In this section, the success of targeted therapies that have proven effective in the last 20 years in metastatic prostate cancer is highlighted. Prostate cancer is one of the three most common cancers among men worldwide, and new treatment options are still being investigated. PARP (polyadenosine diphospate ribose polymerase) inhibitors might contribute clinical benefit in the treatment of homologous recombinant repair (HRR) alterations especially BRCA1/2 . The basis of its working mechanism is “synthetic lethality” and it is an effective treatment that has received FDA approval in the treatment of metastatic prostate cancer, with numerous studies conducted in this field.