"Carrageenan" preparations (such as 0.5% PRO 2000 and 3% Carraguard vaginal microbicide gels) have failed to demonstrate efficacy in preventing HIV transmission in phase III clinical multicenter trials. PRO 2000 was demonstrated to be safe, but it did not reduce the risk of HIV infection in women (as explained in the MDP 301 trial results, released in December 2009). Similarly, the phase III efficacy trial of Carraguard showed that the drug was safe for use but ineffective in preventing HIV transmission in women.