Targeted Therapy for Prostate Cancer

Targeted therapy is a type of cancer treatment that uses drugs to identify and attack cancer cells while doing little damage to normal cells. These therapies attack the cancer cells' inner workings − the programming that makes them different from normal, healthy cells. Each type of targeted therapy works differently, but they all change the way a cancer cell grows, divides, repairs itself, or interacts with other cells.

PARP inhibitors

Rucaparib (Rubraca) and olaparib (Lynparza) are drugs known as a PARP (poly(ADP)-ribose polymerase) inhibitors. PARP enzymes are normally involved in one pathway to help repair damaged DNA inside cells. The BRCA genes (BRCA1 and BRCA2) are also normally involved in a different pathway of DNA repair, and mutations in those genes can block that pathway. By blocking the PARP pathway, these drugs make it very hard for tumor cells with an abnormal BRCA gene to repair damaged DNA, which often leads to the death of these cells. If you are not known to have a BRCA mutation, your doctor might test your blood or saliva and your tumor to be sure you have one before starting treatment with this drug.

These drugs are taken twice a day by mouth as pills.

Rucaparib (Rubraca) can be used to treat advanced castration-resistant prostate cancer that has grown after taxane chemotherapy (such as docetaxel or cabazitaxel) or anti-androgens have been tried. It can be used in men with a mutation in one of the BRCA genes. This drug is given with a LHRH agonist or to men who have had an orchiectomy.

Olaparib (Lynparza) can be used to treat advanced castration-resistant prostate cancer that has grown after the hormone therapy drugs, enzalutamide or abiraterone, have been tried. It can be used in men with a mutation in one of the BRCA genes. This drug is given with a LHRH agonist or to men who have had an orchiectomy.

Side effects of PARP inhibitors

Side effects of these drugs can include nausea, vomiting, diarrhea, fatigue, loss of appetite, low red blood cell counts (anemia), constipation, skin rash, abnormal liver blood tests, low blood platelet counts, cough and shortness of breath. Rarely, some people treated with these drugs have developed a blood cancer, such as myelodysplastic syndrome or acute myeloid leukemia. Some men taking olaparib had problems with blood clots in the lungs or legs.