Researchers are constantly working to discover new therapies for ovarian cancer, fallopian tube cancer, and peritoneal cancer (cancer of the lining of the abdomen). One potential new treatment on the horizon is immunotherapy — drugs that work with the immune system to fight cancer.

So far, no immunotherapy treatments have been approved specifically for ovarian cancer. Research into multiple options is ongoing. Although immunotherapy treatments for ovarian cancer are still in the early stages, doctors hope that in the future, more people with ovarian cancer will benefit from this therapy.

What Is Immunotherapy?

Immunotherapy treatments work with the body’s natural defenses — the immune system. The immune system’s job is to fight off germs like bacteria and viruses and get rid of the toxins they make. It is made up of:

• White blood cells — Cells that recognize and attack harmful substances and make antibodies (proteins that help detect and kill germs)
• Lymph nodes — Glands that filter germs and waste out of the body
• Organs like the bone marrow, thymus, spleen, and skin — Tissues that can prevent germs from entering the body and create, store, or support immune cells

The immune system can also destroy cancer cells. However, some tumors can hide from or deactivate immune cells, making it harder for the body to fight back against cancer. Immunotherapy treatments boost the immune system’s ability to recognize and destroy cancer cells.

Immunotherapy works a little differently than other types of cancer therapies:

• Traditional chemotherapy drugs are toxic substances that damage cancer cells as well as the body’s normal cells.
• Targeted therapies block genes or proteins that cancer cells rely on to survive. They also prevent cancer cells from making new copies of themselves. These treatments often avoid harming healthy cells.
• Hormone therapies lead to lower levels of hormones in the body, which ovarian cancer cells sometimes use as fuel to grow.

Types of Immunotherapy

Researchers are studying a few different types of immunotherapies that may help treat ovarian tumors. These medications may eventually be able to treat ovarian cancer alongside current cancer treatments. Alternatively, they may be a good option when ovarian cancer becomes resistant to other treatments like chemotherapy.

Immune Checkpoint Inhibitors

Some immune checkpoint inhibitors can help treat certain cases of ovarian cancer. These drugs can stop cancer cells from deactivating the immune system.

T cells are a type of immune cell naturally found in the body. They can help fight cancer, but they also can damage the body’s healthy cells. To prevent this, T cells contain a protein called PD-1 that acts as an “off switch.” Healthy cells in the body can trigger this switch, turning “off” the T cell and preventing it from harming normal tissue. However, some cancer cells also develop the ability to activate this switch, which prevents immune cells from attacking the tumor.

Researchers have developed a drug called Keytruda (pembrolizumab) that prevents cancer cells from triggering the PD-1 off switch. This medication allows the T cells to continue doing their job fighting cancer.

Pembrolizumab has not been approved by the U.S. Food and Drug Administration (FDA) specifically as an ovarian cancer therapy. However, the FDA has approved the drug as a treatment for any type of solid tumor that contains certain gene changes that make it harder for cancer cells to heal from damage. Some people with advanced cancer of the ovary, fallopian tube, or peritoneum may be able to use pembrolizumab if their cancer has a gene change called microsatellite instability (MSI) or has mutations in mismatch repair (MMR) genes.

Adoptive Cell Therapy

Adoptive cell therapy (ACT) is a treatment that boosts the ability of immune cells to fight cancer. There are two related types of ACT:

• T cell receptor-engineered T-cell therapy, or TCR-T
• Chimeric antigen receptor T-cell therapy, or CAR-T

During these treatments, doctors remove a person’s T cells, change the T cells’ genes to make them better able to fight the person’s cancer, and then put the T cells back in the body.

Several clinical trials testing ACT are in progress. Researchers are studying both TCR-T therapy and CAR-T therapy in people with ovarian cancer.

Cancer Vaccines

Many types of vaccines help prevent a person from getting a certain illness, including some types of cancer. Other types of vaccines can be used as a treatment, after a person has already been diagnosed with cancer.

Cancer vaccines can teach the immune system to fight cancer. Molecules called cancer-specific antigens can often be found on the outside of tumor cells. The immune system uses these antigens as a signal to destroy the tumor cells. A cancer vaccine tells the immune system to attack cells that contain a particular cancer-specific antigen.

Researchers are currently studying whether cancer vaccines can be used to treat ovarian cancer. Some early studies show that this type of treatment may be useful in the future. Much more research needs to be completed before cancer vaccines become an approved option for people with ovarian cancer.

Targeted Therapy Drugs

Certain targeted therapy drugs for different types of cancer can also be considered immunotherapy. They may send signals to the immune system to destroy cancer cells.

However, the targeted therapy drugs currently used to treat ovarian cancer generally don’t work this way. Instead, these drugs directly block the processes that cancer cells rely on to survive and grow. It’s possible, though, that future targeted therapies for ovarian cancer will act as immunotherapies that boost the immune system’s ability to fight tumors.

Potential Immunotherapy Side Effects

Immune checkpoint inhibitor drugs may cause side effects such as:

• Skin rash, itching, or changes in skin color
• Cough
• Nausea
• Loss of appetite
• Tiredness
• Joint pain
• Constipation or diarrhea
• New or worsened diabetes

Less common side effects of immune checkpoint inhibitors include infusion reactions, which are allergic reactions that happen while you’re receiving the drug intravenously. An allergic reaction can cause fever, chills, dizziness, and breathing problems.

These drugs also may cause the immune system to begin attacking other tissues within the body. This can result in inflammation in organs like the liver, lungs, intestines, or kidneys. If you are taking these medications, always tell your health care team about any new sensations or health changes that occur.

The Future of Immunotherapy for Ovarian Cancer

Researchers are currently studying how to develop new drugs or improve the effectiveness of immunotherapies for ovarian cancer.

One possible way to improve treatment options is to combine immunotherapy with other cancer treatments. For example, only about 10 percent to 15 percent of people with ovarian cancer see an improvement when they are treated with immune checkpoint inhibitors alone.

However, combining these drugs with targeted therapies such as PARP inhibitors has produced much better results in early stage clinical trials. Researchers are also studying immunotherapy in combination with chemotherapy and radiation therapy.

Researchers test new cancer treatment plans by first performing many laboratory and animal experiments. If this cancer research shows that a treatment is likely to be safe and effective, researchers will then test it in clinical trials. During a clinical trial, people with cancer volunteer to receive a new treatment option that they wouldn’t otherwise be able to get through their doctor. Researchers then study the effects of the treatment, many times in a direct comparison to a more standard therapy.

If you are interested in taking part in a clinical trial, talk to your health care team. Clinical trials are available for people with many ovarian cancer types and stages.

Talk With Others Who Understand

MyOvarianCancerTeam is the social network for people with ovarian cancer and their loved ones. More than 3,600 members come together to ask questions, give advice, and share their stories with others who understand life with ovarian cancer.

Are you interested in immunotherapy options for ovarian cancer? Share your experiences in the comments below, or start a conversation by posting on MyOvarianCancerTeam.