Cizutamig for refractory seropositive rheumatoid arthritis

An Open-label Study Evaluating the Safety and Preliminary Clinical Activity of Cizutamig in Patients With Refractory Seropositive Rheumatoid Arthritis

This trial tests whether cizutamig, a BCMAxCD3 T‑cell engager, is safe and can help adults with seropositive rheumatoid arthritis that has not responded to other treatments.

Quick facts

• Phase: Phase 1
• Study type: Interventional
• Enrollment: 28 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (Academic / other)
• Locations: 1 site (Wuhan, Hubei)
• Trial ID: NCT06946199 on ClinicalTrials.gov

What this trial studies

This is an open‑label Phase 1 trial that gives cizutamig to adults with refractory seropositive rheumatoid arthritis and follows them for 52 weeks after dosing. The primary focus is safety and tolerability, with collection of pharmacokinetic, pharmacodynamic, and immunogenicity data. Investigators will also record preliminary clinical activity to see if symptoms or biomarkers improve. Eligible participants must have moderately to severely active RA and prior inadequate response or intolerance to targeted synthetic or biologic DMARDs.

Who should consider this trial

Good fit: Adults 18–75 with adult‑onset, moderately to severely active seropositive RA (RF and/or ACPA positive) who have not responded to or tolerated tsDMARDs and/or bDMARDs are the intended participants.

Not a fit: Patients who are seronegative, have other concomitant autoimmune diseases, active infections, immunodeficiency, recent live vaccination, CNS disease, or recent malignancy are unlikely to be eligible or benefit from this approach.

Why it matters

Potential benefit: If successful, cizutamig could reduce disease‑causing antibody‑producing B cells and improve symptoms in patients with refractory seropositive RA.

How similar studies have performed: Cizutamig (BCMAxCD3) has shown safety and clinical activity in trials for relapsed/refractory multiple myeloma, but using a BCMA‑targeting T‑cell engager in seropositive RA is a novel application.

Eligibility criteria

Inclusion Criteria:

1. 18 to 75 years old at the time of signing the informed consent form
2. Diagnosis of adult-onset RA as defined by the 2010 ACR/EULAR classification criteria
3. Moderately to severely active RA.
4. Positive test results for RF and/or ACPA at Screening.

Inadequate treatment response defined as either lack of clinical benefit or intolerability to treatment with tsDMARD and/or bDMARD Exclusion Criteria:

1. Inadequate clinical laboratory parameters at Screening
2. Patients with active infection
3. Receipt of live vaccine within 4 weeks prior to Screening
4. Presence of any concomitant autoimmune disease
5. History of progressive multifocal leukoencephalopathy
6. History of primary immunodeficiency or a hereditary deficiency of the complement system
7. Central nervous system disease
8. Presence of 1 or more significant concurrent medical conditions per investigator judgment
9. Have a diagnosis or history of malignant disease within 5 years
10. Serious mental illness, alcohol or drug abuse, dementia, or any other condition that would impair the patient's ability to receive the planned treatment or to understand informed consent at the study site as determined by local practice

Where this trial is running

Wuhan, Hubei

• Wuhan Union Hospital — Wuhan, Hubei, China (Recruiting)

Study contacts

• Principal investigator: Qiubai Li, Professor — Union Hospital, Tongji Medical College, Huazhong University of Science and Technology
• Study coordinator: Qiubai Li, Professor

Conditions Rheumatoid Arthritis; cizutamig; rheumatoid arthritis