About Clinical Trials

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What is a Clinical Trial?

In its most basic form, a clinical trial is a research study that involves people with the purpose of testing a new drug, intervention (i.e., a new type of surgery), diagnostic test, medical device, or other health-related tools to understand whether they provide benefit to a patient. A clinical trial is one of the very last stages in a long journey of discovery that involves an idea, a hypothesis, a plan of action, the development of a team, sourcing funding, laboratory experimentation, running statistical analyses, writing reports, getting consortium approval, ethics clearance and many other steps. For health research, the ultimate goal is to prove that a medical approach is more effective, less costly, less concerning, and/or less invasive for a patient.


What are the different types of clinical trials?

There are many different types of clinical trials. Two of the most common are:

  1. Therapeutic Clinical Trials trials focus on testing a particular drug, therapeutic agent (i.e., immunotherapy), surgical technique, or other therapy-related treatment to understand its impact on an illness or disease. Pediatric cancer clinical trials may also involve the advancement and intensification of therapy for pediatric cancer types that carry a poor prognosis.

  1. Non-therapeutic clinical trials focus on advancing the understanding of the biology of an illness and its effect on the patient. Non-Therapeutic Clinical Trials may involve the collection and analysis of blood, tumour (at initial diagnosis, relapse, and other stages of the disease), bone marrow, and other such specimens to understand the biology and fundamental characteristics of the disease. Non-Therapeutic Trials may concern the ongoing monitoring of patients after the completion of cancer treatment to understand the long-term effects on the cancer survivor, may track the lifestyle choices of cancer survivors, the impact of cancer treatment on the entire family, etc.

Three Phases of Clinical Trials

Phase 1: Dosing and Side-Effects

If a particular drug shows promise in the laboratory, a Phase 1 clinical trial can be the next step. Phase 1 trials are typically small in size and when they are testing an drug or intervention, the clinical trial focus on issues of finding the right dose, side-effects, and overall patient safety. In a therapeutic trial that examines a possible treatment, the goal is to determine the appropriate therapeutic dose of the drug and the maximal dose that can be given without the patient experiencing serious side-effects.

Phase 2: Response

If a Phase 1 trial has been deemed to be successful and the necessary resources are available, the intervention that was tested may move to a Phase 2 clinical trial. In a therapeutic Phase 2 clinical trial, the focus is on the effect of the drug(s) on a particular type of illness, or group of associated illnesses (e.g., cancer), while continuing to keep a close eye on any side-effects.

Phase 3: Improved Survival

If a Phase 2 trial is determined to be successful and the necessary resources are in place, a Phase 3 trial may be done. Phase 3 trials are much larger in size (from hundreds to thousands of people) and are very expensive, taking many years to complete. A Phase 3 trial randomizes patients into different treatment arms of the study so that the current standard of care (control arm of the trial) can be compared against the new treatment option (the experimental or investigational arm of the trial).

Randomized Clinical Trials

Randomization is typically used in Phase 3 clinical trials. Randomized trials are a way to remove bias in the experimentation process by randomly assigning participants into the control arm or the investigational/experimental arm(s) of the clinical trial. The process of assigning participants to an arm of the clinical trial may be done randomly (e.g., assigned by a computer program) or may be done deliberately based on a certain characteristics of the illness (e.g., specific genomic characteristics of the cancer).

Find a Clinical trial

For a list of current clinical trials, visit these websites:

Information About Clinical Trials for Kids

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