Inclusion Criteria:

- Understand and voluntarily sign an informed consent form.

- Age 18 years at the time of signing the informed consent form.

- Life expectancy of at least 3 months

- Able to adhere to the study visit schedule and other protocol requirements

- Relapsed or refractory active MM (according to the International Myeloma Working
Group guidelines) after treatments containing bortezomib and lenalidomide or
ineligible (intolerance or toxicity) to one of these drugs with detectable myeloma
protein in blood or urine.

- Disease free of prior malignancies for at least 5 years.

- All previous multiple myeloma treatments, including radiation, cytostatic therapy and
surgery, must have been discontinued at least 4 weeks prior to treatment in this
study, except corticosteroids therapy.

- ECOG performance status <2 at study entry, unless it is due to MM.

- At least the following laboratory findings at the day of treatment start:

- Platelet count ≥ 75 x 10^9/L without transfusional support within 7 days.

- Neutrophil count > 1.5 x 10^9/L without G-CSF.

- Corrected calcium ≤ 14 mg/dL (3.5 mmol/L).

- AST: ≤ 2.5 times the normal upper limit.

- ALT: ≤ 2.5 times the normal upper limit.

- Total bilirubin: ≤ 1.5 times the normal upper limit.

- Measured or calculated creatinine clearance of ≥ 20 mL/minute

- Women of child bearing potential and male patients whose partner is a woman of child
bearing potential must be prepared to use two effective methods of contraception both
before and during protocol treatment, or commit to absolute and continuous
abstinence.The pregnancy test must be negative 14-28 days and 72 hours before
treatment start. Only in case of hysterectomy or presence of menopause for at least
24 consecutive months pregnancy tests as well as contraception are not necessary. Men
must not father a child for up to 6 months following cessation of treatment and must
use condoms.

Exclusion Criteria:

- Any serious medical condition, laboratory abnormality, or psychiatric illness that
would prevent the subject from signing the informed consent form.

- Pregnant or breast feeding females.

- Any condition, including the presence of laboratory abnormalities, which places the
subject at unacceptable risk if he/she were to participate in the study or confounds
the ability to interpret data from the study.

- Patients with contraindications for treatment with bendamustine, dexamethasone and
thalidomide.

- Uncontrolled or severe cardiovascular disease, including myocardial infarction within
6 months before study entry, New York Heart Association Class III or IV heart
failure, uncontrolled angina or severe uncontrolled ventricular arrhythmias (≥ Lown
3).

- Use of any other experimental drug or therapy within 28 days of baseline.

- Known hypersensitivity to thalidomide or purine analogues

- Concurrent use of other anti-cancer agents or treatments other stated in this
treatment plan.

- Peripheral neuropathy grade ≥2 according to WHO

- Known positive for HIV or infectious hepatitis, type A, B or C.

- Major surgery less than 30 days before start of treatment