M3258 + dexamethasone

M3258 + dexamethasone is a combination therapy studied for relapsed or refractory multiple myeloma. M3258 is an orally bioavailable, potent, reversible, and highly selective inhibitor of the immunoproteasome subunit LMP7 (also known as β5i or PSMB8), which is highly expressed in malignant hematolymphoid cells such as multiple myeloma. Inhibition of LMP7 disrupts protein degradation and induces apoptosis in target cells. Dexamethasone is a synthetic glucocorticoid with anti-inflammatory and anti-proliferative effects, commonly used in combination therapies for hematological malignancies. The combination was evaluated in a Phase 1 clinical trial, but development was terminated at this stage[1][5][7].