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