As the name suggests, Targeted Cancer Therapies are drugs that work similarly to chemotherapy, but they differ by blocking the growth of cancer cells by interfering with specific targeted molecules needed for tumour growth, rather than interfering with rapidly dividing cancerous cells seen in chemotherapy. It is also known as biologic therapy because most agents are biopharmaceuticals. There are targeted therapies for colorectal cancer, head and neck cancer, breast cancer, multiple myeloma, lymphoma, prostate cancer, melanoma and other cancers.
Most targeted therapies are either small molecules or monoclonal antibodies. Small-molecule compounds are typically developed for targets that are located inside the cell because such agents are able to enter cells relatively easily. Monoclonal antibodies are relatively large and generally cannot enter cells, so they are used only for targets that are outside cells or on the cell surface.
There are many types of targeted therapies available. They include hormone therapies (slow or stop the growth of hormone-sensitive tumours), signal transduction inhibitors (block the activities of molecules that participate in signal transduction, the process by which a cell responds to signals from its environment), gene expression modulators (modify the function of proteins that play a role in controlling gene expression), apoptosis inducers (cause cancer cells to undergo a process of controlled cell death called apoptosis), angiogenesis inhibitors (block the growth of new blood vessels to tumours), immunotherapies (trigger the immune system to destroy cancer cells), and toxin delivery molecules (monoclonal antibodies that deliver toxic molecules).
Targeted therapies are currently the focus of much anticancer drug development and many targeted therapies have been approved by the Food and Drug administration (FDA) to treat specific types of cancer.