Skip to main content
An official website of the United States government
Government Funding Lapse
Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.

Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

anti-PD-1/anti-4-1BB bispecific antibody IBI-319

A bispecific antibody targeting both the human negative immunoregulatory checkpoint receptor programmed cell death protein 1 (PD-1; PDCD1; CD279) and 4-1BB (CD137; tumor necrosis factor receptor superfamily member 9; TNFRSF9), with potential checkpoint inhibitory, immunostimulating and antineoplastic activities. Upon administration, anti-PD-1/anti-4-1BB bispecific antibody IBI-319 simultaneously targets and binds to PD-1, which is expressed on a variety of leukocyte subsets including activated T lymphocytes in the tumor microenvironment (TME), and 4-1BB, which is expressed on activated T lymphocytes and natural killer (NK) cells. This crosslinks PD-1- and 4-1BB-expressing T cells. Through 4-1BB binding, IBI-319 acts as a conditional 4-1BB agonist, resulting in T-cell co-stimulation and enhances T-lymphocyte-mediated anti-tumor activity. At the same time, PD-1 binding prevents PD-L1 from binding to and activating its receptor PD-1 and inhibits the PD-L1/PD-1-mediated downregulation of T-cell activation and proliferation. This abrogates T-cell inhibition, activates antigen-specific T lymphocytes and enhances cytotoxic T-cell-mediated tumor cell lysis, which may lead to a reduction in tumor growth. PD-L1 binding to PD-1 on activated T cells inhibits the expansion and survival of CD8-positive T cells, suppresses the immune system and results in immune evasion. 4-1BB, a surface glycoprotein of the tumor necrosis factor receptor superfamily, is an inducible costimulatory receptor that plays a key role in T-cell proliferation, survival and cytolytic activity.
Code name:IBI 319
IBI-319
IBI319
Search NCI's Drug Dictionary