Medical Resource Utilization (MRU) of Abiraterone Acetate Plus Prednisone (AAP) Added to Androgen Deprivation Therapy (ADT) in Metastatic Castration-Naive Prostate Cancer: Results from LATITUDE.

201 Background: AAP + ADT demonstrated significant improvements in overall survival and disease progression in the LATITUDE trial. The objective of this analysis was to assess event-driven MRU from AAP + ADT vs ADT alone. Methods: MRU data from the LATITUDE trial were obtained and consisted of medical utilization other than that mandated by protocol while patients were on treatment. MRU types included overnight hospitalizations and length of stay (LOS), emergency room (ER) visits, radiotherapy, surgery, imaging, and specialist and general practitioner (GP) visits. Rates by treatment (per 100 person-years) and rate ratios were estimated using zero-inflated Poisson regression. Difference in average LOS between treatment arms was assessed using repeated measures regression. Results: A total of 1199 patients were evaluated. Statistically significantly lower rates (24% reduction) of hospitalizations were observed with AAP + ADT compared with ADT alone (Table). The most common hospitalization reasons were bladder/urethral symptoms and infections, lung infections, and musculoskeletal/connective tissue pain. Average LOS per hospitalization episode was similar. Statistically significantly lower rates of imaging (40% reduction) and radiotherapy were also observed for AAP + ADT vs ADT alone. Rates for specialist visits, surgery ER visits, and GP visits were not statistically different. Conclusions: Adding AAP to ADT does not increase MRU and leads to lower rates of hospitalization, imaging, and radiotherapy. This likely reflects the more favorable clinical outcomes with AAP + ADT therapy. Clinical trial information: NCT01715285. [Table: see text]