CD79 is a crucial component of the B-cell receptor (BCR) complex, composed of two distinct polypeptide chains known as CD79a (Igα) and CD79b (Igβ). These two chains form a heterodimer on the surface of B cells via disulfide bonds and, together with membrane-bound immunoglobulin (mIg), constitute the BCR complex.

CD79a/CD79b-Mediated BCR Signaling PathwayThrough extensive signaling networks, it activates various downstream signaling molecules, including Syk, thereby initiating signaling pathways such as PI3K, BTK, and NF-κB. This regulates B cell activation, proliferation, differentiation, and antibody production, playing a central role in maintaining normal B cell homeostasis and promoting the abnormal survival of malignant B cells.^[2]

CD79b is predominantly expressed from the pre-B cell stage through to mature B cells, is abundantly expressed in lymphoid tissues such as lymph nodes and the spleen, and serves as a key molecule in BCR signaling.[3]

In various B-cell lymphomas, CD79b also exhibits high expression, making it aTreatment of B-cell Lymphomaone of the important targets. For instance, in certain B-cell lymphomas, CD79b may constitutively activate downstream signaling pathways due to genetic mutations or aberrant expression, leading to abnormal proliferation and survival of B cells, thereby providing a growth advantage to lymphoma cells and enabling them to evade normal apoptotic mechanisms.

In immunological research, the role of CD79b is not limited to signal transduction but may also involveCell Activation, Proliferation, and Cell Deathmodulation, making it a potential therapeutic target. For instance, therapies targeting CD79B have been explored for their effects on autoimmune diseases such as systemic lupus erythematosus and have shown promise in B cell–related treatment strategies.

Only One CD79b ADC Is Marketed GloballyPolatuzumab vedotin, developed by Roche/Genentech, has been approved for indications including diffuse large B-cell lymphoma (DLBCL). In China, the drug was approved for marketing by the NMPA in January 2023 (Polivy® polatuzumab vedotin), thereby validating the clinical value of the CD79b target.

Currently, CD79b drug development hasExtending from a "single ADC" to diversified technology platforms such as TCEs, multispecific antibodies, and autologous CAR-T, the key global drug development projects are shown in the figure below:

ADCs remain the primary focus of CD79b development, with multiple candidate drugs advancing to various clinical stages globally.

April 2025,Hengrui Medicine's SHR-A1912Registered the first Phase III clinical study for the treatment of DLBCL on the Drug Clinical Trial Registration and Information Publicity Platform, becoming the first domestically produced CD79b ADC to enter the Phase III clinical stage, thereby joining the first tier of innovative CD79b drug development.

As ADC therapies continue to mature, next-generation products are placing greater emphasis onSynergistic Mechanisms of Combined Targeted Therapy and ImmunotherapyFor example,PRV-3279is a humanized bispecific antibody targeting the B-cell surface proteins CD32B and CD79B, with the potential to treat B-cell-mediated autoimmune diseases and prevent or reduce the immunogenicity of biologic therapies.

It is worth mentioning that,CD19/CD79b Dual-Target CAR-TSuch strategies also reflect the R&D trend of enhancing treatment durability through dual-antigen coverage.

From the perspective of indications, companies have already made strategic moves.ARC-02, LTZ-301, and PRV-3279These products target autoimmune diseases such as systemic lupus erythematosus (SLE), continuously expanding the therapeutic landscape of this target.

CD79b R&D has gradually evolved from being dominated by early ADCs to a stage of parallel development across multiple technological platforms, including ADCs, bispecific antibodies, T-cell engagers (TCEs), and cell therapies.

As the development of CD79b-based combination therapies and the expansion into indications such as immunology continue to advance, CD79b is poised to further unlock its clinical potential in B-cell malignancies and autoimmune diseases.