Targeted cancer therapies are drugs designed to interfere with specific molecules necessary for tumor growth and progression. Traditional cytotoxic chemotherapies usually kill rapidly dividing cells in the body by interfering with cell division. A primary goal of targeted therapies is to fight cancer cells with more precision and potentially fewer side effects
Therapeutic monoclonal antibodies target specific antigens found on the cell surface, such as transmembrane receptors or extracellular growth factors. In some cases, monoclonal antibodies are conjugated to radio-isotopes or toxins to allow specific delivery of these cytotoxic agents to the intended cancer cell target. Some examples are bevacizumab, humanized monoclonal antibody targeting VEGF-A; cetuximab, chimeric monoclonal antibody targeting EGFR; and ipilimumab, fully human antibody with an immune system target CTLA-4.
Small molecules can penetrate the cell membrane to interact with targets inside a cell. Small molecules are usually designed to interfere with the enzymatic activity of the target protein. Some examples are bortezomib, a small molecule proteasome inhibitor; imatinib, a small molecule tyrosine kinase inhibitor, and seliciclib, small molecule cyclin-dependent kinase inhibitor.
The FDA has approved multiple targeted drug cancer therapies, and many more are being studied in clinical trials either alone or in combination with other treatments.