Lenalidomide Maintenance Therapy for Multiple Myeloma

* INCLUSION CRITERIA: * Patients with multiple myeloma treated with induction therapy or re-induction therapy, who at the time of study enrollment have documented evidence of stable disease response or better according to International Myeloma Workshop Consensus Panel. The response assessment must occur at least 4 weeks after completion of their last treatment. * Age greater than or equal to 18 years. Because no dosing or adverse event data are currently available on the use of lenalidomide in patients * Eastern Cooperative Oncology Group (ECOG) performance status less than or equal to 2. * Patient must have adequate hematologic, renal, hepatic, and cardiac function as defined by: * Absolute neutrophil count greater than or equal to 1.0 K/microL independent of growth factor support * Platelets greater than or equal to 75K/microL * Hemoglobin greater than or equal to 8 g/dL (transfusions are permissible) * Calculated creatinine (CrCl) clearance of greater than or equal to 40 mL/min. using the Cockcroft-Gault method. If the calculated CrCl based on Cockcroft-Gault method is * Total bilirubin less than or equal to 1.5 mg/dL, aspartate aminotransferase (AST)/ serum glutamic oxaloacetic transaminase (SGOT) and alanine aminotransferase (ALT)/ serum glutamic-pyruvic transaminase (SGPT) less than or equal to 3 times ULN * Females of childbearing potential (FCBP) must agree to use two effective forms of contraception simultaneously or to practice complete abstinence from heterosexual intercourse during the following time periods related to this study: 1) for at least 28 days before starting study drug; 2) while participating in the study; and 3) for at least 28 days after discontinuation from the study. The two methods of effective contraception must include one highly effective method (i.e. intrauterine device (IUD), hormonal \[birth control pills, injections, or implants\], tubal ligation, partner's vasectomy) and one additional effective (barrier) method (i.e. latex condom, diaphragm, cervical cap). FCBP must be referred to a qualified provider of contraceptive methods if needed. * A FCBP is defined as a sexually mature woman who: 1) has not undergone a hysterectomy or bilateral oophorectomy; or 2) has not been naturally postmenopausal for at least 24 consecutive months (i.e., has had menses at any time in the preceding 24 consecutive months). * A FCBP must have two negative serum or urine pregnancy tests prior to starting study drug. The first pregnancy test must be performed within 10-14 days prior to the start of study drug and the second pregnancy test must be performed within 24 hours prior to prescribing the study drug. The prescriptions of study drug must be filled within 7 days. * Male patients must agree to use a latex condom during sexual contact with FCBP while participating in the study and for at least 28 days following discontinuation from the study even if he has undergone a successful vasectomy. * Patient must be able to take aspirin (81 or 325 mg) daily as prophylactic anticoagulation. Patients intolerant to acetylsalicylic acid (ASA) may use warfarin or low molecular weight heparin. * Patient must understand and voluntarily sign an informed consent form, with the understanding that the patient may withdraw consent at any time without prejudice to future medical care. EXCLUSION CRITERIA: * Patients with progressive or refractory multiple myeloma (MM), as defined by International Myeloma Workshop Consensus Panel criteria. * Refractory to lenalidomide in the most recent line of therapy, as defined by the International Myeloma Consensus Panel criteria - as failure to achieve minimal response or development of progressive disease while on lenalidomide or within 30 days of lenalidomide therapy * Patients who are receiving any other investigational agents with the intent to treat myeloma. Permitted concurrent therapies include: * Bisphosphonates * Radiotherapy to single stable disease site * Plasma cell leukemia * Pregnant or lactating females. Because there is a potential risk for adverse events to nursing infants secondary to treatment of the mother with lenalidomide, lactating females must agree not to breast feed while taking lenalidomide. * Uncontrolled hypertension or diabetes * Active hepatitis B or C infection * Diagnosed or treated for another malignancy within 3 years prior to study enrollment, with the exception of complete resection of non-melanoma skin cancer, or an in situ malignancy * Previous diagnosis of another malignancy with any evidence of residual disease. * Patients seropositive for the human immunodeficiency virus (HIV), and/or those who are taking anti-retroviral treatment for HIV/acquired immune deficiency syndrome (AIDS) * Prior organ transplant requiring immunosuppressive therapy * Prior allogeneic stem cell transplant * Patients requiring continuous, systemic immunosuppressive therapy * Patients with myocardial infarction within 6 months prior to enrollment, New York Heart Association (NYHA) Class III or IV heart failure, uncontrolled angina, severe uncontrolled cardiac arrhythmias, or electrocardiographic evidence of acute ischemia * Patients with conditions that would prevent absorption of the study drug * Uncontrolled intercurrent illness including but not limited to uncontrolled infection or psychiatric illness/social situations that would compromise compliance with study requirements * Significant neuropathy greater than or equal to Grade 3 at baseline * Contraindication to concomitant anticoagulation prophylaxis * Major surgery within 1 month prior to enrollment * Patients who were previously exposed and who developed severe adverse events, hypersensitivity or desquamating rash to either thalidomide or lenalidomide