A new study has suggested that a change in the formulation of tenofovir gel, an anti-HIV gel developed for vaginal use, may make it safer for rectal use as well.
Researchers from the Microbicide Trials Network (MTN) found that the 'new' gel was less harmful to the lining of the rectum than the original vaginal formulation, and just as effective in protecting cells against HIV.
The find has important implications for the development of a rectal microbicide that could help protect against HIV or other sexually transmitted infections during anal sex.
The original gel may not be safe or effective to use rectally because the rectal epithelium - the lining of the rectum that serves as the first line of defense against HIV - is much thinner than the vaginal lining.
To make tenofovir gel safe and more amenable to rectal use, researchers from CONRAD, a research organization, reformulated it with a reduced amount of glycerin, a common additive found in many gel-like products.
Studies found that the reformulated gel was three times less likely to cause cells in rectal tissue to release water, and equally effective against HIV as the vaginal formulation.
"The lining of the rectum is much more fragile than the vaginal epithelium, so we can't be certain a product like tenofovir gel that is safe for vaginal use will be completely safe to use in the rectum," said Charlene Dezzutti, at the University of Pittsburgh School of Medicine.
"These results provide an important bridge to clinical studies, and we have already begun testing it with men and women."
However, men and women in the study did not particularly like it and some experienced uncomfortable gastrointestinal side effects.
Researchers are hopeful the reformulated gel now being tested in MTN-007 will address these concerns.
The results will be presented at the 18th Conference on Retroviruses and Opportunistic Infections (CROI). (ANI)