Make a donation

Summary of Clinical Trial Phases

Phase Number of Participants Goals
I 15 to 30 people
  • To find the safe maximum tolerated dose (MTD)
  • To decide how the treatment should be given (eg, orally or intravenously)?
  • To observe how the treatment affects the human body
II Less than 100 people
  • Uses the maximum tolerated dose (MTD) established during Phase I
  • To determine if the treatment has an effect on a particular stage of cancer
  • To see how the treatment affects the human body
III From 100 to 1,000 people
  • To compare a new agent or intervention (or new use of a treatment) with the current standard of care
IV Several hundred to several thousand people
  • To further evaluate the long-term safety and effectiveness of a new treatment in the “real world


Questions for your Healthcare Team

  • What kinds of therapies, procedures and/or tests will I have during the trial?
  • Will they hurt, and if so, for how long?
  • Will I be able to take my regular medications while in the clinical trial?
  • How do the tests in the study compare to those I would have outside of the trial?
  • Where will I have my medical care and who will be in charge of my care?