reduce the risk of HIV transmission during sex. Vaginal microbicides are a particularly desirable innovation because women can use these products on their own to protect themselves from HIV infection. Given that women make up almost 60 percent of people living with HIV in sub-Saharan Africa and struggle to negotiate other HIV prevention methods—such as condoms—with their partners, USAID supports microbicide R&D as a key intervention in reaching an AIDS-free generation.

Women can use this ARV-based vaginal gel to protect themselves against HIV. Photo credit: International Partnership for Microbicides.
Women can use this ARV-based vaginal gel to protect themselves against HIV. Photo credit: International Partnership for Microbicides.

In 2010, the CAPRISA 004 clinical trial showed that a vaginal microbicide made up of 1 percent tenofovir gel (a topical form of the antiretroviral drug) protected women against HIV. Following this success, a new public-private joint venture, known as Propreven, is preparing to obtain regulatory approvals, create manufacturing capacity, and support product distribution of tenofovir gel in various African countries. Two additional studies are also underway—the FACTS 001 clinical trial, which is a follow-on to CAPRISA 004 and is currently in year two, and the CAPRISA 008, a study that is examining and addressing implementation issues for future microbicide programs. Both of these studies are supported by a US and South African partnership made up of USAID, the Bill & Melinda Gates Foundation, and the Government of South Africa.

Vaccines: While microbicides are an important method in preventing HIV when tailored to specific populations, no single approach is likely to have as dramatic an impact on the HIV pandemic as an effective vaccine. That is why USAID has supported HIV vaccine R&D through the International AIDS Vaccine Initiative (IAVI) since 2001. IAVI is a public-private product development partnership that acts as a virtual pharmaceutical company to accelerate the development and clinical testing of HIV vaccine candidates. On the vaccine design front, IAVI and its partners in the Neutralizing Antibody Consortium (NAC) have designed four new immunogens—the active ingredients of vaccines that stimulate the immune system—and are testing these structures as part of potential HIV vaccines.

Two clinical trials involving IAVI’s work are examining new HIV vaccine regimens. One trial nearing completion in East Africa is evaluating a vaccine regimen that uses a new technique called electroporation, and some exciting results are expected in the coming year. Electroporation applies a small charge to effectively distribute the contents of the vaccine in the muscle and enhance uptake of the DNA. Another trial poised to begin within the next few weeks will evaluate new viral vectors carrying HIV antigens.

TB Diagnostics: Microbicides and vaccines are critical priorities for USAID’s HIV prevention efforts; however, we must also provide care and support to people already living with HIV. Since TB is the leading cause of death among HIV-positive people, USAID supports the coordination of TB and HIV services to better care for people living with each disease. In recent years the prevention, diagnosis, and treatment of TB has become more complicated because of two factors: HIV-associated TB and multidrug-resistant (MDR) TB. HIV-associated TB often goes undetected because the most common TB diagnostic, called sputum smear microscopy, is not very effective in people infected with HIV.

The Cepheid Xpert is a rapid TB diagnostic and sensitive to HIV-associated TB. Photo credit: Cepheid.
The Cepheid Xpert is a rapid TB diagnostic and sensitive to HIV-associated TB. Photo credit: Cepheid.

Fortunately, there is a promising new diagnostic for TB, including HIV-associated TB, on the horizon! This rapid and sensitive test, called the Cepheid Xpert MTB/RIF® assay, has the potential to revolutionize the diagnosis of TB. While Xpert still faces some operational and programmatic barriers, such as high costs and the need for a sustained power supply, USAID has already begun supporting the roll-out of this new tool by helping countries obtain Xpert machines, designing associated policy guidance and strategies, and developing technical approaches to guide implementation.

R&D in these three key areas is what keeps USAID at the forefront in the fight against HIV/AIDS. As David Stanton, the director of the Office of HIV/AIDS at USAID said, “These clinical trials and new technologies have the potential to dramatically change the HIV/AIDS landscape and reverse the trajectory of the global HIV pandemic.” To learn more about USAID’s strategy for global health R&D in the coming years, be sure to check out our latest Report to Congress: Health-Related Research and Development Strategy 2011-2015.