Inclusion Criteria:

          -  Capable of giving signed informed consent.

          -  Male or female, 18 years or older.

          -  Have a confirmed diagnosis of multiple myeloma (MM) as defined by the IMWG criteria.

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2.

          -  Have been previously treated with at least 1 prior line of MM therapy including a
             lenalidomide-containing regimen and must have documented disease progression during or
             after their most recent therapy.

          -  Must have at least 1 aspect of measurable disease defined as one of the following;

               1. Urine M-protein excretion >=200 mg per 24-hour, or

               2. Serum M-protein concentration >=0.5 grams per deciliter, or

               3. Serum free light chain (FLC) assay: involved FLC level >=10 mg per deciliter and
                  an abnormal serum free light chain ratio (<0.26 or >1.65) only if participant has
                  no measurable urine or serum M spike.

          -  Have undergone autologous stem cell transplant (SCT) or are considered transplant
             ineligible. Participants with a history of autologous SCT may be eligible for study
             participation.

          -  All prior treatment-related toxicities (defined by National Cancer Institute Common
             Toxicity Criteria for Adverse Events [NCI-CTCAE] version 5.0) must be <=Grade 1 at the
             time of enrolment, except for alopecia.

          -  Adequate organ system functions.

          -  Male and female participants agree to abide by protocol-defined contraceptive
             requirements.

        Exclusion Criteria:

          -  Active plasma cell leukemia, symptomatic amyloidosis or active polyneuropathy,
             organomegaly, endocrinopathy, monoclonal plasma proliferative disorder, and skin
             changes (POEMS) syndrome at the time of screening.

          -  Prior allogeneic SCT.

          -  Systemic anti-myeloma therapy (including chemotherapy and systemic steroids) within 14
             days or five half-lives (whichever is shorter) preceding the first dose of study drug;
             prior treatment with a monoclonal antibody drug within 30 days of receiving the first
             dose of study drugs.

          -  Plasmapheresis within 7 days prior to the first dose of study drug.

          -  Received prior treatment with or intolerant to pomalidomide.

          -  Received prior Beta cell maturation antigen (BCMA) targeted therapy.

          -  Intolerant to bortezomib or refractory to bortezomib (for example; participant
             experienced progressive disease during treatment, or within 60 days of completing
             treatment, with a bortezomib-containing regimen of 1.3 mg/ m^2 twice weekly).

          -  Evidence of cardiovascular risk including any of the following;

               1. Evidence of current clinically significant untreated arrhythmias, including
                  clinically significant electrocardiogram abnormalities including second degree
                  (Mobitz type II) or third degree atrioventricular (AV) block.

               2. Recent history within (3 months of screening) of myocardial infarction, acute
                  coronary syndromes (including unstable angina), coronary angioplasty, or stenting
                  or bypass grafting .

               3. Class III or IV heart failure as defined by the New York Heart Association
                  functional classification system

               4. Uncontrolled hypertension.

          -  Any major surgery within the last 4 weeks.

          -  Previous or concurrent invasive malignancy other than multiple myeloma, except:

               1. The disease must be considered medically stable for at least 2 years; or

               2. The participant must not be receiving active therapy, other than hormonal therapy
                  for this disease.

          -  Known immediate or delayed hypersensitivity reaction or idiosyncratic reaction to
             belantamab mafodotin or drugs chemically related to belantamab mafodotin, or any of
             the components of the study treatment.

          -  Evidence of active mucosal or internal bleeding.

          -  Cirrhosis or current unstable liver or biliary disease per investigator assessment
             defined by the presence of ascites, encephalopathy, coagulopathy, hypoalbuminaemia,
             oesophageal or gastric varices, persistent jaundice.

          -  Active infection requiring treatment.

          -  Known human immunodeficiency virus (HIV) infection.

          -  Presence of hepatitis B surface antigen (HbsAg), or hepatitis B core antibody (HbcAb)
             at screening or within 3 months prior to first dose of study treatment.

          -  Positive hepatitis C antibody test result or positive hepatitis ribonucleic acid test
             result at screening or within 3 months prior to first dose of study treatment.

          -  Intolerance or contraindications to anti-viral prophylaxis.

          -  Presence of active renal conditions (such as infection, severe renal impairment
             requiring dialysis or any other condition that could affect participant's safety).

          -  Ongoing Grade 2 or higher peripheral neuropathy or neuropathic pain.

          -  Active or history of venous thromboembolism within the past 3 months.

          -  Contraindications to or unwilling to undergo protocol-required anti-thrombotic
             prophylaxis.

          -  Current corneal disease except for mild punctate keratopathy.

          -  Any serious and/or unstable pre-existing medical, psychiatric disorder or other
             conditions (including lab abnormalities) that could interfere with participant's
             safety, obtaining informed consent or compliance to the study procedures.

          -  Pregnant or lactating female.