Abemaciclib is a medication used in this trial to treat advanced or metastatic breast cancer. It works by blocking certain proteins called CDK4 and CDK6, which are involved in the growth and division of cancer cells. By inhibiting these proteins, abemaciclib can help slow down or stop the progression of cancer.

Fulvestrant is another medication used in this trial for treating advanced or metastatic breast cancer. It is a type of hormone therapy that works by blocking and degrading estrogen receptors on cancer cells. Since some breast cancers need estrogen to grow, fulvestrant can help slow down or stop the growth of these cancer cells.

Breast Neoplasm – This is a condition where abnormal cells in the breast grow uncontrollably, forming a mass or lump known as a tumor. It can start in different parts of the breast, such as the ducts or lobules. As the disease progresses, the tumor may grow larger and can potentially spread to nearby tissues or lymph nodes. The growth rate and behavior of the tumor can vary, with some being slow-growing and others more aggressive. Over time, if not managed, it may lead to changes in the shape or size of the breast and can cause symptoms like lumps, pain, or discharge.

Neoplasm Metastasis – This refers to the process by which cancer cells spread from the original tumor site to other parts of the body. It occurs when cancer cells break away from the primary tumor and travel through the bloodstream or lymphatic system. These cells can form new tumors in other organs or tissues, which are known as metastatic tumors. The progression of metastasis can vary, with some cancers spreading quickly and others more slowly. This process can lead to the involvement of multiple organs, affecting their function and potentially leading to a range of symptoms depending on the organs affected.