The results of the phase 3 clinical trial of dasatinib (Sprycel) plus docetaxel/prednisone versus placebo and docetaxel/prednisone in men with castration-resistant metastatic prostate cancer (CRPC) are expected soon.

BMS recently updated the clinicaltrials.gov website to show that the dasatinib phase 3 randomized prostate cancer “READY” trial (NCT00744497) of 1500 men completed data collection in August.

Data is expected before year end and, If positive, could be a late breaker at the ASCO Genitourinary Cancers Symposiusm (ASCO GU) in Orlando from Feb 14-16, 2013.

Dasatinib inhibits Src-family kinases (SFK)

Dasatinib is approved for Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia and Ph+ acute lymphoblastic leukemia (ALL). It is a BCR/ABL, LYN and Src family tyrosine kinase inhibitor.

Src-family kinases (SFK) are involved with tumor proliferation and bone metabolism.

In the phase 1 & 2 clinical trials of dasatinib with docetaxel, many of the men with prostate cancer saw a decrease in PSA from baseline, reduction in tumor size and bone scan improvement and stabilization. Encouraging early results led to the start of a phase 3 randomized trial of dasatinib in combination with the chemotherapy, docetaxel.

However, the results for Src inhibitors in prostate cancer have been mixed to date, with not all agents generating positive data. Astra-Zeneca’s saracatinib (AZD0530), for example, showed little clinical effect on its own in a phase 2 prostate clinical trial.

It has been suggested by KOLs at numerous conferences that Src inhibitors may potentially be more effective in combination with other cancer agents. Data suggests that Src might be a resistance mechanism to enzalutamide (MDV3100), so it would be interesting to see whether a dasatinib/enzalutamide combination may be more effective than enzalutamide on its own.

Meanwhile, we await the data to see whether the combination of dasatinib with docetaxel generates a significant increase in overall survival over docetaxel alone. While some are “hopeful”, Dr Oliver Sartor, Professor of Cancer Research at Tulane Medical School noted in a prostate cancer session at ESMO 2012 that, “the docetaxel-combination graveyard is big!”

Update Jan 26 2013: Dasatinib Phase 3 Data at ASCO GU

Results from the dasatinib phase 3 prostate cancer trial are a late breaking abstract at the 2013 ASCO Genitourinary Cancer Symposium (ASCO GU) in Orlando. The data will be presented on February 14 by John Araujo MD PhD, Assistant Professor in the Department of Genitourinary Medical Oncology at The University of Texas MD Anderson Cancer Center in Houston.

LBA #8: Overall survival (OS) and safety of dasatinib/docetaxel versus docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC): Results from the phase III READY trial.

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