Modakafusp alfa immunocytokine fusion protein. Novel immune mechanisms of action. Modakafusp alfa immunocytokine-induced myeloma cell death by delivering interferon alfa signaling to CD38⁺ myeloma tumor cells and enhancing immune activation by signaling to immune cells carrying CD38⁺ and interferon alfa receptors. IFN, interferon; IFNa2bR, interferon alfa-2b receptor; mAb, monoclonal antibody.