Definition

A study that tests the safety, side effects, and best dose of a new treatment. Phase 1/phase 2 clinical trials also test how well a certain type of cancer or other disease responds to a new treatment. In the phase 2 part of the clinical trial, patients usually receive the highest dose of treatment that did not cause harmful side effects in the phase 1 part of the clinical trial. Combining phases 1 and 2 may allow research questions to be answered more quickly or with fewer patients. Also called phase I/II clinical trial.