Dexamethasone Prior to Re-treatment With Enzalutamide in Treating Patients With Metastatic Hormone-Resistant Prostate Cancer Previously Treated With Enzalutamide and Docetaxel (DEXTER)
Hormone-Resistant Prostate Cancer, Metastatic Prostate Carcinoma, Prostate Adenocarcinoma

About this trial
This is an interventional treatment trial for Hormone-Resistant Prostate Cancer
Eligibility Criteria
Inclusion Criteria:
- Patients must have histologically or cytologically confirmed adenocarcinoma of the prostate
- Patients must have metastatic disease radiographically documented by CT/magnetic resonance imaging (MRI) or bone scan; measurable disease is not necessary for inclusion
- Eastern Cooperative Oncology Group (ECOG) performance status =< 2 (Karnofsky >= 60%)
- Life expectancy of greater than 3 months in the opinion of the investigator
- Absolute neutrophil count >= 1,500/mcL
- Platelets >= 100,000/mcL
- Hemoglobin >= 8; transfusion is allowed
- Total bilirubin =< 1.5 x institutional upper limit of normal
- Aspartate aminotransferase (AST)(serum glutamic oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT)(serum glutamate pyruvate transaminase [SGPT]) =< 2.5 x institutional upper limit of normal
- Creatinine clearance >= 30 by Cockcroft-Gault formula
- Patients must have progression after prior treatment with Enza at any point in the disease course (pre- or post-chemotherapy)
- Patients must have progressed after prior treatment with docetaxel; docetaxel must have specifically been given for castration-resistant metastatic disease
- Prior treatment with other second line hormone therapy is allowed (e.g. flutamide, bicalutamide, nilutamide, ketoconazole, abiraterone, ARN-509); patients must be off these therapies for at least 4 weeks prior to starting treatment
- Prior treatment with Xofigo (223Radium), Provenge, mitoxantrone and cabazitaxel is allowed
- Patients must have rising PSA on two successive measurements, at least 2 weeks apart
- Patient must be treated with continuous androgen ablative therapy (e.g. goserelin, leuprolide, triptorelin, or degarelix, if he has not had prior surgical castration) and have castrate levels of testosterone (< 50 ng/dL or 1.7 nmol/L)
- Ability to understand and the willingness to sign a written informed consent document
Exclusion Criteria:
- Patients who have had chemotherapy or radiotherapy within 4 weeks prior to entering the study or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier (persistent toxicity >= grade 1)
- Patients who have received any other investigational agents within the last 4 weeks
- History of allergic reactions attributed to compounds of similar chemical or biologic composition to Dex or Enza
- Any use of systemic corticosteroids in the prior 4 weeks
- Uncontrolled diabetes mellitus
- History of seizure, underlying brain injury with loss of consciousness, transient ischemic attack within the past 12 months, cerebral vascular accident, brain metastases, and brain arteriovenous malformations
- Patients receiving any medications or substances that are inhibitors or inducers of cytochrome P450 family 2, subfamily C, polypeptide 8 (CYP2C8) are ineligible (e.g. gemfibrozil, rifampin, trimethoprim, pioglitazone)
- Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations or geographical condition that would limit compliance with study requirements
Sites / Locations
- Johns Hopkins University/Sidney Kimmel Cancer Center
Arms of the Study
Arm 1
Experimental
Treatment (dexamethasone and enzalutamide)
Patients receive dexamethasone PO once daily on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity until there is evidence of PSA progression, clinical disease progression, or radiographic disease progression. At time of progression, dexamethasone will be stopped via a rapid taper over one week if patients were treated for over 30 days. Patients then receive enzalutamide PO once daily on days 1-28. Treatment repeats every 28 days for up to 3 courses in the absence of clinical disease progression or unacceptable toxicity.