How is a clinical trial set up?
In clinical trials for metastatic or Stage 4 breast cancer, the treatment used in the comparator arm depends on the study design. Typically, the patients in the comparator arm are given the current standard treatment that is available for their cancer. Sometimes, patients in the comparator arm are given a placebo. Another option is called treatment of physician's choice, where a doctor may choose to give the patients in the comparator arm the treatment normally used in his or her practice.
Every clinical trial studies a treatment using certain endpoints. These are specific criteria used to measure the benefits of a treatment. Different endpoints are used for different types of diseases, but many clinical trials for metastatic breast cancer use the same ones. Depending on the goals of the trial, researchers will decide if an endpoint is a primary endpoint or a secondary endpoint. Successfully achieving the primary endpoint is ordinarily the most important factor for the FDA to determine whether or not a treatment should be approved.