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Types of Clinical Trials

The Siteman Cancer Center offers three types, or phases, of clinical trials. As you might expect, the phases are labeled chronologically: phase I, phase II, phase III. You do not have to participate in all three phases, just the one trial that is right for you.

Phase I: Because this is the first step for each study, a phase I clinical trial typically enrolls only 15 to 30 patients with various types of cancer. The main goals of a phase I trial are usually:

  • To find the safest dose of a new treatment
  • To decide the best way to give a new treatment
  • To make sure the new treatment is safe

Phase II: The Siteman Cancer Center has more phase II studies than any other type of trial. Only treatments proven to be safe in earlier phase I studies move on to phase II. These studies typically enroll 20 to 80 patients with a specific type of cancer. The main goal of a phase II trial is usually to see if the new treatment is effective against a specific type of cancer.

Phase III: Phase III trials are the type of studies you often hear about on TV. Only treatments shown to be both safe and effective in earlier phase I and phase II studies move on to phase III. Typically, phase III trials enroll from 100 to 1,000 patients. The main goal is usually to compare a new treatment with the current standard treatment and see which is better.