Between 2005 and 2007 , 3099 women were enrolled in HIV Prevention Trials Network ( HPTN ) protocol 035 , a phase II/IIb evaluation of the safety and effectiveness of BufferGel and PRO 2000 for prevention of STIs , including Neisseria gonorrhoeae ( NG ) , Chlamydia trachomatis ( CT ) and Trichomonas vaginalis ( TV ) .