Family Health International (FHI) announced that it has halted a Phase III clinical trial of cellulose sulfate ? a potential microbicide being tested for HIV prevention in women ? in Nigeria.
Simultaneously, CONRAD, a health research organization based in Arlington, Virginia, has announced it is halting its Phase III clinical trial of cellulose sulfate at sites in Benin, India, South Africa, and Uganda.
Cellulose sulfate (CS) was one of four microbicide candidates in Phase III effectiveness trials for prevention of HIV and other sexually transmitted infections. A review of the preliminary results of CONRAD’s cellulose sulfate trial by an Independent Data Monitoring Committee (IDMC) for CONRAD’s study determined that cellulose sulfate use could lead to an increased risk of HIV infection.
Separately, Family Health International decided to close its cellulose sulfate study in Nigeria after the Data Monitoring Committee (DMC) for the FHI study ? an independent advisory group of experts ? reviewed the interim results from CONRAD’s cellulose sulfate study. FHI’s DMC also reviewed interim data from FHI’s Nigeria study and found no evidence of increased risk of HIV infection.
“In Nigeria, we did not find any evidence of greater risk of HIV infection,” said Dr. Vera Halpern, principal investigator of FHI’s trial. “But we also found no evidence that the product was effective in preventing HIV. Given the disappointing results from CONRAD’s study of the same microbicide candidate in other countries, the responsible course of action was to halt our study.”
Cellulose sulfate was assessed in multiple safety trials before entering Phase III HIV prevention trials. The gel, also known as Ushercell, is a cotton-based compound developed by Polydex Pharmaceuticals, based in Toronto, Canada. Prior to the Phase III HIV prevention trials implemented by Family Health International and CONRAD, cellulose sulfate had been evaluated in 11 rigorous clinical safety and contraceptive trials involving more than 500 participants. Eight of those trials were conducted in the United States. Evidence from those early animal and human studies indicated that cellulose sulfate had a strong safety profile with minimum vaginal irritation; in laboratory studies, cellulose sulfate exhibited antimicrobial activity against several sexually transmitted infections, including HIV.