About targeted cancer drugs and immunotherapy

Targeted cancer drugs work by targeting the differences in cancer cells that help them to grow and survive. Other drugs help the immune system to attack the cancer. They are called immunotherapies.

When you might have targeted cancer drugs or immunotherapy

You might have targeted cancer drugs or immunotherapy for melanoma that can’t be removed with surgery (it is unresectable). Or if it has spread to another part of the body (stage 4 melanoma).

Or you might have targeted cancer drugs or immunotherapy for some stage 3 melanomas to help reduce the risk of the cancer coming back.

Stage 3 generally means that the melanoma has only spread to the nearby lymph nodes or to an area between the primary melanoma and the nearby lymph nodes. You might have targeted cancer drugs or immunotherapy:

• if melanoma cells are found in your lymph nodes after a sentinel lymph node biopsy
• after surgery to remove your lymph nodes or in-transit metastases

In-transit metastases are areas of cancer that have spread more than 2 cm from where the melanoma started but not as far as the nearby lymph nodes.

Genetic testing of your melanoma

If you are diagnosed with stage 3 or 4 melanoma, your doctor sends a sample of the melanoma for genetic testing. This is to look for changes (mutations) in genes including the BRAF gene. This genetic change makes the melanoma cells produce too much BRAF protein, which can make melanoma cells grow.

About 40 to 50 out of every 100 people with skin melanoma (40 to 50%) have a change in the BRAF gene.

If you have changes in the BRAF gene, doctors describe your melanoma as BRAF positive. If you don’t have changes, then your melanoma is BRAF negative. Knowing this can help your doctor make decisions about whether it would be helpful to give you targeted cancer drugs.

Targeted cancer drugs

Some of the targeted cancer drugs for BRAF positive melanoma work by blocking the BRAF protein. They are called BRAF inhibitors. They can slow or stop the growth of the cancer. Some of the BRAF inhibitors include:

• vemurafenib (Zelboraf)
• dabrafenib (Tafinlar)
• encorafenib (Braftovi)

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 as having the combination of drugs can work better. The usual combinations for melanoma include:

• dabrafenib with trametinib
• encorafenib and binimetinib

You take these drugs as tablets or capsules.

Drugs that help the body's immune system (immunotherapy)

Immunotherapy helps the body's natural defence system (immune system) to find and destroy melanoma cells. You have immunotherapy if your melanoma is BRAF negative. If your melanoma is BRAF positive, you may have targeted cancer drugs or immunotherapy.

The immunotherapy drugs for melanoma are:

• ipilimumab
• pembrolizumab
• nivolumab

You might have a combination of drugs such as nivolumab and ipilimumab.

You have these drugs through a drip into your bloodstream.

Other types of immunotherapy

Doctors might use another type of immunotherapy called talimogene laherparepvec (T- VEC) which they inject directly into the melanoma. It’s a weakened form of the cold sore virus. The changed virus grows in the cancer cells and destroys them. It also works by helping the immune system to recognise and attack cancer cells. 

You might have T-VEC for melanoma that can’t be removed with surgery or has spread to certain areas of the body such as the lymph nodes or skin. It treats the tumour it is injected into but may also have an effect on tumours nearby.

Doctors used to use two other types of immunotherapy drugs called interferon and interleukin 2 to treat melanoma. They don’t use these drugs very often any more.

Side effects

Side effects depend on the type of drug you are having. Some of the common side effects include:

• flu-like symptoms including a high temperature, sore throat, shivering and muscle aches
• high blood pressure
• headaches and dizziness
• bleeding
• tummy pain
• diarrhoea and constipation
• feeling or being sick
• skin problems such as a rash
• tiredness (fatigue)

T-VEC

Having T-VEC may cause some of the common side effects listed above but it can also cause a reaction at the injection site. This can make the area painful, red, bleed, swell and feel warm. It can also cause a discharge or leakage of fluid from the site. 

Immunotherapy drugs may cause inflammation in different parts of the body which can cause serious side effects. They could happen during treatment, or some months after treatment has finished. In some people, these side effects could be life threatening.

Your doctor, nurse ort pharmacist will give you advice about the drugs you are taking, what to look out for when you are at home and numbers to call if you have any side effects.

Clinical trials

Researchers continue to look at new and different combinations of targeted cancer drugs and immunotherapies to treat melanoma. Your doctor might ask you to have treatment as part of a clinical trial.