What is Targeted therapy?

Targeted therapy

Targeted therapy is a type ofCancer Treatmentthat uses drugs designed to target cancer cells without affecting normal cells.

Cancer cells typically have changes in their genes that make them different from normal cells. Genes are part of a cells DNA that tell the cell to do certain things. When a cell has certain gene changes, it does not behave like a normal cell. For example, gene changes in cancer cells might allow the cell to grow and divide very quickly. These types of changes are what make it a cancer cell.

But there are many different types of cancer, and not all cancer cells are the same. For example,Colon CancerandBreast Cancercells have different gene changes that help them grow and/or spread. Even among different people with the same general type of cancer (such as colon cancer), the cancer cells can have different gene changes, making one persons specific type ofColon Cancerdifferent from another persons.

Researchers have also learned that the environment in which different cancers start, grow, and thrive are not always the same. For example, some cancers have certain types of proteins or enzymes send certain messages to tell the cancer cell to grow and copy itself.

Knowing these details has led to the development of drugs that can target these proteins or enzymes and block the messages being sent. Targeted drugs can block or turn off signals that make cancer cells grow, or can signal the cancer cells to destroy themselves.

Targeted therapy is an important type of cancer treatment, and researchers will develop more targeted drugs as they learn more about specific changes in cancer cells. But so far, only a few type of cancers are routinely treated using only these drugs. Most people getting Targeted therapy also need surgery, chemotherapy, radiation therapy, or Hormone therapy.

Targeted therapies are made to find and attack specific areas or substances in cancer cells, or can detect and block certain kinds of messages sent inside a cancer cell that tell it to grow. Some of the substances in cancer cells that become the targets of targeted therapies are:

• Too much of a certain protein on a cancer cell
• A protein on a cancer cell that is not on normal cells
• A protein that is mutated (changed) in some way on a cancer cell
• Gene (DNA) changes that are not in a normal cell.

The action of targeted drugs can work to:

• Block or turn off chemical signalsthat tell the cancer cell to grow and divide
• Change proteinswithin the cancer cells so the cells die
• Stop making new blood vesselsto feed the cancer cells
• Trigger your immune systemto kill the cancer cells
• Carry toxins to the cancer cellsto kill them, but not normal cells

The action of the drugs can affect where these drugs work and what side effects they cause.

Many kinds of cancer can be treated with targeted therapies, and there are many different types of targeted therapies. Here are some types with a few examples of how they are used.

• Angiogenesis inhibitors:These block the formation of new blood vessels that feed and nourish the cancer cells. Example: bevacizumab (many different cancers).
• Monoclonal antibodies:These might deliver molecules by themselves or molecules with drugs into or onto the cancer cell to kill it. Examples: alemtuzumab (certain chronic leukemias), trastuzumab (certain breast cancers), cetuximab (certain colorectal, lung, head and neck cancers). NOTE: Some monoclonal antibodies are referred to asTargeted therapybecause they have a specific target on a cancer cell that they aim to find, attach to, and attack. But other monoclonal antibodies act likeImmunotherapybecause they make the immune system respond better to allow the body to find and attack cancer cells more effectively.
• Proteasome inhibitors:These disrupt normal cell functions so the cancer cells die. Example: bortezomib (multiple myeloma)
• Signal transduction inhibitors:These disrupt cell signals so that they change the actions of the cancer cell. Example: imatinib (certain chronic leukemias)

Benefits of Targeted Therapy

Different targeted therapies offer different benefits. Depending on your treatment goals, your drug(s) may be used to:

• Block or turn off signals that tell cancer cells to grow or multiply.
• Alter proteins within cancer cells that cause those cells to die.
• Prevent new blood vessels from forming, which cuts off blood supply to your tumor.
• Tell your immune system to attack the cancer cells.
• Deliver toxins that kill cancer cells without harming healthy cells.

What are the side effects of targeted cancer therapies?

Scientists had expected that targeted cancer therapies would be less toxic than traditionalchemotherapydrugs because cancer cells are more dependent on the targets than are normal cells. However, targeted cancer therapies can have substantialside effects.

The most common side effects seen with targeted therapies arediarrheaand liver problems, such as hepatitis and elevated liver enzymes. Other side effects seen with targeted therapies include:

• Skin problems (acneiform rash, dry skin, nail changes, hair depigmentation)
• Problems with blood clottingand wound healing
• High blood pressure
• Gastrointestinal perforation (a rare side effect of some targeted therapies)

Certain side effects of some targeted therapies have been linked to better patientoutcomes. For example, patients who develop acneiform rash (skin eruptions that resembleacne) while being treated with thesignal transduction inhibitorserlotinib(Tarceva) orgefitinib(Iressa), both of which target theepidermal growth factor receptor, have tended to respond better to these drugs than patients who do not develop the rash. Similarly, patients who develop high blood pressure while being treated with theangiogenesis inhibitorbevacizumabgenerally have had better outcomes.

The few targeted therapies that are approved for use in children can have different side effects in children than in adults, includingimmunosuppressionand impaired sperm production.