Used primarily in the treatment of multiple myeloma and mantle cell lymphoma, this compound functions as a proteasome inhibitor, disrupting the normal degradation of proteins in cancer cells. This disruption leads to an accumulation of abnormal proteins, triggering apoptosis, or programmed cell death, particularly in malignant cells that rely heavily on proteasome activity. It is especially effective in patients who have not responded to other therapies, including those who are relapsed or refractory. Administered intravenously or subcutaneously, it is often part of combination regimens with chemotherapy or corticosteroids to enhance efficacy. Its targeted mechanism offers a strategic advantage over traditional cytotoxic agents by focusing on the molecular machinery of cancer cells.