Research in targeted therapy
Researchers are developing and studying many targeted therapy drugs that can be used alone or in combination with other cancer treatments. In targeted therapy, drugs target specific molecules (for example, proteins) on the surface of or inside cancer cells. Some of these drugs block signals to the molecules that tell cells to grow or divide. This stops the growth and spread of cancer cells. Some targeted therapy drugs are already available to treat specific cancers, but researchers are studying many new targeted therapy drugs in clinical trials.
Find out more about targeted therapy.
Targeted therapy is an important part of personalized (precision) medicine, which uses information about a person’s genes and proteins to prevent, diagnose and treat cancer.
Some key areas of research in targeted therapy are:
Finding cell changes that make good targets
To develop targeted therapy drugs, we first need to learn about the changes in cancer cells that cause cancer to grow. This means time in the lab, where researchers study cells and look for genes, proteins or molecules that will make good targets. Good targets are those that cause cancer cells to grow and live. In normal cells, genes make proteins that cells need to stay healthy. But sometimes this can go wrong. For example, some genes make too many copies of themselves or combine (fuse) with other genes so cells start to grow and divide abnormally or live longer than they should. In the lab, doctors can test cancer cells to see which genes and proteins are normal and which aren’t. With this information, researchers try to develop new drugs that target abnormal genes and proteins in cancer cells while harming normal cells as little as possible.
Once a good target is found, the challenge is to design the drug to hit or bind to these targets. In some cases, researchers have found good targets but they can’t find a place on the target where a drug can bind to. This is one of the biggest challenges in developing targeted therapy drugs.
Continuing to test new therapies
Researchers continue to test therapies that are being used to better understand how they work and to try to improve them. Some of the newer targeted therapies that researchers continue to study include:
PI3K inhibitors (phosphoinositide 3 kinases) work by switching off PI3K, an enzyme in cells that makes them grow and divide. In some cancers, PI3K is always turned on so the cancer cells continue to grow and divide uncontrollably. Researchers are studying drugs that inhibit PI3K to see if the drugs will kill cancer cells or stop them from growing.
Histone deacetylase (HDAC) inhibitors prevent cells from growing and dividing by blocking a group of enzymes called histone deacetylases. Histone deacetylases remove chemicals from proteins to affect how the cell behaves. Some types of cancer cells make too much of a histone deacetylase, which can cause the cancer to grow.
Hedgehog pathway blockers work by switching off proteins and stopping the growth of cancer cells. The hedgehog pathway is a group of proteins that sends signals to help cells grow in the right place and in the right way in a developing embryo. Hedgehog pathway proteins are normally switched off in most adult cells, but they can be switched on in some types of cancer. This causes cancer cells to grow.
Testing approved drugs for other types of cancer
There are many targeted therapy drugs available to treat cancer. But these drugs are only approved to treat some types of cancer. Researchers are testing targeted therapy drugs in other cancers that have the same abnormal genes or proteins. For example, olaparib (Lynparza) is a treatment for ovarian cancer in women with BRCA gene mutations. But it is also being studied as a possible treatment for men with prostate cancer who have the same gene mutation. Trastuzumab (Herceptin) is a treatment for breast and stomach cancers that have many HER2 proteins (called HER2-positive). But researchers are also testing trastuzumab as treatment for other types of cancers when they test positive for HER2 including colorectal cancer.
New drugs for known targets
Researchers are also looking at new targeted therapy drugs that belong to the same classes of targeted therapy drugs already used to treat some types of cancer. These drug classes include:
- proteasome inhibitors
- anti-angiogenesis drugs
- PARP inhibitors
- tyrosine kinase inhibitors
- mTOR inhibitors
New ways to design clinical trials
Personalized medicine research has taken a different approach to the design of clinical trials. Basket clinical trials test one drug that targets a mutated protein or gene in people with any type of cancer that tests positive for the mutation. Umbrella trials test several targeted therapy drugs in a group of people with different gene mutations but the same type of cancer.
A protein that speeds up certain chemical reactions in the body.
For example, enzymes in the intestines help to digest food.