Patient With MMRR Treated With Belantamab Mafotidine on Monotherapy

Inclusion Criteria: 1. Written informed consent may be obtained from the patient or legally authorized representative according to local regulations (patients who have already died may also be included) 2. Histologically or cytologically confirmed diagnosis of MM as defined according to IMWG criteria of 2016 and: 1. patient has undergone stem cells transplantation or is considered ineligible for transplantation, and 2. patient has received at least four therapies 3. patient is refractory to an anti-CD38 antibody (ex., daratumumab) alone or in combination, and to an IMiD (ex., lenalidomide or pomalidomide), and to a proteasome inhibitor (ex. bortezomib, ixazomib or carfilzomib). 3. Male or female equal and/or upper 18 years (at baseline) 4. Performance Status at baseline by ECOG scale 0-2 5. Adequate organ system functions at baseline 6. Female patients: a female patient is elegible if she is not pregnant or breastfeeding and at least one of the following conditions applies: * She is/was not a woman of childbearing potential (WOCBP) OR * She is/was using an highly effective contrapcetive method during the treatment period and at least 9 months after the last dose and she agrees not to donate eggs (ova, oocytes) for the purpose of reproduction during this period. * Highly sensitive negative serum pregnancy test within 72 hours of therapy (C1D1) and agreed to use effective contraception during the treatment period and for the next 9 months after the last dose of the drug. Male patient: male patient were/are elegible if agreed to follow from the first dose until the last dose of treatment to allow clearance of any altered sperm: * abstaining from sperm donation PLUS * abstaing from heterosexual relationship in accordance with one's preferred and habitual lifestyle (long-term and persistent abstinent) and agreed/accepted to remain abstinent OR * agree/agreed to use contraption as described below: agree to use male condom even though they have/had succesfully vasectomy and female partner uses/used an additional highly effective contraceptive method. 7. All toxicities related to previous treatment (defined by National Cancer Institute- Common Toxicity Criteria for Adverse Events (NCI-CTCAE) were Grade 1 or less at t at the time of treatment initiation within compassionate use programs, except alopecia and neuropathy grade 2. Exclusion Criteria: * The patients are/were not elegible for compassionate use programs (NPP, EAP)