Efficacy of enzalutamide in treatment of metastatic castration-resistant prostate cancer

Abstract:

Objective To investigate the efficacy and safety of enzalutamide as the first-line therapy for metastatic castration-resistant prostate cancer（mCRPC） and as the second-line therapy after abiraterone resistance in the real-world setting.Methods A retrospective analysis was performed for the clinical data of 26 patients with mCRPC who were admitted to The First Affiliated Hospital of Army Medical University from December 2019 to March 2023. Based on the biochemical parameters including serum prostate-specific antigen（PSA），imaging reexamination results，and follow-up records during treatment，the patients were analyzed in terms of PSA response，PSA progression，and radiographic progression，and adverse events during treatment were reported.Results A total of 26 patients with mCRPC received enzalutamide treatment，among whom 13 patients received enzalutamide as the first-line therapy for mCRPC and 13 patients who developed resistance to abiraterone acetate received enzalutamide as the second-line therapy for mCRPC. The patients had a median follow-up time of 14（4，23） months，and the patients receiving first-line therapy had a significantly higher PSA response rate than those receiving second-line therapy（100% vs. 53.8%，χ²=7.800，P=0.005）. The patients receiving the first-line therapy for mCRPC had a median PSA progression-free survival time of 18.6 months and a median radiographic progression-free survival time of 20.5 months，while the patients receiving the second-line therapy for mCRPC had a median PSA progression-free survival time of 17.4 months and a median radiographic progression-free survival time of 19.5 months. The main adverse reactions observed in the patients receiving enzalutamide included fatigue（17/26），hot flashes（3/26），and drug-induced liver injury（1/26），which had good overall tolerability in patients.Conclusion Enzalutamide treatment in mCRPC patients can effectively achieve PSA response and delay tumor progression. Enzalutamide as the first-line therapy has better overall efficacy than it as the second-line therapy after abiraterone resistance，with tolerable drug-related adverse events.