A biomarker panel containing circulating tumor cell number (CTC) and lactate dehydrogenase (LDH) level was shown to be a surrogate for survival at the individual-patient level in patients with metastatic castration-resistant prostate cancer (mCRPC) receiving abiraterone acetate plus prednisone or prednisone alone, a new study published online early in theJournal of Clinical Oncology has found.

During the COU-AA-301 study, a multinational, randomized, double-blind phase III trial comparing abiraterone acetate plus prednisone versus prednisone alone in patients with mCRPC previously treated with docetaxel, researchers sought to examine CTCs alone and in combination with other biomarkers as a surrogate for overall survival.

Results showed that a biomarker panel using CTC number and LDH level could act as a surrogate for survival. There was a significant survival difference between the abiraterone acetate plus prednisone and prednisone-alone groups (P = 0.034).

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Researchers found that 2-year survival was 46% and 2% for patients with CTCs less than 5 (low risk) versus patients with CTCs at least 5 cells/7.5 mL of blood and LDH greater than 250 U/L (hisk risk) at 12 weeks.

The authors note that additional trials are ongoing to confirm these findings.


  1. Scher HI, Heller G, Molina A, et al. Circulating tumor cell biomarker panel as an individual-level surrogate for survival in metastatic castration-resistant prostate cancer. J Clin Oncol. 2015. [Epub ahead of print]. doi: 10.1200/JCO.2014.55.3487.