Understanding the Phases and Types of Clinical Trials

Content authored by Jessica Severt RN, BSN, Clinical Research Nurse Coordinator at Thompson Cancer Survival Center

Clinical Trials Clinical Trials: Phases and Types

Did you know that most drugs go through at least 3 different levels of clinical trial testing before they are approved?  It may also surprise you to know, that even after a drug is approved – researchers continue to study it for years while patients are taking it as part of their standard care!

Clinical trials test new cancer treatments in a series of steps, called phases. A medication’s success in one phase determines if it will advance to testing in the next phase.

There are four different phases of clinical trials in humans. The phase regulates what types of questions researchers are trying to answer at that point in the process.  Understanding more about the series of trials a new drug goes through to determine the dosage, safety, side effects, and treatment benefits empowers patients in their cancer treatment journeys. Let’s look a bit closer at each phase.

Phases of Clinical Trials

Before any testing on a drug can be conducted on people, it goes through lab studies or pre-clinical research. If researchers find promising results in cell or animal studies, a drug can move forward for more research. In order to conduct any trials using humans, the FDA must review and approve a specific IND, Investigational New Drug Application.

Some Phase 0 trials are conducted in humans, but they are not required and therefore are not widely used. These trials often have very small study populations and almost never benefit the people participating in this early phase trial. The information discovered in these brief studies, which often require additional testing such as frequent imaging or biopsies, can benefit future trial participants, accelerate later results, or speed up the path to the treatment’s final approval.

Phase 1:

This is the earliest mandatory phase of a clinical trial in humans. In Phase 1 trials, researchers determine whether a new treatment is safe and effective, establish a side effect profile, and define a dosage regimen.  It is vital for the researchers to see that this new treatment is safe for patients and successful in slowing tumor growth or achieving the treatment goal. Trials in this phase have a very small number of participating patients, usually about 20-100 participants. If all goes well in this phase, then the treatment can move on to the next phase.

*According the FDA, about 70% of drugs that begin Phase 1 trials move to the next phase.

Phase 2:

This next phase of trial usually includes several hundred patients as study participants and can last as long as 2 years. This phase is an opportunity to test the drug or treatment in a larger group of people to learn more about the side effects of the treatment and further assess its effectiveness. This phase also helps to refine the drug’s dosing levels. If the studied drug proves to be effective and has no unexpected/intolerable side effects then it will move to Phase 3.

*About 33% of drugs entering Phase 2 trials progress to the next phase.

Phase 3:

During these trials, researchers further evaluate the drug’s effectiveness, safety, and side effects. Additionally, the investigational drug is compared with whatever is the current standard of care. Phase 3 studies usually involve around 300-3,000 study participants and can last 1-4 years.

* Approximately 25-30% of drugs in Phase 3 studies will move to the next phase or approval per the FDA.

Phase 4:

Phase 4 trials are observational or registry studies. Patients will be receiving a drug that is already FDA approved as a part of their standard treatment, which is managed by their physician. They will consent to be followed by the study, involving periodic questionnaires and allowing the study team to collect health care information from medical records. This allows researchers to determine how well this newly approved treatment works over long periods of time and possibly identify side effects that were not discovered in earlier phases.

Clinical TrialsTypes of Clinical Trials

Drug Trials:

All phases of a drug trial are meant to test for the safety and tolerability of a medication. Drug trials also help researchers determine something called pharmacokineticswhich is just a big word to say how quickly a drug moves through a patient’s body and pharmacodynamicsanother big word to say “what the body does to the drug”. 

Thompson Cancer Survival Center offers appropriate patients several clinical trials for various cancer types that involve chemotherapy, immunotherapy, IV drugs, and drugs that can be taken by mouth. Learn more by visiting the Clinical Research webpage.

Device Trials

The FDA defines a Medical Device as “any healthcare product that does not achieve its principal intended purposes by chemical action or by being metabolized“.  There are several classifications of devices that progress through specific phases including pre-clinical trial investigations and a series of applications for approval to move forward with testing. Medical devices can be a simplistic as tongue depressors or as sophisticated as the robots that surgeons use to do surgeries. 

The device trials currently available to Thompson Cancer Survival Center patients are a little different than a device that may be tested for cardiac or diabetes issues. Devices commonly used in treatments for these conditions may be in trials to assess effectiveness or treatment delivery efficiencies.  Device trials currently open at Thompson are researching the device’s ability to accurately and consistently detect any breathing or heart rate issues when it is worn while the patient is at home after receiving cancer treatment here at the center. 

The More You Know:

Currently, Thompson’s Clinical Research department has clinical trials available for cancer patients that are Phase 2, 3, 4. The available trials include treatment with medication and/or radiation, as well as device trials. Our team is dedicated to offering quality clinical trial options for cancer patients in our community because this is what helps doctors find new and better ways to prevent, detect, and treat cancer. 

If you are interested in learning more about Clinical Trials, Thompson Cancer Survival Center is hosting the First Annual Clinical Trials Symposium on October 29th at the Center located on the Fort Sanders campus in Knoxville. To learn more and register to attend the conference live or virtually, click here.











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