Inclusion Criteria:

• Must be able to comply with the protocol requirements
• Must voluntary sign the informed consent before performance of any study-related procedure not part of normal medical care
• Age ≥ 18 years

• Patient recently diagnosed with smoldering Multiple Myeloma with high risk of progression to symptomatic Multiple Myeloma defined as follows:

  • Bone Marrow infiltration ≥ 10% CPs and M component Ig G ≥ 3 g/dl or Ig A ≥ 2 g/dl or Bence Jones Protein > 1 g/dl and absence of: hollowed out areas of bone, Hypercalcemia (Calcium-serum < 11.5 mg/dl), Renal Failure (creatinine < 2 mg/dl) and anaemia (Hb > 10 g/dl or at least 2g/dl under normal value.

  • Alternatively, patients with Bone Marrow infiltration with CPs ≥ 10 %, or Ig G ≥ 3 g/dl or Ig A ≥ 2 g/dl or Bence Jones Protein > 1 g/24h (but not the two of them together) and always without: lytic lesions, Hypercalcaemia, Renal Failure and Anaemia could be admitted with the following additional criteria:

    • % CPs abnormal (CPa/CpcMO) ≥ 95 % with immunodeficiency, defined as diminution of levels of one or two Immunoglobulins of more than 25% respect normal values.
• ECOG >= 2.
• The patient has to be able to complain with the protocol visits.
• Women of childbearing age must have a negative pregnancy test during the 14 days before first dose. And they must accept to use anticonceptive methods beginning during all the study until 4 weeks after the last one.

Exclusion Criteria:

• Any other organic or mental illness that could make impossible to sign the Inform consent.
• Patients previously received treatment to smoldering Multiple Myeloma.
• Pregnancy or breast-feed women
• Hollowed out areas of bone, anaemia, renal failure and Hypercalcemia

• The following laboratory data:

  • Absolute neutrophil count ≥ 1000/mm3
  • Platelet count ≥ 75000/mm3
  • Aspartate transaminase (AST) or Alanine transaminase (ALT ) ≤ 3 x the upper limit of normal.
  • Total bilirubin: ≤ 2 x the upper limit of normal.
• Patients with >= Grade 2 peripheral neuropathy within 14 days before enrolment.
• Patient with a previous clinical history of another malignant illness except for squamous cell carcinoma or skin cancer or cervical cancer except the patient could be free of symptoms during ≥ 5 years.
• Patient has hypersensitivity or adverse events previous to lenalidomide or Dexamethasone.
• Patient who has major surgery during the 4th weeks previous inclusion.
• Patient has received other investigational drugs within 30 days before enrolment.