DREAMM 14: This phase II study is evaluating alternative dosing regimens of immunotherapy (belantamab mafodotin) in people with relapsed or refractory multiple myeloma to determine if this improves outcomes and reduces side effects.A Phase 2, Randomized, Parallel, Open-label Study to Investigate the Safety, Efficacy, and Pharmacokinetics of Various Dosing Regimens of Single-agent Belantamab Mafodotin (GSK2857916) in Participants With Relapsed or Refractory Multiple Myeloma (DREAMM-14)

Exclusion

• 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.
• Presence of an active renal condition.
• Any serious and/or unstable pre-existing medical condition, psychiatric disorder, or other conditions that could interfere with the participant's safety, obtaining informed consent, or compliance with the study procedures.
• Malignancies other than the disease under study, except for any other malignancy from which the participant has been disease free for >2 years and, will not affect the evaluation of the effects of the study treatment on the currently targeted malignancy (MM). Participants with curatively treated non-melanoma skin cancer may be enrolled without a 2-year restriction.
• Evidence of cardiovascular risk as per the protocol criteria.
• Pregnant or lactating female.
• Active infection requiring antibiotic, antiviral, or antifungal treatment.
• Known human immunodeficiency virus (HIV) infection, unless the criteria in protocol can be met.
• Hepatitis B and C will be excluded unless the criteria in protocol can be met.
• Cirrhosis or current unstable liver or biliary disease.
• Alanine aminotransferase (ALT) >2.5× upper limit of normal (ULN).
• Total Bilirubin >1.5×ULN.
• Systemic anti-MM therapy within <=14 days or 5 half-lives, whichever is shorter.
• Systemic therapy with high dose steroids within <=14 days before the first dose of study treatment.
• Prior allogenic stem cell transplant.
• Prior treatment with a monoclonal antibody <=30 days before the first dose of study treatment. Use of monoclonal antibodies for serious conditions unrelated to multiple myeloma, such as COVID, may be permitted.
• Prior treatment with an anti-B cell maturation antigen (BCMA) targeted therapy or hypersensitivity reactions to any components of the study treatment.
• Treatment with an antibody-drug conjugate.
• Participant has received any major surgery <=4 weeks before the first dose of study treatment. An exception may be allowed for bone stabilizing surgery.
• Inadequate bone marrow reserve or organ functions as demonstrated by any of the following: a. Absolute neutrophil count <1.0×10^9/L, b. Hemoglobin <8 gram/deciliter (g/dL), c. Platelet count <50×10^9/L, d. Spot urine (albumin/creatinine ratio) >500 milligram/gram (mg/g), e. Estimated glomerular filtration rate (eGFR) <30 milliliter per minute per 1.73 meter square (mL/min/1.73m^2).
• UK specific: a. Absolute neutrophil count <1.5×10^9/L, c. Platelet count <75×10^9/L