Innovent Biologics Announces Pre-Clinical Results of IBI3055, A Tri-Specific T Cell Engager Targeting Autoimmune Diseases

Innovent Biologics, Inc. presented for the first time the preclinical data of IBI3055, a proprietary anti-CD19/BCMA/CD3 tri-specific T cell engager for the treatment of autoimmune diseases, as an oral presentation at the 2026 Immune Resetting: B-Cell Mediated & Beyond Summit in Boston, Massachusetts (USA). IBI3055 is a novel tri-specific antibody targeting CD19, B-cell maturation antigen (BCMA), and CD3. It is built on an innovative "1+1+1" T-cell engager format and incorporates steric hindrance-based CD3 masking to reduce non-specific T-cell activation, aiming to achieve an optimal balance between potent immune cell depletion and favorable safety profile.

IBI3055 is intended for the treatment of various B cell- or plasma cell-mediated autoimmune diseases. IBI3055 employs a unique "1+1+1" design with CD3 masking, enabling target-dependent T cell activation and potentially improving safety and pharmacokinetic properties. IBI3055 demonstrates effective cytotoxicity against either CD19- or BCMA-positive cells across varying expression levels, with potency comparable to corresponding mono-targeting T cell engagers.

In human CD19/BCMA/CD3 transgenic mouse models, IBI3055 induces deep depletion of B cells and plasma cells in peripheral blood, spleen, lymph nodes, and bone marrow, along with significant reductions in circulating immunoglobulin levels, showing greater activity than mono-targeting CD19 or BCMA T-cell engagers. In non-human primates, IBI3055 also achieves profound depletion of B cells and plasma cells across multiple compartments and significantly reduces circulating immunoglobulins, while demonstrating favorable safety and tolerability. IBI3055 is an internally developed tri-specific antibody targeting CD19, BCMA, and CD3, featuring an innovative "1+1+1" T-cell engager design with CD3 masking to minimize non-specific T-cell activation.

Preclinical studies show that IBI3055 effectively eliminates CD19- or BCMA-positive cells across a range of expression levels, with activity comparable to mono-targeting T cell engagers. It induces deep depletion of B cells and plasma cells and significantly reduces immunoglobulin levels in multiple in vivo models, while demonstrating favorable tolerability, highlighting its potential in treating B cell- or plasma cell-mediated autoimmune diseases.