Background: Docetaxel based therapy in metastatic castrate resistant prostate cancer (mCRPC) provides an improvement in progression free survival and overall survival. However cures are extremely unlikely. A mechanism of resistance to docetaxel is due to neuroendocrine differentiation of cells. Somatostatin (sst) receptor analogs have efficacy in neuroendocrine tumors. SOM-230 is a multitargeted sst receptor analog with five times the affinity as other sst receptor analogs and maybe able to overcome docetaxel resistance. Methods: This is an open label, phase I study with cohorts of 3-6 patients to determine the maximum tolerated dose (MTD). The MTD cohort will be expanded to 12 patients to assess efficacy. The primary objective is to establish the MTD level of SOM 230 in combination with docetaxel and prednisone. The secondary objectives are to evaluate the safety, tolerability and efficacy of the combination therapy. Eligible patients are chemotherapy naïve, with histologically confirmed mCRPC, objective progression or rising PSA despite androgen deprivation therapy and antiandrogen withdrawal. Eligible patients are >18yrs with ECOG performance status < 2 and have life expectancy >12 wks. Adequate hepatic, renal and bone marrow function is required. Patients will receive SOM-230 intramuscularly every 28 days in escalating doses. Docetaxel 75mg/m² will be administered every 21 days along and prednisone at 5 mg twice daily orally. Correlatives: Circulating tumor cell counts, IGF-1 levels, and chromogranin A levels will be evaluated to assess proof of attacking the targets. Enrollment is due to start in may 2011. Conclusion: This study will determine the feasibility and tolerability of the combination of docetaxel, prednisone and SOM-230 in mCRPC and provide preliminary efficacy data. If favorable, then further investigation of this combination will be planned. Supported in part by Novartis Inc.