ALPN-303

A dual B cell cytokine antagonist of BAFF and APRIL with best-in-class potential

ALPN-303 is a dual B cell cytokine antagonist being developed for B cell-mediated autoimmune/inflammatory diseases. Engineered using our proprietary directed evolution platform, ALPN-303 is an Fc fusion protein of a human transmembrane activator and CAML interactor (TACI) variant TNFR domain (vTD) inhibiting the pleiotropic B cell cytokines B cell activating factor (BAFF) and a proliferation inducing ligand (APRIL). BAFF and APRIL are tumor necrosis factor (TNF) superfamily cytokines which play key roles in B cell development, differentiation, and survival, contributing to the pathogenesis of B cell-related autoimmune diseases like systemic lupus erythematosus (SLE), Sjögren’s syndrome, inflammatory arthritis, multiple sclerosis, and many others. By simultaneously blocking these two TNF superfamily members, ALPN-303 has the potential to improve outcomes in patients suffering from severe autoimmune/inflammatory disease.

The best-in-class potential of ALPN-303 is supported by research presented at the 2020 EULAR Virtual Congress demonstrating TACI vTDs:

• Appears more potent than existing BAFF and APRIL inhibitors in vitro and in vivo
• In models of lupus and Sjögren’s syndrome, reduce key markers of renal disease and sialoadenitis relative to controls

Details of our published research can be found here.