Phases of Clinical Trials

Research

Phase I Trial: A Phase I clinical trial involves the fewest number of participants and is designed to determine the safety and appropriate dosage of a drug or treatment for humans

  • Usually only 15-30 patients will enroll in a phase I trial. The physicians are looking to see how the human body handles a particular new drug and what the best way to give the drug is.

  • Phase I trials are often designed in a Dose-Escalating fashion. Usually a certain number of patients (often 3) will receive the investigational drug at a starting dose level. This dose level is often determined by pre-clinical trials conducted in the laboratory.

  • The side effects and safety of the drug at this level will be determined. If serious side effects are seen, then the dose is reduced and an additional number of patients (often 3-6) are treated.

  • If serious side effects are not seen, the dose level is increased and more patients (often 3-6) will be enrolled.

  • Dose levels will continue to be increased until it has been determined that the human body cannot withstand any higher dosing. This is called the maximum tolerated dose (MTD). The MTD will then be used to treat a larger number of patients to determine additional side effects in the next phase of clinical trials (phase II).

Participants in phase I trials can be patients who have a cancer where there is no standard of care treatment or therapy plan or those with cancer that has not previously responded to standard therapy.

  • Being one of the first people to have access to a potential new drug is a benefit from participating in a phase I trial. If the drug works, the patient’s cancer may respond.

  • Phase I trials are often the first time a drug is used in humans, side effects can be serious. As a result, not all phase I trial drugs continue to be studied.

Phase II Trial: Phase II trials are designed to test the effectiveness of a drug in a specific population of patients.

  • Phase II trials are based on the results from earlier phase I trials and involve a larger number of people (usually less than 100).

  • The treatment in phase II trials is evaluated for effectiveness against a certain type of cancer.

  • In most phase II trials, each participant gets the same dose of study drug. Additional information about the drug’s safety will be collected during the trial.

The long-term benefit of phase II trials is often difficult to predict. Phase II trials that continue to show effectiveness against a disease will often go on to phase III.

Phase III Trial: Phase III trials are much larger clinical trials (involving more than 100 people) and are designed to compare the new treatment against the standard of therapy for a particular disease.

These trials are “randomized” which means that a certain number of people who enroll on the trial will get the standard of care for their disease whereas others will get the new drug/treatment.

  • Each treatment is called an “arm”. If you participate in a randomized trial, neither you nor your physician gets to choose which treatment arm you get.

  • Randomization trials can be “open-label” or “blinded”. They can also be “placebo controlled.”

  • Open label means that you are aware of which treatment arm you are getting. You will know if you are being treated with standard of care therapy or if you’re getting the investigational drug/treatment.

  • Blinded means that neither you nor your physician knows which drug you’ll be getting.

  • Placebo controlled means that one arm of the study doesn’t get treatment. Patients who are randomized to the placebo arm will be given a substance that looks exactly the same as the study treatment but will have no effect on the disease. Placebo controlled trials are often used when there is no standard of care treatment.

  • The results of a phase III trial should tell us whether the new treatment is better, worse or the same as the current standard of care treatment.

Participating in a Phase III trial will allow you to receive nothing less than the standard of care therapy.

  • If you chose not to participate in the trial, you would receive standard of care therapy.

  • If you chose to participate in the trial, you have a chance of receiving standard of care therapy.

  • You will also have an opportunity to receive the new therapy.

  • The risk of participating in the trial would be that the new therapy is not as effective against your disease as standard of care might be.

  • Since there are a larger number of people participating in phase III trials, additional side effects may be discovered.

Phase IV Trial: A phase IV trial is designed to further evaluate the long term safety of a particular treatment. Phase IV trials are sometimes called “Post-marketing” studies as they are often conducted after FDA approval and after the drug is “on the market.”

Types of clinical trials:

Phase I Trial: Involves the fewest number of participants and is designed to determine the safety and appropriate dosage of a drug or treatment for humans.
Phase II Trial: Is designed to test the effectiveness of a drug in a specific population of patients.
Phase III Trial: Is a larger clinical trial (involving more than 100 people) and is designed to compare the new treatment against the standard of therapy for a particular disease.
Phase IV Trial: Is designed to further evaluate the long term safety of a particular treatment.