A Study to Investigate Safety and Clinical Activity of Belantamab Mafodotin in Combination With Lenalidomide, Dexamethasone and Nirogacestat in Patients With Transplant Ineligible Newly Diagnosed Multiple Myeloma

This is a phase 1/2, open-label study designed to assess the safety and clinical activity of different belantamab mafodotin doses in combination with lenalidomide, dexamethasone and nirogacestat in patients with transplant ineligible newly diagnosed multiple myeloma. This will be a 2-part study. In part 1 participants will be enrolled in one cohort to receive belantamab mafodotin in combination with lenalidomide, dexamethasone and nirogacestat and will determine the recommended phase 2 dose (RP2D) to be further evaluated for safety and clinical activity in the dose expansion cohort. The RP2D dose will be used in future studies in the transplant-ineligible newly diagnosed multiple myeloma (NDMM) setting. In the dose expansion phase (Part 2) an expansion cohort will be treated with the RP2D. The expansion cohort will randomize participants (1:1) in two groups to evaluate two alternate dose modification guidelines for corneal AEs. Part 2 of the study will also evaluate an alternative dose modification guideline for corneal adverse events (AEs). Overall, approximately 36 participants will be enrolled in the study. Participant follow-up will continue up to 3 years after the last participant is enrolled (follow-up period range: 3-4 years). The estimated accrual period will be 12 months, corresponding to an approximate total study duration of 4 years.