A Study of Belantamab Mafodotin in Combination With Nirogacestat and Pomalidomide in People With Multiple Myeloma That Has Not Responded to Treatment or Has Come Back After Treatment

Belantamab mafodotin will be administered via IV infusion in an outpatient setting on Day 1 of Cycles 1-3. Treatment with belantamab mafodotin will be given at an initial dose of 1.0 mg/kg. The study will have a 3+3 dose escalation design for belantamab mafodotin. Belantamab mafodotin dose levels are 1.0 mg/kg, 1.4 mg/kg, and 1.9 mg/kg

1:1 randomization between nirogacestat 100mg BID or 100 mg QD during the 4 day run-in period. Treatment with nirogacestat will be 100mg BID continuously during each cycle for all subjects.

After the 4-day run-in period, all patients will receive nirogacestat in combination with belantamab, mafodotin and pomalidomide. Pomalidomide was added for day 1-14 for cycle 1-3 and day 1-14 and day 21-35 for C4+.