| Adverse event: In microbicide clinical trials, an adverse event is any unfavourable and unintended sign (for example, an abnormal laboratory finding), symptom or disease temporally associated with the use of a microbicide, whether or not considered related to the use of the microbicide being tested. |
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| Control group: The control group is a subset of the clinical trial population. Generally, individuals in the control group are given a placebo instead of the microbicide or other intervention being studied. At the end of a microbicide trial, researchers compare the rate of HIV infection among people in the “intervention group” (those who used the candidate microbicide) and the control group. If there is a statistically significant difference in the number of infections in the intervention and control groups, with fewer infections in the group using the microbicide, this indicates the microbicide likely provided some level of protection against infection. |
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| Efficacy: Efficacy refers to the capacity of a product to achieve a desired effect. In the case of microbicide clinical trials, efficacy refers to the ability of the product to protect someone from infection with HIV and, perhaps, other pathogens. (See below for more information on the phases of clinical research.) |
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| Early- and Next-generation microbicides: Early-generation microbicides were developed in the 1990s and include products that form physical barriers to HIV or change the chemistry of the vagina with the goal of making HIV less likely to infect someone. Next-generation microbicides are products that are specifically active against HIV, including microbicides that use antiretroviral drugs. IPM is focusing its product development efforts on this next-generation of microbicide candidates. |
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| Incidence: Incidence refers to the number or rate of new infections in a given period. For example, an annual HIV incidence rate of two percent means that two percent of the population was newly infected with HIV in a given year. |
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| Mechanism of action: Mechanism of action refers to the way in which a microbicide or other product protects against infection. Several different mechanisms of action are being studied in different microbicide candidates. A microbicide might work by killing or otherwise immobilising HIV; it may form a barrier between the virus and the vaginal tissue; it could boost the natural defences of the vagina against HIV; or it could prevent the virus from replicating once it enters cells. |
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| Microbicides: Microbicides are vaginal products being developed to reduce the transmission of HIV during sexual intercourse. Microbicides could take the form of a gel, cream, film, suppository or sponge, or be contained in a vaginal ring that releases the active ingredient gradually. A microbicide could also be in a new formulation and use a delivery method yet to be invented. |
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| Pharmacokinetics (PK): Pharmacokinetics refers to the study of the action of drugs in the human body, in particular the time required for absorption of the drug, its duration of action, its distribution in the body and how it is excreted. PK studies help researchers determine appropriate usage and dosage of drugs. |
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Phases of clinical research: There are three standard “phases” of human clinical trials that preventives undergo: safety, expanded safety and efficacy.
- Safety studies: These studies enrol a small group of people to evaluate a product’s safety, determine a safe dosage range, identify side effects and measure the acceptability of the product to trial volunteers. Safety studies are also known as “Phase I” studies.
- Expanded safety studies: The product being evaluated is tested in a larger group of people for a longer duration to further evaluate its safety, appropriate dosage range and acceptability. These studies are also referred to as “Phase I/II” or “Phase II” trials.
- Efficacy studies: These studies evaluate a product’s efficacy. In the case of microbicides, efficacy studies test a product’s ability to protect people from infection with HIV and, perhaps, other pathogens. Large numbers of people are usually enrolled in efficacy trials of HIV prevention interventions. Thousands of women will participate in some microbicide efficacy trials. These trials are also referred to as “Phase III” trials.
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| Placebo: A placebo is an inactive gel or pill that has no preventive or therapeutic value and which has been established to be safe for use. In most clinical studies, participants in the control group receive a placebo instead of the product being evaluated. This allows researchers to compare the effects of the intervention under study against the placebo. |
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| Prevalence: Prevalence refers to the total number or rate of infection currently in a population. For example, an HIV prevalence rate of 15 percent means that 15 percent of the population is living with HIV infection at the present time. |
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| Primary endpoint: The primary endpoint is the overall outcome that the clinical trial protocol is designed to evaluate. |
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| Protocol: All clinical trials are based on a protocol or study plan. The protocol details how a study will be organised and implemented so that it answers specific research questions and safeguards the health of trial volunteers. The protocol describes what types of people may participate in the trial, the schedule of tests, procedures, medications and dosages, and the length of the study. |
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| Randomised double-blind control trials: Enrolees in efficacy studies are usually randomly assigned to either an intervention group (which receives the candidate microbicide) or a control group (which receives a non-active, no-drug placebo). These trials are called “double-blind” because neither the trial participant nor the on-site research staff know whether the trial volunteer has received the candidate microbicide or the placebo. |
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| Seroconverter protocol: The seroconverter protocol is the research team’s plan of action in the event a trial enrolee becomes infected with HIV during a trial. The seroconverter protocol is part of the official study protocol and may call for regular HIVrelated care and treatment for the enrolee as well as referral of the enrolee to a sub-study that includes only HIV-positive individuals. |
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| Tolerance studies: Male tolerance studies are designed to examine the effects of microbicides on male sexual partners. These studies seek to identify both the possible physiological impact of the microbicide on men, as well as men’s attitudes towards use of the product by their female sexual partners. |
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