In an unprecedented move, US drugmakers Merck & Co and Bristol-Myers Squibb have signed separate licensing deals with the International Partnership for Microbicides for the use of their antiretroviral drugs in the development of an experimental microbicide for the protection of women from HIV.

Importantly, the drugmakers have each agreed to licence their drugs without royalties; Merck’s CMPD 167 and Bristol-Myers Squibb’s BMS-378806 will be used in the development of an effective microbicide which, in a gel or cream format, should provide an easy-to-use method for women to protect themselves against infection with the virus.

This marks the first time a pharmaceutical company has granted a license for an anti-HIV compound for development as a microbicide when the class of drugs, in this case entry inhibitors, is so early in development, the firms noted.

A study published in this week's Nature will report that, when used as vaginal microbicides, CMPD 167 and BMS-378806 protected some macaque monkeys from infection with a virus similar to HIV. These findings are highly significant considering current estimates that even a partially effective microbicide could prevent 2.5 million HIV infections over a period of three years, according to the companies. Therefore, extensive use of an effective microbicide could substantially hold back spread of the disease, particularly in sub-Saharan Africa, which accounts for around 60% of new HIV infections, while a vaccine is being developed.

Commenting on the deals, Dr Helene Gayle of the Bill & Melinda Gates Foundation, which is a major supporter of IPM, stated: "These innovative agreements demonstrate how the public and private sectors can work together to move exciting new technologies forward to protect women from acquiring HIV. Bristol-Myers Squibb, Merck and J&J are leading by example in entering into partnerships to develop their most promising compounds as potential new HIV prevention technologies.”