An Open-label Study of GB261 in Refractory Seropositive Systemic Lupus Erythematosus

The purpose of the study is to evaluate the safety and efficacy of CD20xCD3 T-cell engager (GB261) in patients with refractory seropositive systemic lupus erythematosus.

B cells play an important role in the pathogenesis of systemic lupus erythematosus (SLE). CD20 is a transmembrane receptor that is highly expressed on approximately 95% of B lineage cells. The use of anti-CD20 for B cell depletion represents a significant breakthrough in the treatment of B-cell-mediated autoimmune diseases. GB261 is a novel CD20/CD3 bispecific TCE that is designed to have very low affinity for CD3 and high affinity for CD20 to enable efficient T cell-mediated killing while minimizing risk of cytokine release syndrome (CRS). GB261 has shown promising safety and anti-tumor activity in a Phase 1/2 study in patients with relapsed/refractory B-cell non-Hodgkin lymphoma and chronic lymphocytic leukemia. GB261 offers a promising mechanism of action for SLE. This study aims to assess the safety, tolerability, PK, pharmacodynamics (PD), immunogenicity, and preliminary clinical activity of GB261 administered in patients with SLE. Patients will be invited to participate in the study, to receive GB261 intravenous infusion and monitored from the first dose of GB261 until Week 52.