An Exploratory Safety Study to Investigate the Extent of Tumor Cell Mobilization (TCM) After Use of G-CSF Alone or G-CSF Plus Plerixafor in Multiple Myeloma (MM) Patients Who May be Poor Mobilizers of Stem Cells

Inclusion Criteria: * Patients with a diagnosis of MM in partial response or complete response, who are undergo an autologous hematopoietic stem cell transplantation and could be considered potentially poor mobilizers. Exclusion Criteria: * Does not have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1. * Has a history of any acute or chronic leukemia (including myelodysplastic syndrome). * Had prior allogeneic or autologous transplantation. * Less than 3 to 6 weeks since last anti-cancer therapy. * Chemotherapy for mobilization is not allowed. * Has bone marrow involvement \>10% assessed based on the most recent bone marrow aspirate or biopsy performed prior to first dose of G-CSF. * Was treated with G-CSF or other cytokine within 14 days prior to the first dose of G-CSF for mobilization. * Has previously received plerixafor. * Is known to be HIV positive. * Has active hepatitis B or hepatitis C. * Has an acute infection within 24 hours prior to dosing or antibiotic therapy within 7 days prior to the first dose of G-CSF. * Has hypercalcaemia as evidenced by \>1 mg/dL above upper limit of normal (ULN). * Previously received investigational therapy within 4 weeks of screening in this protocol or currently enrolled in another investigational protocol during the mobilization phase. * Has central nervous system involvement including brain metastases or leptomeningeal disease. * Has an electrocardiogram (ECG) or study result indicative of cardiac ischemia or a history of clinically significant rhythm disturbance(arrhythmias), or other conduction abnormality. * Has co-morbid condition(s), which may render the patient at high risk from treatment complications or impairs his/her ability to comply with the study treatment and protocol. * Has a white blood cell (WBC) count \<2.5 x 10\^9/L. * Has an absolute neutrophil count (ANC) \<1.5 x 10\^9/L. * Has a platelet count \<100 x 10\^9/L. * Has an estimated creatine clearance ≤50 mL/min. * Has aspartate aminotransferase/serum glutamic oxaloacetic transaminase (AST/SGOT), alanine aminotransferase/serum glutamic pyruvic transaminase (ALT/SGPT), and total bilirubin ≥2.5 x ULN. * Does not have adequate cardiac, and pulmonary function sufficient to undergo apheresis and transplantation. * Pregnant or breastfeeding women. * Does not agree to use a highly effective method of contraception while on study treatment and for at least 3 months following study treatment.