Targeted therapies for ovarian cancer are designed to specifically target and attack cancer cells while causing less harm to healthy cells. These drugs work by blocking the growth and spread of cancer by interfering with specific molecules involved in tumor growth. Targeted therapy may be used in combination with other treatments, like chemotherapy. 

Common targeted therapies include:

• Bevacizumab (Avastin) – belongs to a class of drugs called angiogenesis inhibitors. 
• Olaparib (Lynparza), rucaparib (Rubraca), and niraparib (Zejula) – belong to a class of drugs called PARP inhibitors.
• Mirvetuximab soravtansine (Elahere) – belongs to a class of drugs called antibody-drug conjugates (ADC).

How targeted therapies work

Targeted therapies work by attacking special features of cancer cells, which makes treatment more precise and effective. Unlike traditional treatments that affect both cancer cells and healthy cells, targeted therapies focus on stopping the cancer cells from growing and spreading.  This can be done in different ways, such as:

1. Targeting specific proteins: Some targeted therapies block proteins that cancer cells need to grow and survive.
2. Blocking blood vessel growth: Angiogenesis inhibitors, a type of targeted therapy, stop tumors from creating new blood vessels that help them grow.
3. Delivering toxic substances to cancer cells: Some therapies attach toxins to molecules that specifically target cancer cells, delivering the harmful substances directly to the cancer cells.

Benefits of targeted therapies for ovarian cancer

Targeted therapies offer several benefits, making them a hopeful option for patients with ovarian cancer. By targeting specific parts of cancer cells, these therapies can provide more effective treatment with fewer side effects. Here are some key benefits:

1. Personalized treatment: Targeted therapies can be tailored to the specific genetic makeup of an individual’s cancer, which can increase the chances of success.
2. Fewer side effects: Because they target cancer cells specifically, targeted therapies usually cause fewer side effects than traditional chemotherapy.
3. Improved quality of life: Patients often experience a better quality of life because treatment with targeted therapies because there is less impact on healthy cells.

What targeted therapies are used for ovarian cancer?

There are several types of targeted therapies. Each works to change the way a cancer cell grows, divides, repairs itself, or interacts with other cells.

Bevacizumab (Avastin)

This targeted therapy is designed to prevent the growth of new blood vessels in a tumor.  Just like platinum-sensitive cancers, it may also be recommended in combination with chemotherapy. It may also be recommended to continue treatment with bevacizumab after initial treatment for a period of time. This is called maintenance therapy which is used to help keep the cancer from coming back. 

Common side effects may include:

• high blood pressure
• fatigue
• bleeding
• low white blood cell counts
• headaches
• mouth sores
• loss of appetite
• diarrhea

PARP inhibitors

This type of targeted therapy interferes with the ability of cancer cells to repair themselves. There are currently three PARP inhibitor drugs: Olaparib (Lynparza), rucaparib (Rubraca), and niraparib (Zejula). Cancer cells often have damaged DNA, but they use PARP to fix it so they can keep growing. PARP inhibitors block this repair process, which makes it harder for cancer cells to survive.

PARP inhibitors are especially helpful for treating ovarian cancer, particularly in those who have a certain genetic mutation called BRCA, as well as those with other related genetic defects known as homologous recombination deficiency (HRD). Here’s how PARP inhibitors are used to treat ovarian cancer:

1. Maintenance therapy- after the first round of treatment, which usually includes surgery and chemotherapy, doctors may give PARP inhibitors as maintenance therapy. This means the medicine helps keep the cancer from coming back by attacking any remaining cancer cells.
2. Treatment for recurrent cancer – ovarian cancer often comes back after treatment. PARP inhibitors are effective in treating this recurrent cancer, especially for women with BRCA mutations.
3. Combination therapy – scientists are studying how to combine PARP inhibitors with other cancer treatments, like immunotherapy, to make the treatment even stronger.

Common side effects of PARP inhibitors can include:

• low red blood cells (anemia)
• low white blood cells
• low platelets
• fatigue
• nausea
• headaches
• diarrhea or indigestion
• taste changes
• liver and kidney problems

Antibody-drug conjugate (ADC)

This type of targeted therapy delivers treatment, like chemotherapy, directly to the tumor. Mirvetuximab soravtansine (Elahere) is one example of an antibody-drug conjugate. In many ovarian cancers, the cells have high amounts of a protein called folate receptor-alpha (FR-alpha) on their surfaces. These high levels may cause the cancer to be more aggressive and harder to treat.  Mirvetuximab soravtansine is a drug that targets this protein and, therefore, treats the cancer by delivering chemotherapy directly to the cancer.  This drug is given through an IV (into a vein), usually once every three weeks. 

Common side effects of this drug can include:

• nausea and vomiting
• diarrhea or constipation
• feeling tired
• belly pain
• low blood cell counts
• eye problems
• lung disease
• peripheral neuropathy

How is targeted therapy given?

Targeted therapy is given in different ways, based on the type of targeted therapy, the patient’s overall health, and the characteristics of the cancer being treated. Examples of these delivery methods for some therapies can include: 

• Oral (Pills or Tablets): Some targeted therapies, like PARP inhibitors (e.g., olaparib, rucaparib, niraparib), are taken as pills or tablets by mouth. These are usually prescribed for daily use over a specific period.
• Intravenous (IV) Infusion: Other targeted therapies, such as bevacizumab (Avastin), are administered through an IV. This means the drug is given directly into the bloodstream through a vein, typically at a hospital or clinic. The frequency of IV infusions depends on the treatment plan.
• Injection: In some cases, targeted therapies may be injected just under the skin. However, this method is less common for ovarian cancer targeted therapies.

Questions to ask your doctor

Starting targeted therapy for ovarian cancer can be overwhelming, but being well-informed can help you feel more confident and prepared. Here are some essential questions to ask your doctor that can help you understand your treatment plan and what to expect.

• What are targeted treatments, and how do they differ from traditional chemotherapy?
• Are targeted therapies an option for treating my specific type of ovarian cancer?
• Will I need to undergo genetic or biomarker testing to determine if targeted therapy is right for me?
• What specific proteins or genes (such as BRCA or FR-alpha) are involved in determining whether targeted therapy will be effective for my cancer?
• How do PARP inhibitors and other targeted treatments work, and what can I expect from them?
• What are the potential side effects of targeted therapies compared to traditional treatments like chemotherapy?
• Are there any clinical trials available for new targeted therapies that might be a good option for me?
• How long will I need to be on targeted therapy, and how will we know if it’s working?
• Are there any lifestyle changes or supportive therapies that can help manage side effects from targeted treatments?
• What is the likelihood that my cancer will respond to targeted therapy, and how does this compare to other treatment options?

Ovarian cancer treatment resources

To find more information about ovarian cancer treatment and side effects, visit these helpful resources:

• American Cancer Society – Treatment Ovarian Cancer
• National Comprehensive Cancer Network – Ovarian Cancer Treatment Guidelines
• National Ovarian Cancer Coalition – Resource Guide for Those Newly Diagnosed
• National Ovarian Cancer Coalition – Resource Guide for Women With Recurrent Disease
• You and Ovarian Cancer – Animated Patient Guide