Detection of Poor Mobilizer (PM) in Multiple Myeloma (MM) Patients

Inclusion Criteria: 1. Newly diagnosed transplant eligible MM patients 2. Measurable disease as defined by the presence of M-protein in serum or urine, or abnormal free light chain ratio 3. Eligible and planned for HDT and autologous haematopoietic stem cell transplantation 4. ≥18 years of age 5. Patients or their legally authorized representatives must provide written informed consent 6. Mobilization performed with G-CSF 2-4 g/m2 of cyclophosphamide and Plerixafor On Demand if considered needed based on center policies 7. Patients can be included in interventional clinical trials 8. Karnofsky performance status ≥ 60% 9. Total bilirubin \< 1.5 upper limit of normal (ULN) 10. AST/SGOT and ALT/SGPT \< 2.5 upper limit of normal (ULN) 11. Serum creatinine \< 2 upper limit of normal (ULN) 12. WBC count ≥2.5x109/L 13. ANC count ≥1.5x109/L 14. Platelet count ≥75x109/L 15. Adequate cardiac, renal, and pulmonary function sufficient to undergo apheresis and transplantation, i.e., eligible by institutional standards for autologous stem cell transplant 16. Women are not breast feeding and not pregnant 17. A negative pregnancy test is required for women in child-bearing age; patients must agree to use an adequate method of contraception whilst on study treatment and for 3 months following plerixafor treatment Exclusion Criteria: 1. Relapse/refractory MM patients 2. Non secretory MM 3. Primary plasmacell leukemia. 4. Age \< 18. 5. Prior allogeneic or autologous transplantation. 6. Prior failed mobilization attempt. 7. Inability to tolerate PBPC harvest. 8. Peripheral venous access not possible. 9. Pregnant or nursing women or patients unwilling to have adequate contraception up to 3 months after end of treatment with plerixafor 10. Clinical active infectious hepatitis type A, B, C or HIV 11. Acute infection (febrile, i.e. temperature \> 38°C) within 24 hours prior to dosing or antibiotic therapy within 7 days prior to the first dose of GCSF. 12. Left ventricular ejection fraction \< 50%. 13. Splenectomised or splenic irradiation. 14. Psychiatric, addictive, or any disorder/disease which compromises ability to give truly informed consent for participation in this study and renders the patient at high risk from treatment complications or impairs the ability to comply with the study treatment and protocol. 15. Treatment with G-CSF or other cytokine within 2 weeks prior to the first dose of G-CSF for mobilization. 16. Patients previously treated with Plerixafor 17. Patients mobilised with chemotherapy other than cyclophosphamide 2 et 4 gr/m2 18. Patients mobilised with growth factors at a dose other than (5-10µg/kg)