Metformin Hydrochloride and Ritonavir in Treating Patients With Relapsed or Refractory Multiple Myeloma or Chronic Lymphocytic Leukemia

This pilot clinical trial studies the side effects and best dose of metformin hydrochloride and ritonavir in treating patients with multiple myeloma or chronic lymphocytic leukemia that has returned after a period of improvement or has not responded to treatment. Metformin hydrochloride and ritonavir may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth.

PRIMARY OBJECTIVES: I. To assess the safety, tolerability and feasibility of administering metformin hydrochloride (metformin)/ritonavir combination therapy in patients with relapsed/refractory multiple myeloma or relapsed/refractory chronic lymphocytic leukemia. SECONDARY OBJECTIVES: I. To characterize the clinical activity of this two-drug combination by assessing disease response, response duration, and (in relapsed/refractory multiple myeloma \[RRMM\]) clinical benefit response. II. To assess the progression-free survival, overall survival and compliance of all patients who start the two-drug combination. III. To evaluate potential changes in health-related quality of life, as assessed by the Functional Assessment of Cancer Therapy for Multiple Myeloma (FACT-MM) and Leukemia (FACT-Leu). TERTIARY OBJECTIVES: I. To describe the plasma pharmacokinetics of metformin and ritonavir when given in combination. II. In relapsed/refractory chronic lymphocytic leukemia (RRCLL), to describe changes in pAKT, pAMPK, and MCL-1, in circulating lymphocytes in response to treatment. OUTLINE: This is a dose escalation study. SINGLE AGENT STAGE: Patients receive metformin hydrochloride orally (PO) twice daily (BID) on days 1-7 in the absence of disease progression or unacceptable toxicity. COMBINATION REGIMEN STAGE: Patients receive metformin hydrochloride PO BID and ritonavir PO BID on days 1-7. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days and then every 28 days.