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Ovarian Cancer and Targeted Therapy

Medically Reviewed by Brunilda Nazario, MD on May 12, 2021

Targeted therapy is a type of ovarian cancer treatment that uses drugs to identify specific and unique features of cancer cells to attack them. It does this without causing much damage to healthy normal cells. Your doctor may use it as a standalone therapy or along with other cancer treatments like surgery, chemotherapy, or radiation therapy.

How Does Targeted Therapy Work?

When changes affect the genes in your cells, they tend to behave differently compared with healthy, normal cells. The changes can cause the cells to divide, multiply quickly, grow rapidly, repair themselves, and even interact or communicate with other cells to do similar things. This is what makes a cell “cancerous.”

But research shows that not all cancer cells are the same. For example, even if you and many others have the same type of cancer, the gene changes that happen in each person’s cancer cells may be different. They can produce unique proteins or enzymes that tell the cancer cell how it should copy itself and grow in your body.

This is where targeted therapy comes in. It’s designed to “target” certain cancer cells, take control, attack, and destroy them.

The drugs are built to know and target cells if they have:

  • Too much of a certain type of protein on a cancer cell
  • A type of protein that other normal cells don’t have
  • Mutated proteins on the cancer cell
  • Genetic changes in the makeup of the DNA that doesn’t show up on normal cells

When the drugs do find the cells they’re targeting, they work to:

  • Block or turn off chemical signals that tell cancer cells to multiply
  • Change proteins within the cancer cells. This kills them.
  • Stop making new blood vessels to feed the cancer cells
  • Make your immune system attack and kill the cancer cells
  • Deliver toxins to cancer cells to kill them but leave normal cells alone

Targeted therapy drugs, unlike chemo that kills existing cancer cells, can stop new ones from forming in your body.

Right now, this therapy is used to treat several types of cancer including ovarian cancer. But as experts learn more about cancer cell behavior, more drugs may become available.

Targeted Therapy Drugs

Depending on the type of drug, your doctor may give it to you through your veins (you may hear it called an intravenous or IV drug) or as pills that you take by mouth.

Different types of targeted therapy drugs and their uses include:

Bevacizumab (Avastin). This drug is part of a class of targeted therapy drugs called angiogenesis inhibitors. In order for cancerous cells to divide and multiple, they form new blood vessels to feed off of and grow. This is called angiogenesis.

Bevacizumab targets a protein called VEGF that triggers new blood vessels to form to feed the tumor. The drug helps slow, stop, or shrink the cancer growth. It works well for advanced epithelial ovarian cancer. You get bevacizumab as an IV infusion every 2 to 3 weeks.

Experts say bevacizumab works well when paired with chemotherapy. The duo can shrink or stop tumor growth. You might get bevacizumab along with other targeted therapy drugs if you have the BRCA gene, which can boost your chances of getting breast or ovarian cancer.

This type of treatment can stop your tumor or cancer cells from growing more or spreading. But while bevacizumab can help shrink or stop cancer growth for some, it can’t extend your life.

With this drug, you may have some side effects. They can include:

In some cases, you may have severe side effects like holes in your colon called perforations. It can also lead to abnormal opening between two body parts like your bowel and your skin or bladder. This is called a fistula. If this happens, it can cause serious infections and you may need surgery to fix it.

If you notice any of the side effects, tell your doctor. If necessary, they can switch your treatment plan and find something that works better for you.

PARP Inhibitors. Poly (ADP-ribose) polymerase inhibitors, or PARP inhibitors, are a class of drugs that stop or block PARP enzymes, a type of protein, from repairing damaged DNA inside cancer cells. When the cells aren’t able to fix themselves, they die.

The BRCA1 and BRCA 2 genes also play a role in repairing cell DNA. But if you have the mutated version of this gene, you’re more likely to get ovarian cancer. If you do have it, the PARP inhibitors target the mutated cells and block the DNA repair which makes it hard for your tumor or cancer cells to grow.

PARP inhibitor drugs include:

You’ll take these drugs by mouth as pills or capsules. However, the type of PARP inhibitor your doctor prescribes depends on whether you have a mutated BRCA gene or not. If you’re not sure you have one, the doctor can check for it by testing your blood, saliva, or tumor.

These targeted drugs have been shown to shrink, slow, or stop the growth of tumors in some advanced ovarian cancers.

Depending on how you respond to your cancer treatment and the stage of your cancer, the doctor may choose a specific PARP inhibitor that you can get:

  • Alongside chemotherapy
  • With bevacizumab
  • After they’ve tried several types and rounds of chemotherapy
  • If your ovarian cancer comes back 6 months after your last chemo

Side effects of PARP inhibitors can include:

It’s rare, but PARP inhibitors can cause certain blood cancers like myelodysplastic syndrome or acute myeloid leukemia.

Targeted Drugs for NTRK Gene Changes

A few people with ovarian cancer may have cells with mutations in the NTRK gene (neurotrophic tyrosine receptor kinase). This produces a protein called TRK that can cause abnormal growth in cancer cells.

Entrectinib (Rozlytrek) and larotrectinib (Vitrakvi) are two types of targeted therapy drugs used to stop or block the TRK protein. These are pills you take by mouth one or two times a day. These drugs aren’t used that often -- your doctor may look into them if you have an advanced type of ovarian cancer with NTRK gene changes and you don’t respond well to other types of treatments.

Side effects of these drugs can include:

Side effects like heart problems, confusion, or abnormal liver tests are less common but may happen.

Things to Keep in Mind

It’s important to take the targeted therapy drugs exactly as your doctor prescribes them. If you’re unsure, ask the doctor for instructions. Taking them correctly can affect how well they work to target cancer cells and kill them.

If you have any issues taking oral anti-cancer pills or capsules at home or notice a reaction, tell your doctor or cancer care team as soon as possible.

If you’re feeling sick from your cancer treatments and you can’t keep the pill down because of nausea, let your doctor know before you stop taking it or miss a dose. They may be able to switch or change up your treatment plan or dosage to find out what works best for you.

WebMD Medical Reference

Sources

SOURCES:

American Cancer Society: “Getting Targeted Cancer Therapy,” “How Targeted Therapies Are Used to Treat Cancer,” “Targeted Therapy for Ovarian Cancer,” “Targeted Cancer Therapies,” “Targeted Therapy.”

National Cancer Institute: “BRCA Gene Mutations: Cancer Risk and Genetic Testing, NTRK gene fusion,” “Targeted Therapy to Treat Cancer.”

Cancer Research UK: “PARP inhibitors.”

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