Acasunlimab is a recombinant Fc-silenced IgG1 bispecific antibody targeting PD-L1 and 4-1BB, with checkpoint inhibitory, immunostimulating, and antineoplastic activities. It enhances antitumor immune response by enabling conditional 4-1BB activation strictly dependent on PD-L1 binding. M.W 144.3 kDa