PET imaging with radiolabeled CIT-013 in rheumatoid arthritis

PET-Based Imaging to Evaluate the Distribution of Radiolabeled CIT-013 in Patients With Inflammatory Mediated Immune Disease

PHASE2 · Citryll BV · NCT07147959

This will test whether PET scans using radiolabeled CIT-013 can show where the drug goes in people aged 60–85 with active rheumatoid arthritis.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment12 (estimated)
Ages60 Years to 85 Years
SexAll
SponsorCitryll BV (industry)
Locations1 site (Nijmegen)
Trial IDNCT07147959 on ClinicalTrials.gov

What this trial studies

This Phase 2 interventional trial administers CIT-013 labeled with zirconium-89 and uses PET-CT to visualize where the antibody distributes in the body of people with active RA. Eligible participants receive a single radiolabeled dose and undergo PET-CT imaging to measure tissue uptake, particularly in inflamed joints, rather than relying only on blood levels. The imaging data will characterize local drug exposure to inform whether CIT-013 reaches sites of NET-related inflammation. Prior clinical work found CIT-013 to be well tolerated and to reduce NET formation, supporting this imaging-focused approach.

Who should consider this trial

Good fit: Men and non-childbearing-potential women aged 60–85 with active RA who meet the trial's disease activity criteria and can provide informed consent are the intended participants.

Not a fit: People younger than 60 or older than 85, those without active joint inflammation, women of childbearing potential, or anyone who does not meet the RA activity or safety criteria are unlikely to benefit from this imaging-focused protocol.

Why it matters

Potential benefit: If successful, the imaging could show whether CIT-013 reaches inflamed joints, helping guide dosing and further development for RA.

How similar studies have performed: Unlabeled CIT-013 has shown safety and reduced NET formation in prior trials and radiolabeled antibody PET imaging has been used in other settings, but using [89Zr]CIT-013 for PET in RA is a novel, less-tested application.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Female (of non-childbearing potential) or male between 60-85 years of age (both inclusive).
* For male participants with female partners of child-bearing potential, an adequate form of contraception must be adhered to, and men must refrain from donating sperm, prior to entry into the trial and for a further 6 months after IP administration.
* Willing and able to provide written, informed consent.

Exclusion Criteria:

* Diagnosed with RA according to the 2010 classification criteria of the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) ≥ 6 months prior to screening (diagnosis based on medical records).

Participants in Cohort A (active RA) must furthermore meet the following criteria:

\- Disease Activity Score 28 (DAS28) C-Reactive Protein (CRP) (DAS28-CRP) ≥ 4.2 AND ≥ 1 Swollen Joint AND ≥ 1 Tender Joint prior to screening.

Where this trial is running

Nijmegen

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: RA

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.