Treatment of non-metastatic castration-resistant prostate cancer: facing age-related comorbidities and drug-drug interactions.

Introduction: Patients with non-metastatic castration-resistant prostate cancer (nmCRPC) are frequently poly-medicated due to age-related and androgen deprivation therapy (ADT)-derived comorbidities. In high-risk patients, androgen receptor inhibitors (ARIs) have shown to delay disease progression; however, drug-drug interactions (DDIs) with preexisting medications may impact the therapeutic effect and safety of these and of the ARIs themselves.

Areas covered: We review the potential comorbidity burden of nmCRPC patients on the basis of epidemiologic studies on age-related comorbidities, the impact of ADT and specific studies analyzing this topic. Using the DDIs compendia Lexicomp® and Drugs.com®, we provide a scenario of the potential DDIs between common mediations used to treat these comorbidities and the three currently available ARIs: apalutamide, enzalutamide and darolutamide.

Expert opinion: In high-risk nmCRPC patients to be treated with an ARI, careful multidisciplinary evaluation of potential DDIs is a fundamental component in the clinical-decision making. The lower potential for DDIs, the lower need for dose adjustment or change of current comedications and of patient monitoring, and safer introduction of new comedications. To optimize this step, an effort is still needed to determine the clinical relevance of DDIs and to harmonize their definition and classification among the different compendia.