Targeted Therapy for Prostate Cancer

Targeted therapies are a treatment option for prostate cancer. They work by blocking or targeting specific parts of cancer cells. This reduces damage to healthy cells.¹

Targeted therapies are not the best treatment for everyone with prostate cancer. They may work only if you have specific genetic changes. Talk to your doctor about whether targeted therapies are right for you.¹

How does targeted therapy work for prostate cancer?

Targeted therapies attack parts of cancer cells that make them unique compared to healthy cells. This is different from chemotherapy, which attacks all fast-dividing cells. Specifically targeting cancer cells can reduce damage to healthy cells.¹

Genetic changes (mutations) are common targets of targeted therapy. Cancer cells often have certain mutations that healthy cells do not. Targeted therapies take advantage of these differences by targeting the cancer cells that have those mutations.¹

Targeted therapies to treat prostate cancer block an enzyme called poly (ADP-ribose) polymerase (PARP). PARP enzymes help repair damaged DNA. Damaged DNA must be fixed for cells to divide. Other proteins in our cells repair DNA in a different way. These proteins include the BRCA1 and BRCA2 proteins.¹

Mutations in a DNA repair gene force cells to rely more on PARP. PARP inhibitors make it harder for cells with these mutations to repair damaged DNA.¹

Examples

The US Food and Drug Administration (FDA) has approved several targeted therapy drugs to treat prostate cancer. They are all PARP inhibitors. They include:^2-6

• Rucaparib (Rubraca®)
• Olaparib (Lynparza®)
• Talazoparib (Talzenna®)
• Niraparib + abiraterone (Akeega®) (combination of a PARP inhibitor (niraparib) and an antiandrogen (abiraterone))

All of these drugs are meant to treat people with metastatic, castration-resistant prostate cancer (mCRPC). This refers to prostate cancer that has spread to other parts of the body and does not respond to treatments that lower testosterone. These drugs are meant only for people whose cancer cells have a mutation in a certain DNA repair gene.^2-5

What are the possible side effects?

Side effects can vary depending on the specific drug you are taking. Common side effects of PARP inhibitors include:^1-5

• Nausea
• Vomiting
• Diarrhea
• Fatigue
• Loss of appetite
• Low red blood cell counts (anemia)
• Low platelet counts
• Constipation
• Skin rash
• Abnormal liver blood tests
• Cough
• Shortness of breath

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

Other things to know

Take targeted therapies exactly as your doctor describes. PARP inhibitors are usually taken by mouth. They may be given with hormone therapy.¹

Your doctor may test your blood or cancer cells before prescribing targeted therapy. This can help ensure that you have certain mutations before taking a PARP inhibitor.¹

Some targeted therapies for prostate cancer can cause harm to an unborn baby. If you are taking one of these drugs, always use a condom during sex with someone who is or can get pregnant (patients should discuss appropriate birth control methods, and how long they need to use them, with their doctor).^2-5

PARP inhibitors can cause serious long-term side effects. For example, some people who take PARP inhibitors may develop certain types of blood cancer in the future. Also, people who take certain PARP inhibitors are at greater risk for blood clots. Your doctor can help you understand these risks.^1-5

Before beginning treatment for prostate cancer, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.