What exactly is a clinical trial?

A step-by-step look at what goes into a clinical trial


There are many different types of clinical trials, but all follow a series of steps, known as phases. If a trial is successful in the first phase, it moves on to the next – for safety reasons, it takes three successful phases before a drug is ready to be distributed to the public. Clinical trials are usually sponsored by a pharmaceutical company, university, clinic or cancer research centre, but each trial is led by an individual doctor, known as the lead or principal investigator.

Here’s what happens during the clinical trial process


Phase I: This phase is all about determining safe dosage levels, determining how treatment should be given and noting how it affects patients. Between 15 and 30 people participate in a clinical trial’s Phase I.

Phase II: During Phase II, researchers aim to determine if the new treatment has an effect on a particular cancer and how that treatment affects patients. Less than 100 people participate in this phase.

Phase III: During Phase III, the new treatment will be compared with current standard cancer treatments. This phase can see lots of participants – between 100 and several thousand.


Once a drug is distributed to the public, researchers continue to assess the long-term safety and efficacy of a new treatment or drug. This can include several hundred to a thousand participants.

Patient Know-How

  • Before you start a trial, ask lots of questions:
    – Why is the trial being done?
    – How might this treatment be different from current standard of care?
    – What costs will my provincial health insurance cover?
    – How could the trial affect my daily life?
  • Know that if you sign up for a particular phase in a trial, you don’t have to participate in all of them.
  • Only an individual with a valid licence to practice medicine can act as a clinical trial investigator.
  • Clinical trials follow strict guidelines and are closely monitored by Health Canada, the centre where the trial takes place and an ethics board.
  • Even after you sign an informed consent form, you are free to leave a clinical trial at any time.

Number of Clinical Trials in Alberta, by Trial Type:

Co-operative (academic, government or NGO-based trials): 205

Industry (pharmaceutical based trials): 325

In-House (driven by independent researchers): 373

Placebos: Placebos are used in some clinical trials to test whether a new drug or treatment is better than no treatment at all. These placebos look just like the drug being tested but don’t contain any active ingredients, and are administered to randomly selected participants for the duration of the study.

Patients are informed if a placebo is being used in a clinical trial, but not if they have been selected to take one.

Trial Terminology:

Control group: A group of participants that is receiving the current standard of care, the tested treatment or a placebo, whose results are used as comparison against the clinical trial’s participant group.

Investigator: The person responsible for conducting the clinical trial. Often, they are responsible for managing a team of researchers that work on the trial with them.

Protocol: A document that outlines and describes the objectives, design, methodology and organization of a trial. The protocol also often gives the background and rationale for the trial.

Informed consent: The process that a participant goes through in order to confirm their willingness in participating in a clinical trial.

Standard of care: The current treatment being used to treat a disease or condition that is accepted.



If you are interested in taking part in a clinical trial, speak with your health-care team and inquire about open trials that you may be eligible for.

The Alberta Cancer Foundation has committed to investing $10 million over the next five years to bring innovative cancer treatments to Albertans faster. Your donation to the Foundation can help one of these trials get off the ground.

Visit http://albertacancer.ca/investment-priorities/clinical-trials for more information on how to donate.

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