Targeted Therapy

Targeted therapy is a treatment option for many forms of cancer. Depending on the situation and specific medication, targeted therapy may be used alone or in combination with other treatments, such as surgery, chemotherapy, or radiation therapy. Researchers are discovering and studying many new targeted therapies.¹

This article covers how targeted therapy is used to treat cancer. Talk to your healthcare team about the types of targeted therapy. They can tell you whether they may be an option for you.

What is targeted therapy for cancer?

Targeted cancer therapy is a type of personalized or precision medicine. Doctors will typically perform tests on your cancer cells to see if they have specific changes. Targeted therapy can then address your specific changes.²

Targeted therapy for cancer aims to produce less damage to healthy cells than chemotherapy. This is because targeted therapy drugs act on specific features that are unique to cancer cells, helping to reduce damage to healthy cells.²

How does targeted therapy treat cancer?

Cancer starts when a gene (DNA) changes or mutates. The mutation can cause cells to make proteins that increase growth. This turns a normal, healthy cell into a cancer cell.³

There are many different genetic mutations. Your doctor will test you for these “biomarkers.” Cancer biomarkers are genes or proteins that make your cancer cells unique.³

Your doctor will test your cancer cells for biomarkers. They can then design targeted therapy to address your cancer’s biomarkers. For example, targeted therapies may:³

• Block or change specific proteins that help your cancer cells grow
• Stop the formation of new blood vessels that help your cancer cells grow
• Trigger your immune system to kill cancer cells
• Carry toxins to kill cancer cells

Targeted therapies are not available for every type of cancer. They are often used to treat breast cancer, lung cancer, and prostate cancer, but may also be used for many other cancers. Depending on the situation, targeted therapy may be used alone or with other treatments. Some are designed to make other treatments work better.¹

Types of targeted therapy

Targeted therapies are classified by how they act against cancer cells. There are over 100 targeted therapy drugs available. Some therapies act in more than 1 way. The right targeted therapy for you depends on your cancer biomarkers and other factors.¹

Targeted therapies can be:^1-3

• Monoclonal antibodies – proteins designed in a lab to target a specific cell. They are too large to enter cancer cells. They aim for targets on the surface of cancer cells.
• Small molecule drugs – chemicals made in the lab. They are small enough to enter cancer cells. They aim for targets inside cancer cells.

Angiogenesis inhibitors

Angiogenesis is the formation of new blood vessels. Cancer cells send signals to form new blood vessels nearby. This gets cancer cells the blood and nutrients they need to grow.³

Angiogenesis inhibitors stop the formation of new blood vessels. They are monoclonal antibodies that target proteins like VEGF.^3,4

Examples of angiogenesis inhibitors include:^3,4

• Avastin (bevacizumab)
• Cyramza (ramucirumab)

Antibody-drug conjugates

Monoclonal antibodies can be connected to a chemotherapy drug. The monoclonal antibody delivers chemotherapy directly to cancer cells.^3,4

Examples of antibody-drug conjugates include:^3,4

• Kadcyla (ado-trastuzumab emtansine)
• Adcetris (brentuximab vedotin)

Kinase inhibitors

Kinases are proteins inside cells that help them grow. Some kinases that play a role in cancer are BCR-ABL and EGFR. Kinase inhibitors are chemicals designed to block kinases. Blocking kinases can prevent cancer cells from growing and spreading.^3,4

Examples of kinase inhibitors include:^3,4

• Tagrisso (osimertinib)
• Gleevec (imatinib)
• Sprycel (dasatinib)

Other targeted therapies

There are many other types of targeted therapies. These include:^3,4

• Some immunotherapies
• Drugs that block other proteins, like mTOR and PARP
• Drugs that block how cells break down proteins

What are the possible side effects of targeted therapy?

Targeted therapy aims to result in fewer side effects than chemotherapy. But side effects are still possible. Your risk of side effects depends on your specific treatment and other factors.¹

The most common side effects of targeted therapy include:¹

• Bleeding or blood clots
• Diarrhea
• Dry skin or rash
• Liver changes
• Heart conditions
• High blood pressure
• Hair color loss

These are not all the possible side effects of targeted therapy. Talk to your doctor about what to expect when taking targeted therapy drugs. Call your doctor if you notice any changes that concern you.

Other things to know about targeted therapy

Before beginning treatment for cancer, tell your doctor about all your health conditions. Talk to them about any drugs, vitamins, or supplements you take.

Your healthcare team will talk to you about preparing for treatment. They will perform tests to see if targeted therapy will work. This will include biomarker testing.^1,5

Small-molecule drugs are taken as pills or capsules. Monoclonal antibodies are usually injected or infused into a vein. Treatment may happen at home or in a doctor’s office or hospital. Treatment schedules vary widely. Some targeted therapies are given in cycles. The rest period can help you recover in between treatments.^1,5

After treatment, your healthcare team will talk to you about recovery. This may involve medications to manage side effects. You may have regular check-ups to monitor your health.^1,5