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.