Changes in circulating tumor cells (CTC) and markers of inflammation after sipuleucel-T treatment.

40 Background: Sipuleucel-T (SipT) prolongs survival of men with metastatic castrate-resistant prostate cancer (CRPC). We prospectively collected CTC, LDH, and inflammatory markers as part of an audit to investigate changes after SipT treatment compared to baseline. Methods: Men with CRPC had blood drawn routinely before and after SipT treatment. CTC were run using Veridex assay. LDH, C-reactive protein (CRP) and β2-microglobulin (β2m) were measured in a reference lab. Wilcoxon Signed Rank Test was used to compare pre- and post-treatment (median 3.5 weeks after final infusion) levels. Results: 61 men received SipT at USC from June 2010 to July 2012 and were included in the analysis. Median pre-SipT PSA level was 24.9 and 47% had Gleason 8-9; 20% had received chemotherapy. 18 men had detectable CTCs pre SipT (range 1-170). CTC count declined in 7 men, increased in 6 men, and stayed stable in 2 men (3 inevaluable); in 3 cases the change crossed men over from unfavorable ( >5) to favorable count. PSA decline...