Indevus Pharmaceuticals, Inc has been advised by the United Kingdom's Medical Research Council (MRC) that after review of data from the phase III clinical trial of PRO 2000, the company's candidate vaginal microbicide for HIV prevention, the Independent Data Monitoring Committee (IDMC) has recommended that the low-dose arm (0.5%) continue to be tested for safety and effectiveness in the trial.

The IDMC, a group of independent experts providing oversight to the MDP 301 trial, also recommended the high-dose arm (2.0%) be closed as there is no more than a small chance of the high dose showing protection against HIV infection compared to placebo gel. The trial is sponsored by the MRC and conducted by the Microbicides Development Programme (MDP), an international partnership of researchers established to develop microbicides for the prevention of HIV transmission. The 0.5 per cent dose of PRO 2000 is also being tested for safety and effectiveness in protocol HPTN 035 sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).

"We are encouraged that the MRC has decided to continue testing the 0.5 per cent dose of PRO 2000 at this advanced stage of the MDP 301 trial," stated Glenn L. Cooper, M.D., chairman and chief executive officer of Indevus. "Additionally, the NIAID trial, which has completed enrolment, continues to test the 0.5 per cent dose of PRO 2000. We are hopeful that this dose will prove to be a safe and effective treatment for the prevention of the sexual transmission of HIV".

Dr Cooper continued, "We are grateful for the generous government support of the programme, both in terms of funding and access to scientific expertise. The development of an effective microbicide is critical to the fight against HIV".

MDP 301 is a multi-national, randomized, double-blind, placebo-controlled phase III trial designed to examine the safety and effectiveness of PRO 2000 in preventing HIV infection in women. The MDP selected two PRO 2000 strengths (0.5% and 2.0%) for testing against placebo. Participants also receive a standard HIV prevention package. The trial opened in October 2005, and is currently underway at clinical centres in South Africa, Tanzania, Uganda and Zambia. Approximately 7,730 women have been enrolled in the trial to date and enrolment is expected to be completed later this year. The IDMC will continue to monitor the trial carefully until its planned completion in late 2009.

HPTN 035 is a multi-national, randomized, placebo-controlled trial designed to examine the safety and effectiveness of PRO 2000 and another candidate vaginal microbicide (BufferGel, Reprotect, Inc.) in preventing HIV infection in women. One PRO 2000 strength, 0.5 per cent, is being tested in comparison with a placebo and no treatment. The trial involves seven clinical centres in South Africa, Malawi, Zimbabwe, Zambia, and the United States.