The study aims to evaluate the efficacy and safety of belantamab mafodotin in combination with cyclophosphamide, bortezomib, and dexamethasone in adult participants with newly diagnosed (ND) AL amyloidosis .

The goal of this study is to test the safety of drug, Belantamab Mafodotin, and see what effects (good and bad) it has on people who take it and have amyloidosis, and to determine the most effective dose of the drug.

The study will have 2 phases (parts). The first phase of the study will test different doses of Belantamab Mafodotin. The second phase will test Belantamab Mafodotin at the dose level found to be safe and effective in phase 1