Digoxin for Recurrent Prostate Cancer

Inclusion Criteria:

• There must be a confirmed biochemical progression. Biochemical progression is defined as three rises in PSA levels, with each PSA determined at least 4 weeks apart, and each PSA value increase >0.2 ng/ml.
• Baseline PSA must be determined within 4 weeks of study entry. At least 3 PSA values are necessary prior to the study entry to calculate PSA doubling time (PSADT) calculator.
• Men with history of radical prostatectomy are required to have baseline PSA >1 ng/ml. Men treated with primary radiation therapy are required to have baseline PSA>2 ng/ml and greater than 150% rise from postradiation nadir.
• PSA doubling time must be between 6 and 24 months.
• All treatments including intermittent hormonal therapy must have been discontinued for > 6 months prior to study entry.
• No clinical or radiological evidence of distant metastases
• ECOG < 2 and adequate organ function
• Men with history of radical prostatectomy are required to have baseline PSA >1 ng/ml. Men treated with primary radiation therapy are required to have baseline PSA>2 ng/ml and greater than 150% rise from postradiation nadir
• Baseline PSA must be determined within 4 weeks of study entry. At least 3 PSA values are necessary to calculate PSA doubling time via PSADT calculator at: http://www.mskcc.org/mskcc/applications/nomograms/PSADoublingTime.aspx. PSA doubling time must be between 6 and 24 months.
• All previous local modalities of treatment, including radiation and surgery, must have been discontinued at least 8 weeks prior to treatment in this study. Patients may have received prior systemic chemotherapy, hormonal therapy, biologic or vaccine therapy. All systemic treatments must have been discontinued for > 6 months prior to study entry.
• Patients receiving intermittent hormonal therapy for their rising PSA state are considered eligible if testosterone level is above 150ng/dl and treatment was discontinued > 6 months and agree not to have additional injections while on study drug.
• No clinical or radiological evidence of distant metastases (excluding prostascint scan/PET in absence of radiographic disease in Bone scan, CT scan or MRI if used). Lymph node up to 2 cm size is allowed for the study.
• ECOG < 2 or Karnofsky Performance status >70% within 14 days before being registered for protocol therapy (Appendix B)
• Normal organ function with acceptable initial laboratory values:
• Absolute neutrophil count ≥ 1 x 109/L
• Platelets > 50 x 109/L
• Creatinine <1.5 mg/dL
• Bilirubin <1.5 X ULN (institutional upper limits of normal)
• AST (SGOT) and ALT (SGPT) ≤ 1.5 x ULN
• Willingness to use adequate methods of contraception throughout study participation and for at least 3 months after completing therapy

Exclusion Criteria:

• Metastatic disease or currently active second malignancy
• History of Sinus Node Disease and AV Block, Accessory AV Pathway (Wolff-Parkinson-White Syndrome), history of Acute Myocardial Infarction.
• Electrolyte imbalance (hypokalemia, hypo- or hypercalcemia, hypomagnesemia)
• Severe pulmonary disease and hypoxia
• Medical conditions such as uncontrolled hypertension, uncontrolled diabetes mellitus, active infectious hepatitis, type A, B or C, hypothyroidism or hyperthyroidism, which would, in the opinion of the investigator, make this protocol unreasonably hazardous.
• Major thoracic or abdominal surgery within the prior 3 weeks.
• Patients with GI tract disease resulting in an inability to take oral medication, malabsorption syndrome, a requirement for IV alimentation, prior surgical procedures affecting absorption, uncontrolled inflammatory GI disease (e.g., Crohn's, ulcerative colitis).
• Use of any prohibited concomitant medications: The washout period is at least 2 weeks before starting the study.
• Insufficient time from last prior regimen or radiation exposure: Systemic therapies for prostate cancer within 28 days prior to digoxin; strontium-89 within 12 weeks; bicalutamide within 6 weeks.
• Persistent Grade >2 treatment-related toxicity from prior therapy
• History of any digoxin-related or drug induced anaphylactic reaction
• Receipt of another investigational agent within 6 months of study entry. Patient must have recovered from all side effects of prior investigational therapy.