Cancer growth blockers

Tyrosine kinase inhibitors (TKIs) block chemical messengers (enzymes) called tyrosine kinases. Tyrosine kinases help to send growth signals in cells, so blocking them stops the cell growing and dividing.

Cancer growth blockers can block one type of tyrosine kinase or more than one type. TKIs that block more than one type of tyrosine kinase are called multi TKIs.

Single TKI

Multi TKI

Examples of TKIs include:

• axitinib (Inlyta)

• dasatinib (Sprycel)

• erlotinib (Tarceva)

• imatinib (Glivec)

• nilotinib (Tasigna)

• pazopanib (Votrient)

• sunitinib (Sutent)

You take these TKIs as tablets or capsules, usually once or twice a day.

Go to the list of cancer drugs

Proteasomes are tiny, barrel shaped structures found in all cells. They help break down proteins the cell doesn't need into smaller parts. The cell can then use them to make new proteins that it does need.

Drug treatments that block proteasomes from working are called proteasome inhibitors. They cause a build up of unwanted proteins in the cell, which makes the cancer cells die.

Doctors use proteasome inhibitors to treat myeloma. Examples include:

• bortezomib (Velcade)

• carfilzomib (Kyprolis)

• ixazomib (Ninlaro)

Read more about bortezomib

mTOR is a type of protein called a kinase protein. It can make cells produce chemicals (such as cyclins) that trigger cell growth. It may also make cells produce proteins that trigger the development of new blood vessels. Cancers need new blood vessels in order to grow. 

In some types of cancer mTOR is switched on, which makes the cancer cells grow and produce new blood vessels. mTOR blockers (inhibitors) can stop the growth of some types of cancer. 

mTOR inhibitors include:

• temsirolimus (Torisel)

• everolimus (Afinitor)

For more information about these drugs, go to our list of cancer drugs

PI3Ks are a group of closely related kinase proteins. Their full name is phospho inositide 3 kinases.

They do a number of different things in cells. For example, they act like switches in the cell turning on other proteins such as mTOR. Switching on PI3Ks might make cells grow and multiply, or trigger the development of blood vessels, or help cells to move around.

In some cancers PI3K is permanently switched on, which means that the cancer cells grow uncontrollably. Researchers have been developing new treatments that inhibit PI3K. For example, idelalisib (Zydelig) is now available as a treatment for some people with chronic lymphocytic leukaemia (CLL). Alpelisib is also available as a treatment for certain types of breast cancer.

Find out more about these cancer drugs

Histone deacetylase inhibitors are also called HDAC inhibitors or HDIs.

They block the action of a group of enzymes that remove chemicals called acetyl groups from particular proteins. This can stop the cancer cell from using some ​genes​ that would help it to grow and divide. This might kill the cancer cell completely.

HDACs are a newer type of cancer growth blocker. Panobinostat is an example of an HDAC. It is a treatment for myeloma. Researchers are looking at some other HDACs including:

• vorinostat

• romidepsin

Find a clinical trial

Hedgehog pathway blockers are drugs that target a group of proteins known as the hedgehog pathway. In the developing embryo, these proteins send signals that help cells to grow in the right place and in the right way.

The hedgehog pathway can also control the growth of blood vessels and nerves. In adults, hedgehog pathway proteins are not usually active. But in some people, changes in a gene switch them on. Hedgehog pathway blockers are designed to switch off the proteins and stop the growth of the cancer.

Vismodegib (Erivedge) is an example of a hedgehog pathway blocker. It is used in some situations to treat people with basal cell skin cancer that has spread.

BRAF inhibitors directly block a protein called BRAF. BRAF is a chemical messenger (enzyme) that controls how cells grow and send signals.

Some cancers have a change (mutation) in the BRAF gene. This genetic change makes the cancer cells produce too much BRAF protein, which can make cancer cells grow. BRAF inhibitors block the BRAF proteins and can stop cancer cells growing.

BRAF inhibitors are a treatment for advanced melanoma. Examples include:

• vemurafenib (Zelboraf)

• dabrafenib (Tafinlar)

• encorafenib (Braftovi)

Encorafenib is also a treatment for bowel cancer.

The BRAF protein can affect other proteins, such as MEK, which makes cancer cells divide and grow in an uncontrolled way. MEK inhibitors are another type of targeted cancer drug. They work by blocking the MEK protein, which slows down the growth of cancer cells. Two MEK inhibitors for melanoma are:

• trametinib (Mekinist)

• binimetinib (Mektovi)

You usually have a BRAF inhibitor with a MEK inhibitor. This is because having the combination of both drugs can work better. 

You might have dabrafenib and trametinib together for non small cell lung cancer (NSCLC) and melanoma skin cancer.

Some people might have encorafenib with binimetinib for melanoma skin cancer.

Cyclin dependant kinases are enzymes that play an important part in the development and life of a cell, also known as the cell cycle. They also have other roles within the body such as converting glucose.

There are different CDKs and they are identified by numbers.

CDK 4 and CDK 6 proteins stimulate cancer cells to divide and grow. CDK inhibitors work by blocking these proteins. It aims to slow or stop the growth of the cancer.

At the moment there are only three CDK 4 and CDK 6 inhibitors these are:

• abemaciclib

• palbociclib

• ribociclib

You take these drugs as tablets.

They are only for a type of breast cancer that is ​hormone receptor positive (HR+) and ​human epidermal growth factor receptor negative (HER2-)​. You have tests on your breast cancer cells to check for this.

Researchers are looking at other CDK proteins such as a drug called dinaciclib. It blocks CDK 9. They are looking at it for lung, breast and chronic lymphocytic leukaemia (CLL).