Clinical trials and drug safety
On this page
- The issue
- About clinical trials for drugs
- Phases of clinical trials
- Possible benefits
- Possible risks
- Reduce your risk
- The role of clinical trials in drug approvals
Every year, Health Canada receives hundreds of new clinical trial applications. These applications are to test new drugs (including vaccines) or new uses of approved drugs on humans. When you participate in these trials, you have a chance to take part in research that could improve your health or the health of others.
Clinical trials can be an important treatment option. However, like all drugs, the drugs used in clinical trials have possible benefits and risks. There is often less information about the safety and efficacy of a drug being studied in a clinical trial than for an authorized drug.
In Canada, pediatric patients (children and youth) can participate in clinical trials with the patient's and their parent's permission. Health Canada takes an active role in protecting the health of Canadians who take part in clinical trials, including children and youth.
There can be big differences in how a drug works in an adult and how it works in a child or youth. That is why clinical trials with children and youth are important to learn whether a drug is safe and effective for these patients.
Before you take part in a clinical trial, you should talk about the possible risks and benefits with your health care provider, as well as your family and others in your support system. This will help you to decide whether to participate in a trial.
About clinical trials for drugs
When researchers develop new drugs, the first tests are called pre-clinical studies. These tests are done using cells, tissue samples or animals. If the pre-clinical test results are promising, the next step is a clinical trial.
Clinical trials are studies to find out whether a drug is safe and effective for people. The people who take part in trials are volunteers. They may be:
- patients with a disease
- healthy people who want to help move medical knowledge forward
The person or organization that tests a drug is called a sponsor. Health Canada does not sponsor or conduct drug research. Sponsors of clinical trials are usually:
- drug companies
- researchers from a hospital, university or research organization
Clinical trial application
Before conducting a trial, the sponsor submits a clinical trial application to Health Canada. Our scientists review the application to make sure:
- drugs are used in the right way for the patients being studied
- any risks in using the drug are lowered as much as possible
- the best interests of the people taking part in the trial have been considered
- goals of the trial can be met
- protect the health of the people in the trial
- be well designed and conducted by trained professionals
- be monitored and side effects reported
- be reviewed by a Research Ethics Board
Who else is involved
The people who carry out clinical trials are called investigators. Investigators in Canada are usually physicians. Researchers, nurses or other health professionals may also be involved in a clinical trial. Trials often have research teams and take place in hospitals, medical clinics, doctors' offices and universities.
Phases of clinical trials
Clinical trials are often done in 4 phases. Each phase has a different purpose and helps researchers answer specific questions. Some trials combine phases.
- Phase 1: These trials test an experimental drug on a small group of people for the first time. The purpose is to:
- look at the drug's safety
- find out the safe dosage range
- see if there are any side effects
- Phase 2: The drug is given to a larger group of people (usually 100 or more) to:
- gather data on how well the drug works to treat a disease or condition
- check the drug's safety on a wider range of people
- figure out the best dose
- Phase 3: The drug is given to even larger groups of people (usually 1,000 or more) to:
- make sure it is still effective
- monitor side effects
- compare it to commonly used treatments
- collect information about the drug that will allow it to be used safely on the market
- Phase 4: These trials take place after the drug is approved and is on the market. Information is gathered on things like the best way to use a drug and the long-term benefits and risks.
When you take part in a clinical trial, you help others by moving medical research forward. Also, if you have a disease, there could be personal benefits, such as:
- you may get early access to a new treatment with positive results
- the treatment may cure or control your condition or improve your quality of life
- you may get more expert health care from the research teams that are involved in the study
If your reason for being in a clinical trial is to get a new treatment, be aware that this may not happen. Clinical trials often compare a new drug to:
- an approved drug that is already on the market
- a placebo (a dummy treatment with no active ingredients)
In many cases, people are not told which treatment they are getting. This is done to make sure the results are not biased. Even if you get the new drug, it may not help you. It might be less helpful than a treatment you were using before the trial. There is also a risk of serious short- or long-term side effects as the safety of an investigational drug is not as clear as an approved drug.
A clinical trial involves travel, tests and possible hospital stays, which can take up a lot of your time.
Reduce your risk
If you participate in a clinical trial, you should understand what is involved and give your consent before starting the trial.
Read the informed consent form before you decide. By understanding the benefits and the risks, you can make an informed choice about participating. It's also a good idea to talk to your family and friends. If you have questions, talk to your health care provider.
If you choose to join a clinical trial:
- Take medicines exactly as you are told. Follow all of the directions given by the clinical trial doctors and staff.
- Go to all of your scheduled visits.
- Contact the clinical trial doctors and staff if you have any side effects, even if you're not sure whether the trial is the cause.
You have the right to quit a clinical trial at any time. If you quit, the trial's medical staff will make sure that you are taken off the medication safely.
The role of clinical trials in drug approvals
The pre-market stage consists of:
- pre-clinical studies
- clinical trials
- regulatory product submission
- submission review
- market authorization decision
If clinical trials prove the drug's benefits are greater than its risks, the drug company will apply to Health Canada for market approval to market that drug. This application includes detailed information about the drug's safety, efficacy and quality. This information includes:
- the results of pre-clinical studies and clinical trials
- details about how the drug is made, packaged and labelled
- health claims and information about any side effects
Health Canada's scientists review this information. The drug is approved for sale in Canada if:
- the benefits are greater than the risks
- the risks can be lowered
Once approved, the new drug gets:
The post-market stage involves the surveillance, inspection and investigation of a drug while it is on the market.
Ensuring safe and effective drugs
Health Canada plays an active role in making sure Canadians can get safe and effective drugs. As part of this work, we protect the health of Canadians who take part in clinical trials. We:
- review clinical trial applications
- make sure that drug companies lower the risk of side effects by doing all of the safety tests
- keep track of negative side effects that can happen in clinical trials and take action when needed
In some cases, inspectors visit sites where clinical trials take place to:
- make sure that doctors are monitoring the patients
- make sure that trials are running the way they should
If there are severe side effects, we make sure that patients are checked more closely or we may stop the trial.
Health Canada also gives Canadians information about clinical trials so that they can make choices based on what they have learned.
The clinical trials database lists all of the phase 1, 2 and 3 clinical trials involving patients in Canada. It has information on the:
- sponsor and title of the study
- drug being tested
- start and end dates
- type of volunteers needed (for example, age range, sex, medical condition)
The Canadian Institutes of Health Research funds health research, including clinical trials.
- Clinical information on drugs and health products
- Clinical trials - guidance documents
- Clinical trials manual
- Clinical trials database
- COVID-19 drugs and vaccines
- Regulating vaccines for human use in Canada
- Clinical trials outside of Canada (search for Canadian trials)
- Controlled trials outside of Canada (search for Canadian trials)
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