Types of Clinical Trials

Phase I Trials

The main goals of a Phase I trial are:

  • To find how much of an experimental drug is a safe dosage; sometimes older FDA-approved drugs are given in a new way
  • To find out how a drug behaves in the human body
  • To find out the side effects of a drug

In a Phase I trial, small groups of patients are treated with the same dose of the drug. Based on how well these patients tolerate the drug, small adjustments are made in the dosage and given to the next group of patients. The dose is usually increased, but it can also be lowered. Patients on a Phase I trial will continue to receive the drug only if it is helpful.

Phase II Trials

Once it has completed a Phase I trial, a new experimental drug is then tested in a Phase II trial. 

The main goal of a Phase II trial is:

  • To test the ability of the drug to shrink the tumor or control its growth

Phase III Trials

The main goal of a Phase III trial is:

  • To compare two or more treatments (one of which is usually the standard of care treatment) to one another
  • To see if a new treatment may be better than standard treatment; Phase III trials usually enroll many more patients than a Phase I or II trial