mRNA (ABO2203) that delivers a CD19/CD3 T‑cell engager for people with refractory autoimmune diseases

A Clinical Study to Investigate Safety, Tolerability, and Preliminary Efficacy of mRNA Encoding CD19/CD3 T Cell Engager (ABO2203) in Patients With Refractory Autoimmune Diseases

This trial will test whether an mRNA injection called ABO2203, which produces a CD19/CD3 T‑cell engager, is safe and helpful for adults whose autoimmune disease did not respond to standard treatments.

Quick facts

• Phase: Early Phase 1
• Study type: Interventional
• Enrollment: 66 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Ruijin Hospital (Academic / other)
• Locations: 3 sites (Wuhan, Hubei and 2 other locations)
• Trial ID: NCT06747156 on ClinicalTrials.gov

What this trial studies

This early phase 1 program gives escalating doses of ABO2203, an mRNA formulation that encodes a CD19/CD3 T‑cell engager, by injection to adults with autoimmune diseases who had inadequate response or relapse after standard therapies. The design includes a dose‑escalation portion to find a tolerable dose and a dose‑expansion portion to gather additional safety and early activity data. Key outcomes collected include safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy signals. Participants must meet disease‑specific diagnostic criteria, be on a stable background therapy, and have adequate organ function.

Who should consider this trial

Good fit: Adults (≥18) with a diagnosed autoimmune disease who relapsed or did not respond to standard of care, are on a stable dose of background therapy, and have sufficient organ function would be typical candidates.

Not a fit: Patients with active infections, severe hypogammaglobulinemia or liver/cardiac dysfunction, recent cancers, uncontrolled allergic conditions, or recent B‑cell/biologic therapies per protocol are unlikely to benefit or would be excluded.

Why it matters

Potential benefit: If successful, ABO2203 could become a new treatment option for patients whose autoimmune conditions have not responded to standard therapies by temporarily directing T cells to target B cells.

How similar studies have performed: CD19‑targeting approaches such as B‑cell depleting antibodies and CAR‑T therapies have benefited some autoimmune patients, but delivering a CD19/CD3 engager via mRNA is a newer strategy with limited prior clinical data.

Eligibility criteria

Inclusion Criteria:

1. ≥18 years of age at time of informed consent.
2. Diagnosis of autoimmune diseases according to the corresponding disease classification criteria.
3. Inadequate response to SoCs or relapsed after the treatment.
4. Patients were on a stable dose of SoCs for at least 4 weeks prior to enrollment.
5. Sufficient organ function.

Exclusion Criteria:

1. Active infection, including tuberculosis, active or relapsed peptic ulcer, etc.
2. Severe hypogammaglobulinemia or IgA deficiency.
3. Active hepatitis or with a history of severe liver disease.
4. History of rapid allergic reactions, eczema or asthma that cannot be controlled by topical corticosteroids.
5. Severe cardiovascular diseases.
6. History of cancer within past 5 years.
7. Have other serious medical conditions.
8. Received any of B cell targeted therapies and biologic therapies within the defined time window.
9. History of severe allergies or known allergies to any active or inactive component of the study drug(s).
10. A history of organ transplantation, bone marrow transplantation or hematopoietic stem cell transplantation.

Where this trial is running

Wuhan, Hubei and 2 other locations

• Union Hospital, Tongji Medical College, Huazhong University of Science and Technology — Wuhan, Hubei, China (Not_yet_recruiting)
• Nanjing Drum Tower Hospital — Nanjing, Jiangsu, China (Recruiting)
• Ruijin Hospital — Shanghai, China (Recruiting)

Study contacts

• Principal investigator: Chengde Yang — Ruijin Hospital
• Study coordinator: Qiongyi Hu

Conditions Autoimmune Diseases