Testing & Trials
Like any health technology or drug, a microbicide has to pass through a series of rigorous tests before it can be approved and made available for widespread use. These tests start in the laboratory, where researchers determine whether a compound fights HIV and STI pathogens, first in test tubes, and then in animals. If the data from these trials show that the product is 1) effective against pathogens and 2) safe (non-irritating) in animals, then clinical (human) trials can begin.
There are several phases of clinical trials
Phase I Safety Trials determine the safety of the product when used by 20 to 50 healthy, low-risk volunteers over several weeks or months. In the case of microbicides, scientists look to see whether the product causes irritation or negatively affects the vagina or rectum's normal environment.
Phase II Expanded Safety Trials test the safety of the product in a larger number of volunteers over a longer period of time. Phase II trials generally take place among volunteers whose risk profile resembles that of the women or men who will be enrolled in large-scale effectiveness trials.
Safety must also be assessed in HIV+ individuals because some HIV+ people will want to use those products and many users will not know their HIV status when they ultimately use a microbicide. Penile safety studies are normally carried out as well to ensure that product is safe and acceptable for the user's male partner.
Phase III Effectiveness Trials enrol thousands of people in several sites, and measure whether or not the microbicide actually works to prevent HIV and STIs. Some Phase II trials of microbicides can "roll into" Phase III trials as long as the data show good results.