Patients & Families
Patients and Families
Phases of Clinical Trials

Adapted with permission from the Hamilton Regional Cancer Centre, Cancer Care Ontario.

New cancer treatments start in a lab where scientists identify and develop new medications and radiation therapies. Cancer treatments follow a long road, over many years, between the laboratory and the time they are approved for use. The only way new treatments are approved and become widely available is through the successful completion of clinical trials demonstrating that the treatments are both safe and effective.

Research in adults and children follows very specific rules. In clinical trial research it is important to treat each patient in the same way to make sure that differences are not due to things other than the treatment used in the trial.

Phase I
A Phase I (‘Phase One’) trial is the first step in cancer treatment research that includes patients. Phase I trials study how a treatment should be given, how often, and in what dose. These studies are followed very closely, and are set up to find out the medication dose that is safest to use in the next phase of research.

Only a small number of patients are needed for a Phase I trial. Phase I trials are only occasionally available in Nova Scotia. These trials usually need full-time investigators, research teams, and hospital facilities which are beginning to be developed in this province.

Phase II
A Phase II (‘Phase Two’) clinical trial studies the effects of a treatment for a specific type of cancer. It also studies side effects and the risks for people with your type of cancer. These studies are well controlled, closely monitored and carried out with a relatively small number of patients. In general, Phase II trials do not compare the new treatment to the standard recommended options for your type of cancer.  They give early information about how well the treatment works for a particular type of cancer and may be available at a number of centers throughout Canada and internationally. Phase II trials may be available at the Capital Health Cancer Care Program and the IWK Health Centre in Halifax and at the Cape Breton Cancer Centre in Sydney.


Phase III
Phase III (‘Phase Three’) trials are large trials that compare the new treatment with the standard recommended options being used to treat a certain type of cancer. They take place after Phase II results suggest that the new treatment or combination of treatments works. This phase gathers more information about the effectiveness and safety of the new treatment. Phase III trials can involve hundreds or even thousands of patients, and usually are available at many centres within Canada and around the world.

Most Phase III trials are randomized. Randomization means patients are placed by chance into either the group getting the new treatment or to the group getting the standard recommended options for that type of cancer. Once you agree to take part in a Phase III trial, the actual treatment for you will be chosen by chance (like the flip of a coin) among the treatments under study.

Some Phase III trials are called ‘Placebo-Controlled’. In a placebo controlled trial, half the patients receive the treatment that is being studied and the other half receives an identical but inactive treatment (i.e. a sugar pill that looks the same as the treatment pill). In most cases, the medicine under study is an add-on to other medicines typically recommended for a type of cancer and the question is whether or not the ‘add-on’ medicine adds benefit to the standard treatment. In these trials, ALL patients receive the standard treatment in addition to either the active medicine or placebo. In these trials, neither the patient nor their health care team knows if they are receiving the study medicine or the placebo, in addition to the other treatments, in order to reduce the chance of bias in assessing the efficacy or safety of the treatment. This information however, is readily available if there is a need to find out which treatment is being received in order to treat any significant side effects.
 Phase III trials are the most common trials in Nova Scotia and may be available at the Capital Health Cancer Care Program and the IWK Health Centre in Halifax and the Cape Breton Cancer Centre in Sydney.


Phase IV
Phase IV ("Phase Four") trials are carried out after the treatment or drug has received approval for use in Canada. These studies usually involve the use of the drug under normal conditions. There are not many Phase IV trials in cancer care.

Sometimes Phase IV trials are needed to find very rare side effects of the treatment. Phase IV trials may also study how effective the treatment will be in groups of patients who may not have been studied in the Phase III trials. This might include elderly patients or patients from specific ethnic groups.


Other types of clinical trials
Supportive care, prevention and screening trials are not usually done in phases. They compare groups of people using certain plans or treatments, such as counselling, changing behaviour or new ways to find out if you have cancer. These clinical trials are very important and have led to many changes in the way that cancers are detected, followed and in how patients are supported either during their treatments or in follow-up as cancer survivors.

Ask your doctor or nurse about these and other types of trials that might be available for you to participate in, or see Nova Scotia Clinical Trials for more information.

Clinical Trials
More information on clinical trials available in Nova Scotia is available from the Canadian Cancer Trials website.