Study of Lenalidomide and Low-Dose Dexamethasone in Chinese Subjects With Relapsed/Refractory Multiple Myeloma

Inclusion Criteria: 1. Understand and voluntarily sign informed consent form 2. Age ≥ 18 years at the time of signing consent 3. Prior or current diagnosis of Durie-Salmon Stage II or III multiple myeloma AND have disease progression after at least 2 cycles of systemic anti-myeloma treatment or have relapsed with progressive disease after treatment. 4. Measurable levels of myeloma paraprotein in serum (≥ 0.5 g/dL \[5 g/L\] or urine (≥ 0.2 g excreted in a 24-hour collection sample). 5. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2. 6. Able to adhere to the study visit schedule and other protocol requirements. 7. Must agree to comply to Lenalidomide Pregnancy Prevention Risk Management Plan requirements. Exclusion Criteria 1. Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from participating in the study. 2. Subjects with non-secretory multiple myeloma by Serum Protein Electrophoresis (SPEP) and Urine Protein Electrophoresis (UPEP) assessment. 3. Pregnant or lactating females 4. Any of the following laboratory abnormalities: * Absolute neutrophil count of \< 1000 cells/mm3 (1.0 X 109/L) * Platelet count \< 50,000/mm3 (50 X 109/L) in subjects in whom \< 50% of the bone marrow nucleated cells were plasma cells * Renal failure requiring dialysis or peritoneal dialysis * Serum glutamic oxaloacetic transaminase, (SGOT)/ Aspartate-Aminotransferase (AST) \> 3.0 x upper limit of normal (ULN) * Serum total bilirubin \> 2.0 mg/dL (34μmol/L) 5. Any condition, including the presence of laboratory abnormalities, which placed subject at unacceptable risk if participating in the study or which would confound the ability to interpret study data. 6. Significant active cardiac disease within the previous 6 months. 7. Prior history of malignancies, other than multiple myeloma, unless the subject has been free of disease for ≥ 3 years. Exceptions include the following: * Basal cell carcinoma of the skin * Carcinoma in situ of the cervix * Carcinoma in situ of the breast * Squamous cell carcinoma of the skin 8. Incidental histologic finding of prostate cancer (Tumor, Node, and Metastasis \[TNM\] stage of T1a or T1b) 9. Known hypersensitivity to thalidomide or dexamethasone 10. Prior history of uncontrollable side effects to dexamethasone therapy 11. Peripheral neuropathy ≥ grade 2 12. Prior use of lenalidomide 13. Use of any standard/experimental anti-myeloma drug therapy within 28 days of the start of study drug or use of any experimental non-drug therapy (e.g. donor leukocyte/mononuclear cell infusion) within 56 days of the start of study drug) 14. Unable or unwilling to undergo antithrombotic therapy 15. History of deep vein thrombosis (DVT) or pulmonary emboli (PE) within the past 12 months 16. Known HIV positivity 17. Active infectious hepatitis A, B, or C or chronic carriers of hepatitis B with hepatitis B surface antigen (HBsAG) positive or if the hepatitis B viral deoxyribonucleic acid (HBV DNA) level is detectable by polymerase chain reaction (PCR).