The efficacy of premarin versus ketoconazole on prostate-specific antigen responses in castrate-resistant prostate cancer in Jamaica

ABSTRACT

OBJECTIVES: Premarin and ketoconazole are affordable secondary hormonal options available for castrate-resistant prostate cancer (CRPC) in Jamaica. The aim of this study was to compare the relative efficacy of both drugs to decrease prostate-specific antigen (PSA) in CRPC in a population of patients of predominantly African escent. SUBJECTS AND METHODS: This study retrospectively identified patients with CRPC that presented to the University Hospital of the West Indies (January 1, 2009-December 31, 2013) and patients from a private urology clinic (November 2, 2005-June 3, 2015). The primary endpoint was to identify the proportion of patients with a decline of ¡Ý 50% in PSA level after treatment. The relative efficacy was assessed by the time to progression (TTP), an increase in PSA of 25% above nadir with PSA progression defined by Prostate Cancer Clinical Trials Working Group2 criteria. RESULTS: Thirty-five patients diagnosed with CRPC were identified; 32 initially treated with premarin and three with ketoconazole. Nine of the patients initially on premarin were crossed over to the ketoconazole treatment roup, bringing to twelve the patients treated with ketoconazole. Decline in PSA of ¡Ý 50% was observed in 43.8% (14 of32) and 25% (3 of 12) of patients on premarin and ketoconazole, respectively. The median (95% CI) TTP for patients treated with premarin was 24.00 (19.28, 28.724)months and ketoconazole was 13.54 (1.66, 25.41) months with no statistically significant difference between the groups (p = 0.107; log rank test). CONCLUSION: The study did not identify differences in the relative efficacy between premarin and ketoconazole in treating patients with CRPC.