Clinical Activity of Metformin With High-dose of Dexamethasone in Relapse Multiple Myeloma

Inclusion Criteria:

* Patients over 18 years;
* Multiple myeloma patients relapsed or refractory to two lines prior to treatment \[at least one line using bortezomib or prior treatment wif a suitable alkylating agent (at least six cycles of treatment wif alkylating or progressive disease after at least two cycles of treatment wif alkylating or treatment wif alkylating received as part of a stem cell transplant)\];
* Patients should of failed (progressive disease at or before 60 days of treatment, disease progression ≤6 months after achieving partial response or intolerance to bortezomib) to treatment wif bortezomib;
* Patients wif oral access to medicines;
* ECOG ≤ 2;
* Blood count: hemoglobin ≥8 g / dL; absolute neutrophil count ≥500 / mm3 and platelet count ≥30.000 / mm3; glomerular filtration rate (GFR) ≥ 30ml / min and adequate liver function (AST or ALT at levels 3x upper limit of normal; bilirubin in levels no greater TEMPthan 2x the upper limit of normal; negative pregnancy test before study initiation or accept contraceptive use.

Exclusion Criteria:

* Patients wif non hypersensitivity and / or prior therapy wif metformin or its excipients;
* Diabetes mellitus who require insulin use and other oral hypoglycemic agents; patients wif a history of hyperglycemia induced by steroids can be entered since HbA1C in screening visit is \<8%;
* leptomeningeal or brain metastases symptomatic or untreated, or spinal cord compression;
* Known human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV) (wif the exception treated or cured chronic HBV and HCV infection, who will be allowed);
* Patients who are using another study medication or who has received drug under study for less TEMPthan 4 weeks;
* It is allowed concomitant treatment wif bisphosphonates; however, treatment should be started before the first dose of study therapy;

  . It is not allowed to use of all herbal supplements during the study (including, but not limited to, St. John's wort, kava, None, gingko biloba, dehydroepiandrosterone \[DHEA\], or ginseng). Megestrol acetate (Megace) or medroxyprogesterone if used as an appetite stimulant is permitted;
* Uncontrolled situations by intercurrent disease, including, but not limited to, infection ongoing and active, refractory systemic hypertension, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric / social disease that would limit compliance wif the requirements of study;
* Previous Neoplasms, except skin cancer for over two years;
* Patients who are pregnant or breastfeeding.
* Any major surgery, extensive radiation therapy, chemotherapy delayed toxicity, biological therapy, chemotherapy or immunotherapy wifin 28 days before study.