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About Clinical Trials

What is Involved in a Clinical Trial?

Clinical trials are research studies that involve drugs and people; therefore, strict review processes are in place to ensure the safety of participants. Phase I, II and III clinical trials are reviewed and monitored by: 1) Health Canada; 2) Ethics committees at each of the participating hospitals or clinics; and sometimes also by the 3) “Data Safety Monitoring Board”, an independent group of experts.

Only the studies that pass these rigorous approval processes are allowed to recruit and enroll patients. There are four phases or types of clinical trials, and each phase is designed to answer specific questions.

Generally speaking, Phase II and Phase III clinical trials compare a new treatment that is not yet approved by Health Canada or not yet funded by any province, a new combination of treatments, or a new dosing schedule, to the current “standard of care” (best available existing treatment). In these cases, the randomized controlled trial will involve two or more “arms”: a control arm and an experimental arm.

Phase I: What is the best and safest way to administer the new therapy?

Phase I trials usually involve a small number of volunteers. The testing establishes the optimal dose for the new agent, and perhaps the best way to administer it (eg, orally or intravenously).

Phase II: Does the new agent work in a selected group of patients? 

Phase II trials typically involve larger groups of volunteers compared to Phase I trials. Volunteers are usually chosen to reflect a particular type or stage of the disease being treated. The goal is to evaluate how effective the new therapy is in treating the disease in this type of patient. All of the possible side effects are also monitored.

Phase III: Is the new agent effective, particularly in comparison to the best available existing treatment?

Only therapies that are effective, safe and have tolerable side effects can proceed to Phase III testing. Phase III trials compare the "standard of care" to the new treatment and they are usually the largest, involving hundreds or even thousands of patients at cancer centres around the world.

Patients are usually assigned randomly to either the new therapy (often referred to as the treatment group) or the existing therapy (control group). If there is no existing therapy, the new agent may be compared to a placebo (“sugar pill”) but this is seldom necessary in myeloma research.

In order to ensure that expectations don’t affect the assignment of people into groups or the interpretation of the data, Phase III trials are often “blinded” to eliminate bias. “Blinded” means the patients do not know which agent they are getting. “Double blinding” is often used so that neither the patient nor the researcher knows who is getting the new agent until the study is completed.

Phase IV: Does the new agent work well in the “real world”?

Phase IV trials are sometimes referred to as "post marketing research". It is research on a drug that has already been approved and is being used widely. These trials may be conducted to determine how the drug works without the controlled conditions of a Phase III trial to see if there are any significant long-term effects of the therapy or whether the drug could be used for other indications. Phase IV trials do not need to be reviewed by Health Canada.

Summary of Clinical Trial Phases

Phase Number of Participants Goals


15-30 patients
  • To find a safe dosage
  • To decide how the agent should be given
  • To observe how the agent affects the human body


Under 100 patients
  • To determine if the agent or intervention has an effect on a particular cancer
  • To see how the agent or intervention affects the human body
III Generally, from 100 to thousands of people

To compare the new agent or intervention (or new use of a treatment) with the current standard

IV Generally, from 100 to thousands of people

To further evaluate the long-term safety and effectiveness of a new treatment