Another Breakthrough in Autoimmune Diseases! Leadingpharm Supports CD3×CD19 Bispecific Antibody Phase I Study Presented at EULAR 2026

June 2026 – The European Alliance of Associations for Rheumatology (EULAR) 2026 Annual Congress was held in London, UK. The research results of A‑319, a CD3×CD19 bispecific T‑cell engager (TCE), in treating active systemic lupus erythematosus (SLE)—conducted by Tianmao Yuanhe, Union Hospital of Wuhan, Stanford University, and other institutions, with Leadingpharm serving as the CRO for full implementation—were presented as a poster at this international academic stage. This marks another important milestone for Leadingpharm in the field of autoimmune disease innovative drug clinical research.

Current Clinical Pain Points in SLE – A New Breakthrough Opportunity for Bispecific TCE
 

SLE is a complex autoimmune disease characterized by abnormal B‑cell activation, autoantibody production, and multi‑organ involvement. Although CD19‑targeted therapies (e.g., rituximab, CAR‑T) have shown some efficacy in recent years, they still have limitations:
 

• Rituximab only clears certain B‑cell subsets, has limited effect on plasma cells, and cannot effectively inhibit the type I interferon pathway.

• CD19‑CAR‑T is efficacious but requires lymphodepleting chemotherapy, carries high safety risks, and is costly, limiting widespread use.

A‑319, as a CD3×CD19 bispecific T‑cell engager, mobilizes endogenous T cells (including tissue‑resident T cells) to target and eliminate autoreactive B cells without the need for lymphodepletion, offering the potential to become an “off‑the‑shelf” alternative therapy.
 

Resetting the Pathogenic Pathway via a Novel Mechanism – A‑319 Demonstrates Excellent Long‑Term Therapeutic Value
 

As the CRO for this study, Leadingpharm was responsible for project management, medical writing, clinical monitoring, data management, and biostatistics throughout, ensuring the study was conducted in strict compliance with GCP and international standards at high quality. The study integrated serum testing, renal histopathology, and single‑cell RNA sequencing (scRNA‑seq) of over 300,000 cells, representing a translational medicine study that deeply combines mechanistic exploration with clinical evaluation.
 

The most important mechanistic finding was that A‑319 treatment achieved broad‑spectrum suppression of the type I interferon (Type I IFN) pathway—an effect observed in proliferating T cells and residual plasma cells, in a dose‑dependent manner.
 

This finding has significant clinical implications:

• Unlike rituximab, A‑319 intervenes in the core pathogenic pathway of SLE from a mechanistic perspective.

• Its effect is highly consistent with that of CD19 CAR‑T, validating that deep B‑cell depletion is key to interferon resetting.

• It provides a molecular‑level explanation for the differential efficacy of CD19‑targeted therapies.
   

52‑week follow‑up data showed that patients achieved progressive glucocorticoid tapering while experiencing clinical symptom improvement, with most patients reducing prednisone‑equivalent doses to below 10 mg/day, demonstrating favorable long‑term benefit trends.
 

Mechanistic Innovation Lays the Foundation – Novel Therapy Empowers the Future of Lupus Treatment
 

As the first CD3×CD19 bispecific TCE therapy to conduct clinical research in SLE, this Phase I study not only confirmed the safety and preliminary efficacy of this class of drugs in SLE but also, through deep single‑cell transcriptomic and immune repertoire analyses, revealed the core mechanism of “deep B‑cell depletion → type I interferon pathway reset,” providing a solid scientific basis for subsequent clinical development.
 

Leadingpharm demonstrated professional CRO capabilities in this autoimmune disease study: from complex biomarker‑integrated study design, to efficient multi‑center clinical trial execution, to in‑depth mining of translational data—fully embodying its service philosophy of “clinical value‑oriented and scientific innovation‑driven.”
 

Currently, an extension study of A‑319 subcutaneous formulation is ongoing. In the future, Leadingpharm will continue to work closely with partners, deepen its efforts in autoimmune diseases, and promote more innovative therapies from the lab to the clinic, bringing new hope to patients.
 

About Us

Deep Blue Ocean Biopharmaceutical is the clinical CRO sub‑brand of Leadingpharm (stock code 600222), established in 2007. Adhering to the philosophy “End‑to‑End, Top‑Level Design, Being the Full‑Process Partner for New Drug Development,” it provides global pharmaceutical companies with services covering Phase I‑III clinical studies, bioequivalence studies, third‑party auditing, IND application strategy guidance, and medical affairs for biologics, chemical drugs, TCM, medical devices, and cell & gene therapies. It meets the customized clinical research needs of various R&D‑oriented companies and helps clients overcome key bottlenecks before new drug launch.

To date, the company has conducted over 2,000 clinical research projects. In cell & gene therapy and aesthetic medicine, multiple projects have achieved domestic/international first‑in‑human or first‑approved status, filling gaps in China and globally. It also possesses extensive experience and resource accumulation in endocrinology, cardiovascular, oncology, rheumatology & immunology, pediatrics, rare diseases, and neuropsychiatry.
 

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