Metformin Hydrochloride in Treating Patients with Relapsed Chronic Lymphocytic Leukemia or Untreated Chronic Lymphocytic Leukemia with Genomic Deletion 11q

Inclusion Criteria

• Patients should have a confirmed diagnosis of chronic lymphocytic leukemia defined as all of the following: * Absolute lymphocyte count (ALC) > 5000 * Positive for either CD19 or CD 20 together with CD23 and CD5 * Less than 55% atypical cells
• Patients who relapse after receiving a one or more courses of fludarabine, bendamustine, cytoxan, rituxan, chlorambucil, or campath based therapy
• Patients should have findings of relapse by one or both of the following: * ALC > 5000 on 2 consecutive occasions and increasing * Any increase in lymphadenopathy over best response that has persisted for more than 3 months
• Patient with confirmed del11q mutation may be included if untreated
• Eastern Cooperative Oncology Group (ECOG) performance 0‐2
• Life expectancy > 12 months
• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 2 times the upper limit of normal
• Alkaline phosphatase < 2 upper limit of normal (ULN)
• Serum conjugated bilirubin < 1.5 ULN (exception of Gilbert disease)
• Serum creatinine less than or equal to 1.5 in males, or 1.4 in female
• Glomerular filtration rate (GFR) > 59
• Ability to understand and the willingness to sign a written informed consent document
• Patient must be able to drink and eat more than 75% of their usual daily meals

Exclusion Criteria

• Patients with active chronic lymphocytic leukemia (CLL) disease requiring urgent chemotherapy
• Patients may not be receiving any other investigational agents
• Patients less than 30 days from last treatment for CLL
• History of allergic reactions attributed to metformin or other biguinides
• Known diabetes (type 1 or 2), fasting glucose > or equal to 7.0 mmol/L (126 mg/dL), or HgbA1C > 6.5
• Currently taking metformin, sulfonyureas, thiazolidenediones or insulin for any reason
• Current or planned pregnancy or lactation in women of child bearing age (confirmed by negative pregnancy test prior to start of therapy)
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection and sepsis, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements
• Conditions which would increase risk of lactic acidosis including: * Known alcoholism or ingestion of more than 3 alcoholic beverages per day * History of congestive heart failure defined as New York Heart Association (NYHA) class III or IV * History of metabolic acidosis * Ongoing or active infection concerning for sepsis or systemic inflammatory response syndrome (SIRS)