A Phase III, Multicenter, Open-Label, Randomized Study to Evaluate the Efficacy and Safety of Belantamab Mafodotin in Combination With Pomalidomide and Dexamethasone (B-Pd) Versus Pomalidomide Plus Bortezomib and Dexamethasone (PVd) in Participants With Relapsed/Refractory Multiple Myeloma (DREAMM 8)

• 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 International Myeloma Working Group (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;

• Urine M-protein excretion greater than or equal to (≥)200 milligrams (mg) per 24-hour, or

• Serum M-protein concentration ≥0.5 grams/deciliters (g/dL) (≥5.0 g/liter [L]), or

• Serum free light chain (FLC) assay: involved FLC level ≥10 mg/dL (≥100 mg/L) and an abnormal serum free light chain ratio (less than [<]0.26 or greater than [>]1.65) only if participant has no measurable urine or serum M spike.

• Have undergone autologous stem cell transplant (ASCT) or are considered transplant ineligible. Participants with a history of ASCT are eligible for study participation provided the following eligibility criteria are met: a. ASCT was >100 days prior to the first dose of study medication. b. No active bacterial, viral, or fungal infection(s) present

• All prior treatment-related toxicities (defined by National Cancer Institute Common Terminology Criteria for Adverse Events [NCI-CTCAE] version 5.0) must be less than or equal to (≤)Grade 1 at the time of enrolment, except for alopecia.

• Adequate organ system functions as mentioned in the protocol.

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