54 Background: Recent trials have highlighted the clinical utility of second-line hormonal therapies for CRPC. KC, an oral inhibitor of CYP3A4 and CYP17, is commonly used in this setting. Germline SNPs in genes critical to hormone synthesis, transport, metabolism, binding sites, and degradation may contribute to variability in outcomes observed in KC treated CRPC pts. Methods: Between 1/07 and 10/08, all PCa pts seen in the Indiana University Simon Cancer Center oncology clinics were approached for recruitment to the Prostate Cancer Genetic Risk Evaluation of SNPs Study (PROGRESS). Participants completed a demographic and clinical questionnaire and provided a peripheral blood sample. Only pts with initiated on KC were included in this analysis. Germline DNA was analyzed for SNP genotyping on a 128-SNP chip using a TaqMan OpenArray GT Kit. The chip included genes critical to hormone signaling, transport, and elimination pathways with minor allele frequencies > 5%. Pts were followed for progression-free survival (PFS) and overall survival (OS) endpoints. Univariable analyses were performed to identify significant associations between SNP genotype, clinical parameters, and PFS and OS outcomes. Results: Between January 2007 and October 2008, 39 pts with CRPC initiated on KC therapy enrolled. Demographics included: age (median) – 70 yrs, prostate specific antigen (PSA) (median) – 13.0 ng/ml, PSA doubling time (median) – 2.9 months, metastatic –85%, ECOG PS 0– 74%. Age < 70 was associated with shorter PFS (p=0.010) and age > 70 was associated with shorter OS (p=0.030). SNPs significantly associated with PFS and OS are summarized in the table. Conclusions: Interpatient differences in hormonal pathway germline SNPs may contribute to variability in clinical outcomes in pts treated with KC. [Table: see text] No significant financial relationships to disclose.
Development of Novel Secondary Hormonal Therapies for Castrate-Resistant Prostate Cancer