Metformin in Castration-Resistant Prostate Cancer
Condition: Prostate Cancer
MeSH terms: Prostatic Neoplasms
Intervention: Metformin
Intervention description: Taken orally twice daily each 28-day cycle, for 12 cycles
Intervention MeSH terms: Metformin
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Intervention model: Single Group Assignment
Masking: None (Open Label)
Enrollment: 21.0
Sex: Male
Healthy volunteers: No
Keywords: castration-resistant prostate cancer; insulin levels; metformin

Summary:

      Metformin is a medication that is prescribed for people with diabetes to help the body
      respond better to its own insulin and decrease sugar production by the liver. This helps
      control the body's blood sugar level and is approved by the Food and Drug Administration
      (FDA) for the treatment of diabetes. Participant's in this research study will already be
      receiving androgen deprivation therapy (ADT) for prostate cancer. ADT is considered standard
      of care for prostate cancer. Changes in the participant's metabolism, including changes in
      insulin and blood sugar levels, are often seen as a result of this type of hormone therapy.
      Some studies have shown a relationship between insulin and prostate cancer. These studies
      have suggested that insulin may signal tumor cells to grow. Other studies suggest that people
      receiving metformin treatment for diabetes may enjoy better outcomes from their prostate
      cancer then other similar patients who are not treated with metformin.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Histologically or cytologically confirmed adenocarcinoma of the prostate

          -  History of bilateral orchiectomies or ongoing treatment with a GnRH agonist for GnRH
             antagonist

          -  Disease progression according to PSA Working Group 2

          -  Minimum starting PSA (Prostate Specific Antigen) level of 2.0 ng/mL

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1

        Exclusion Criteria:

          -  Symptomatic metastases

          -  Receiving any other agents for the treatment of prostate cancer except gonadotropin
             releasing hormone (GnRH) agonist or antagonist within the last 30 days

          -  Received any investigational cancer treatment agents within the last 30 days

          -  Prior treatment with docetaxel

          -  History of diabetes requiring drug therapy

          -  Current treatment with metformin or metformin treatment within the last year

          -  History of allergic reaction to metformin

          -  Have uncontrolled intercurrent illness including, but not limited to ongoing or
             unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations
             that would limit compliance with study requirements

          -  Serum creatinine 1.5mg/dL or greater

          -  Hepatic impairment

          -  Need for ongoing treatment with cimetidine

          -  History of a different malignancy except for the following circumstances: Individuals
             with a history of other malignancies are eligible of they have been disease-free for
             at least 5 years and are deemed by the investigator to be at low risk for recurrence
             of that malignancy. Individuals with the following cancers are eligible if diagnosed
             and treated within the past 5 years: basal cell or squamous cell carcinoma of the skin