Side effect management algorithms for niraparib/abiraterone acetate in prostate cancer.

Introduction: Niraparib, a PARP1/2 inhibitor, is newly approved in combination with abiraterone acetate (AA) plus prednisone or prednisolone (niraparib/AA+P) for the treatment of adult patients with BRCA-mutated, treatment-naïve metastatic castration resistant prostate cancer (mCRPC). Detailed guidance beyond the prescribing information may be helpful in managing the side effect profile and dosing practicalities of this combination therapy.

Materials and methods: A panel of specialists convened to design management algorithms for four common niraparib/AA+P treatment-related adverse events (AEs) in mCRPC; anemia, thrombocytopenia, hypertension, and nausea. The algorithms build on Health Canada-approved prescribing information to highlight practical considerations related to monitoring, treatment adjustment, and specialist referral to support clinical practice.

Results: The panel's recommendations were largely aligned with the niraparib/AA+P product monograph. Single agent AA+P followed by reintroduction niraparib/AA+P using the low dose formulation of niraparib/AA were common strategies for managing higher grade AE's. Recommendations for hypertension management were expanded to include a sequence of anti-hypertensive medication trials prior to a change in anti-cancer therapy, where feasible.

Conclusion: These algorithms are intended to provide practical assistance to Canadian clinicians managing the most common AEs encountered with the novel combination, niraparib/AA+P, for mCRPC.