Zoledronic Acid in Patients With Multiple Myeloma and Asymptomatic Biochemical Relapse

Inclusion Criteria: * Male or female patients aged ≥18 years. * Signed informed consent before performing any study procedure that is not the part of the regular medical care of the patients. * Diagnosis of MM, with biochemical relapse after initial response with no symptoms resulting from the disease (CRAB), defined as a re-positivation of a previous immunofixation (two samples) or increase above 25% of serum or urine protein M. * In the investigator's opinion, ability to meet all clinical trial requirements Exclusion Criteria: * Treatment with bisphosphonates (oral route and/or endovenous route) within 3 months prior to inclusion. * Treatment with denosumab within three months prior to inclusion. * Criteria of symptomatic disease or organic damage related to disease, defined as: * Impaired renal function: serum creatinine \>2 mg/dl or 173 mmol/l. Calcium increase: serum calcium ≥12 mg/dl within 28 days prior to inclusion. * Anaemia: haemoglobin \< 10 g/dl or 2 g/dl below normal ranges. * Bone injury: new osteolytic lesions (from diagnosis) seen within 3 months prior to inclusion, current pathological fractures or increase of osteopenia (from diagnosis) in bone radiology series. * Others: amyloidosis with current organic damage, recurrent bacterial infections (more than 2 events in 12 months), symptomatic hyperviscosity, presence of plasmacytomas. * Patients with current and active dental disorders (dental, jaw infection, bone exposed in the mouth, jaw osteonecrosis). * Patients developing jaw osteonecrosis or other serious adverse events due to treatment with any bisphosphonate . * Significant liver disease: * Bilirubin \> 3 g/dl. * ALT \> 2.5 x the upper limit of normal * AST \> 2.5 x the upper limit of normal * Patients who are currently in another clinical trial or receiving any investigational agent. * Pregnancy or nursing. * Parathyroid gland diseases. * Previous malignancy with a high risk of death or bone disease: breast cancer, prostate cancer or lung cancer, even if on complete response. * Active presence of neoplasms other than Multiple Myeloma