How are Clinical Trials Conducted?

Researchers who conduct a clinical trial follow a carefully designed treatment plan called a "protocol". This spells out the rules of how the treatment is administered, how many people will take part, what tests they will receive and how often.

How is it decided which treatment a participant receives?

Generally, clinical trials compare two or more treatments. Participants are "randomized" to one treatment or another. That means that the treatment "arm" or "choice" is decided by chance, often by a computer. Equal numbers of people are randomized to each treatment arm, go through their treatment, and are followed along with everyone else on the trial, usually for several years. All symptoms, side effects, and the participant's progress are closely monitored.

Some studies are "blinded". That means that neither the doctors or nurses following the patient, or the patient themselves, knows which medication he or she is taking.

Randomized and blinded trials eliminate bias in the selection of participants (having the study's results affected by human choices or other factors not related to the treatments being tested.)

Sometimes "placebos" are used in clinical trials, when the standard treatment is to just observe, or give no further treatment. A placebo is a tablet, capsule, or injection that looks like the drug being tested, but contains no drug. Some patients will receive the new drug and others a placebo, to compare whether the new treatment works better than no treatment at all.

Some studies are "open label", meaning the patient receives the new treatment being tested, or the standard treatment, and everyone is aware of which treatment is being given.