Editing AUA: Advanced Prostate Cancer (2023) (section)

===== Other Therapies =====
* '''<span style="color:#ff0000">PARP inhibitor</span>'''
** '''<span style="color:#ff0000">Should be offered to patients with deleterious or suspected deleterious germline (e.g. BRCA1, BRCA2, ATM, etc.) or somatic homologous recombination repair gene-mutated mCRPC following</span> prior treatment with enzalutamide or abiraterone acetate, and/or a taxane-based chemotherapy.'''
** Defects in DNA repair occur in up to 30% of men with mCRPC, and such cancer cells depend instead on PARP-regulated DNA repair. Therefore, inhibition of PARP in these tumors results in cell death
** '''<span style="color:#ff0000">Options: olaparib and rucaparib</span>'''
** Platinum based chemotherapy may be offered as an alternative for patients who cannot use or obtain a PARP inhibitor.
* '''<span style="color:#ff0000">Pembrolizumab</span>'''
** '''<span style="color:#ff0000">Should be offered in patients with mismatch repair deficient or microsatellite instability-high mCRPC.</span>'''
*** In a case series of 1,033 patients with advanced prostate cancer, 3.1% had a microsatellite instability-high (MSI-H)/mismatch repair deficient (dMMR) prostate cancer, with more than half of those treated with anti PD-1 therapy responding to treatment having a >50% decline in PSA.