What is a Microbicide for HIV Prevention? The term “microbicide” refers to a range of experimental products such as gels, creams, suppositories and films that aim to prevent the sexual transmission of HIV. Some microbicides aim to prevent infection with other sexually transmitted infections (STIs), too. Current microbicide trials are evaluating candidates that are applied vaginally or rectally using an applicator. In most of these studies volunteers are asked to use the candidate before every sex act. There is also work underway to explore other types of “delivery” systems, such as a vaginal ring that would release the microbicide that could be worn for long periods of time and wouldn’t require application just before sex. An effective microbicide would reduce the risk of HIV infection at the site of sexual exposure. There is a range of ways that a microbicide might provide this protection. It might contain an active ingredient that blocks HIV activity directly; it might provide a more general enhancement of naturally-occurring mucosal defenses and/or physical barrier at the the mucosal surfaces.
Microbicide Investment In 2008, total global investment in microbicide R&D was US$244 million, an 8% increase over 2007. Public-sector funders provided US$207 million (85%), the philanthropic sector US$35 million (14%) and the commercial sector US$2.5 million (1%). In 2008, public-sector investment in microbicide R&D accounted for 85% of the combined global funding for microbicide research, development and advocacy. The US continues to maintain the largest presence, providing US$155 million (63%) of total investment, an increase of 11% over 2007. European national governments and the European Commission together accounted for US$40 million, a decrease of 33% from 2007. The commercial sector contributes to the development of HIV prevention research in a number of ways through pharmaceutical company support. A number of companies have provided ARV compounds for development as potential microbicides along with technical support to product developers. In 2008, Pfizer and Merck provided maraviroc and L’644, respectively, to the International Partnership for Microbicides through non-exclusive royalty-free licenses. Both compounds, currently under development by IPM expand the microbicide pipeline in significant ways. Other pharma companies that have provided ARV compounds for microbicide development include Tibotec, Bristol-Myers Squibb and Gilead Sciences Inc.
Microbicide Expendtures. A subset of investments in microbicide R&D was analyzed to provide a breakdown of global funding allocations by type of activity or product development stage: 5% was devoted to basic mechanisms of mucosal transmission, 33% to pre-clinical research, 9% to product formulation, 38% to clinical trials, 5% to social science research, 5% to infrastructure, and 5% to policy and advocacy. Basic research investment declined 35% from 2007, and pre-clinical research investment increased by 59% over the same period.
