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Antibody and Fusion Proteins

Antibodies are proteins involved in the immune system’s response to attacks, such as infections. Antibodies play a central role in autoimmune diseases in which the body mistakenly launches immune system attacks on itself with antibodies, making them a target molecule for drug developers. However, using a single antibody-based drug as an autoimmune therapeutic is sometimes not enough, bringing efficacy or even safety concerns. But by taking specific parts from multiple antibodies, a fusion antibody has the desired properties from each of the proteins it contains.

 

RC18: A TACI-Fc Fusion Antibody

Investigational candidate RC18 is a fusion antibody created by RemeGen scientists to target signaling factors involved in the development and survival of B cells, the cell responsible for generating antibodies. RC18 is a fusion of a TACI (transmembrane activator and calcium modulator and cyclophilin ligand interactors) protein and the IgG protein.

TACI Protein

  • • Lives on the surface of B cells
  • • Binds to cell-signaling molecules BLyS and APRIL
  • • Trigger immune response

IgG Protein

  • • Most common antibody in the human body
  • • Helps increase the stability of the fusion protein

RC18 binds to BLyS (B lymphocyte stimulator) and APRIL (a proliferation-inducing ligand), preventing these cell-signaling molecules from binding to TACI proteins on the surface of the B cell. This inhibits the development and survival of mature B cells, preventing the formation of autoantibodies. We believe RC18 has the potential to interrupt autoimmune responses, such as those in conditions like systemic lupus erythematosus (SLE).

After successful Phase 2 studies in SLE, we are developing a strategic Phase 3 clinical study plan to avoid the known pitfalls in the historical SLE study landscape. Based on early data, RemeGen is hopeful that RC18 will continue to be a promising potential new treatment option for SLE. RemeGen is also studying RC18 in rheumatoid arthritis, neuromyelitis optica spectrum disorder, multiple sclerosis, IgA nephritis, gravis and Sjogren’s syndrome.

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