FAPI PET/CT to find tiny remaining IgG4‑RD lesions and guide treatment

A Prospective Study on the Effect of Minimal Residual Disease Detected by Fibroblast Activation Protein PET / CT on the Recurrence of IgG4-related Disease

This trial will test whether a new 68Ga‑FAPI PET/CT scan can find tiny leftover disease and help decide whether adults with IgG4‑related disease in clinical remission need ongoing treatment.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 46 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: Peking Union Medical College Hospital (Academic / other)
• Drugs / interventions: methotrexate, prednisone
• Locations: 1 site (Beijing, Beijing Municipality)
• Trial ID: NCT07104058 on ClinicalTrials.gov

What this trial studies

This is a prospective randomized study enrolling adults with IgG4‑RD who have been in clinical complete remission for at least one year and have negative 18F‑FDG PET/CT after therapy. All participants receive a 68Ga‑FAPI PET/CT scan and are stratified as MRD‑negative (FAPI‑) or MRD‑positive (FAPI+). MRD‑negative patients stop treatment and are observed, while MRD‑positive patients are randomized to either low‑dose glucocorticoid ± immunosuppressant maintenance or treatment withdrawal, with only endpoint assessors blinded. Participants are followed for 18 months with quarterly clinical assessments to document relapse rates.

Who should consider this trial

Good fit: Adults 18–75 with confirmed IgG4‑RD who have been clinically in complete remission for ≥1 year and have negative 18F‑FDG PET/CT while on low‑dose prednisone (≤7.5 mg/day) or stable immunosuppressant doses are ideal candidates.

Not a fit: Patients with active disease, other connective tissue diseases, malignancy, pregnancy/planning pregnancy, active infections, severe irreversible organ damage, or recent relapse are unlikely to benefit and are excluded.

Why it matters

Potential benefit: If successful, this could let doctors detect hidden residual disease and tailor maintenance therapy to reduce relapses.

How similar studies have performed: FAPI PET/CT is an emerging imaging tool that has shown promise in detecting fibrotic or inflammatory lesions in other conditions, but using it to predict relapse in IgG4‑RD is novel and not yet proven.

Eligibility criteria

Inclusion Criteria:

1. age 18-75 years old ;
2. Meet the 2019 ACR / EURLAR IgG4-RD diagnostic criteria ;
3. The disease was stable for more than 1 year, and the clinical evaluation of the disease was complete remission \* ;
4. Glucocorticoid dosage ≤ prednisone 7.5mg / d × 6 months or more, or combined with an immunosuppressive therapy ( mycophenolate mofetil ) Ester ≤ 1.0g / d, leflunomide ≤ 20mg / d, methotrexate ≤ 15mg / w, azathioprine ≤ 100mg / d, iguratimod ≤ 25mg Bid )

Exclusion Criteria:

( 1 ) Combined with other connective tissue disease patients ( 2 ) patients with tumor ; ( 3 ) women during pregnancy or planning pregnancy ; ( 4 ) active infection, including HIV, HCV, HBV, TB, etc. ; ( 5 ) Severe irreversible organ damage ; ( 6 ) In the active stage of the disease, the IgG4-RD reaction index score of the single affected organ was 2 points ; ( 7 ) stable condition less than 1 year ; ( 8 ) patients who relapsed within 1 year of previous hormone reduction and withdrawal ; ( 9 ) Combination of two or more immunosuppressive agents.

Where this trial is running

Beijing, Beijing Municipality

• Peking Union Medical College Hospital — Beijing, Beijing Municipality, China (Recruiting)

Study contacts

• Principal investigator: Yaping LUO, MD — Peking Union Medical College Hospital
• Study coordinator: Yaping Luo, MD

Conditions IgG4-Related Diseases; FAPI PET/CT