In Phase I cancer clinical trials, researchers test a study drug for the first time to primarily evaluate the safety of the new drug. This typically involves a small group – 15-30 people – who are monitored very carefully. A placebo is not used in this phase.
This phase may also look at:
In Phase II cancer clinical trials, special emphasis is given to determining whether the therapy is effective at treating a specific type of cancer. There is no placebo given, but participants may be divided into groups where each group gets a slightly different dose or schedule that will tell the investigators which way appears to work best with tolerable side effects.
Phase II trials usually involve more people than the Phase I trials, but less than 100 people who all meet specific requirements set by the investigators.
In Phase IV cancer clinical trials, the cancer therapy is tested after it has been approved for a specific use. They are used to collect information about a therapy’s long-term effect on the patient’s quality of life, length of life and any unexpected long-term side effects.
Phase IV trials may also be used to try new combinations of approved therapies to determine if there are better outcomes.