Study to Investigate Alternative Dosing Regimens of Belantamab Mafodotin in Participants With Relapsed or Refractory Multiple Myeloma

Inclusion Criteria: * Participant must be 18 years of age inclusive at the time of signing the informed consent form (ICF). * Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. * Histologically or cytologically confirmed diagnosis of MM and a. Has undergone stem cell transplant or is considered transplant ineligible, and b. Has failed at least 3 prior lines of anti-myeloma therapies, including an anti-cluster of differentiation (CD)38 antibody (e.g., daratumumab) alone or in combination and is refractory to an immunomodulatory agent (e.g., lenalidomide, pomalidomide) and a proteasome inhibitor (e.g., bortezomib, ixazomib, carfilzomib). * France specific: participants have failed at least 4 prior lines of anti-myeloma therapies * Participant has measurable disease per modified IMWG criteria. * Life expectancy of at least 6 months, in the opinion of the investigator. * Male and female participants agree to abide by protocol-defined contraceptive requirements. * Participant is capable of giving signed informed consent. * Participant meets country-specific inclusion criteria described in the protocol. Exclusion Criteria: * Symptomatic amyloidosis, active POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, myeloma protein, and skin changes), or active plasma cell leukemia at the time of screening. * Current corneal epithelial disease, except nonconfluent superficial punctate keratitis (SPK). * Evidence of active mucosal or internal bleeding. * Pre…