A summary of preclinical topical microbicide rectal safety and efficacy evaluations in a pigtailed macaque model.
BACKGROUND
There is widespread recognition of the potential promise of vaginal microbicides as a tool to combat global human immunodeficiency virus/acquired immunodeficiency syndrome and sexually transmitted infections epidemics, and candidate product development has maintained a rapid pace in recent years; however, rectal microbicide development has received less attention. As it is likely that commercial products developed for vaginal use will also be used rectally, there is a clear need to assess the safety and efficacy of candidate microbicide products specifically in the rectal compartment.


METHODS
We have developed a standardized protocol for preclinical rectal safety and (chlamydial) efficacy assessment of topical microbicide candidates in a nonhuman primate model. We evaluated a total of 12 test compounds for rectal safety (via rectal pH, microflora, and rectal lavage) and 1 compound for efficacy against rectal chlamydial infection.


RESULTS
In this article, we describe our methods in detail and summarize our results, particularly noting the ability of our model to distinguish products with deleterious effects on the rectal environment. We also outline the specific criteria used to recommend products move into preclinical rectal efficacy trials or be recommended for reformulation to the product developer. In summary, we observed significant adverse effects in 2 products. The single product that underwent efficacy evaluation was not observed to be protective against rectal chlamydial infection.


CONCLUSIONS
A preclinical safety and efficacy model is critical to promoting rectal microbicide development, which will ultimately offer a significant opportunity for intervention in the global HIV/AIDS epidemic.
Patton
Dorothy L
DL
Department of Obstetrics and Gynecology, Box 356460, University of Washington, Seattle, WA 98195-6460, USA. dpatton@u.washington.edu
Sweeney
Yvonne T Cosgrove
YT
Paul
Kathleen J
KJ
D000285:Administration, Rectal; D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage* / Q000009:adverse effects; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage* / Q000009:adverse effects; D002690:Chlamydia Infections / Q000517:prevention & control* / Q000635:transmission; D002692:Chlamydia trachomatis; D004353:Drug Evaluation, Preclinical; D005260:Female; D015658:HIV Infections / Q000517:prevention & control; D008254:Macaca nemestrina; D008297:Male; D012007:Rectum / Q000187:drug effects
D000890:Anti-Infective Agents; D000891:Anti-Infective Agents, Local