Microbicides

What are Microbicides?  

The term “microbicide” refers to a range of experimental products such as gels, creams, rings, and films that aim to prevent the sexual transmission of HIV. 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 microbicide before, and sometimes after, 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 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 mucosal surfaces.

Microbicide Investment 

In 2010, total global investment in microbicide R&D was US$247 million, a 5% increase over 2009. Public-sector funders provided US$230 million (93%), the philanthropic sector US$16 million (6%) and the commercial sector US$1 million (<1%).  Of the public sector funders, the US continued to maintain the largest presence, providing US$182 million (74%) of total investment, an increase of US$9 million over 2009.  European national governments and the European Commission together accounted for US$40 million, an decrease of 9% from 2009. The commercial sector contributes to the development of microbicide 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.

Microbicide Expenditures

A subset of investments in microbicide R&D in 2010 was analyzed to provide a breakdown of global funding allocations by type of activity or product development stage: basic mechanisms of mucosal transmission (18%); preclinical testing (25%); formulations and modes of delivery (5%); clinical trials(38%); microbicide behavioral and social science research (2%); microbicide research infrastructure (8%); and policy and advocacy (4%).  Preclinical testing and clinical trials were the two largest categories, as they were in 2009, though preclinical work declined from 36% of investment in 2009 to 25% of investment in 2010. Increases were seen in investments in basic mechanisms, clinical research, and research infrastructure.