MM cells harboring t(14;16) are resistant to PIs in vitroand are associated with a poor prognosis in MM patients. PFS (A) and OS (B) according to MAF expression status in patients in the TT3 clinical study. APR1 (C,E) and H929 (D,F) and were seeded at 2 × 10⁴ per well in 96-well plates and cultured in growth media in the presence of the indicated concentrations of Bzb (C-D) or CFZ (E-F) for 24 and 48 hours. Proliferation was measured by MTT assay. Results are presented as mean ± standard error (SE) (n = 4). Data are representative of 3 separate experiments. MM cells lines were treated with serial concentrations of Bzb (G) and CFZ (H) for 48 hours and proliferation was measured by MTT assay. The IC₅₀ of Bzb (G) and CFZ (H) were classified based on molecular subgroups.