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Not yet recruitingNCT07793903Updated Aug 31, 2026

BCT301 in Treating Refractory/Recurrent IgG4-related Disease

An interventional study of BCT301 Cell Injection in IgG4-related Disease, sponsored by Peking University Third Hospital. Not yet recruiting. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-08-31.

Sponsored by Peking University Third Hospital · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
6
Allocation
Not applicable
Ages
18 Years to 75 Years
Sex
All
01

Study summary

This is an investigator initiated trial to assess the safety and efficacy of BCT301 cell Injection (CAR-iT cells derived from chemically induced pluripotent stem cells) in patients with refractory/recurrent IgG4-related disease.

Read the detailed description

This is a single-arm, open-label, single-center clinical study in which all patients receive a unified treatment regimen. The primary objective is to evaluate the safety and tolerability of BCT301 Cell Injection in patients with refractory/recurrent IgG4-RD. Secondary objective is to evaluate the improvement in disease activity in patients with refractory/recurrent IgG4-RD treated with BCT301 Cell Injection. Six subjects with refractory/recurrent IgG4-RD meeting the inclusion/exclusion criteria are planned to be enrolled and will receive a single infusion of 1.8 × 10\^8 BCT301 Cell Injection to evaluate the safety, efficacy, and PK/PD characteristics following BCT301 Cell Injection infusion. The study flow consists of a screening period, a lymphodepletion pretreatment period, a treatment period, and a follow-up period. Patients without relapse or deterioration after BCT301 Cell Injection infusion and not requiring protocol-prohibited treatment will undergo a primary follow-up of up to 360 days.

02

Conditions studied

  • IgG4-related Disease
03

Who can participate

Ages eligible
18 Years to 75 Years
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • Voluntarily participate in this trial and sign the informed consent form;
  • Male or female patients aged 18 to 75 years (inclusive), with body weight ≥ 40 kg;
  • Women of childbearing potential must have a negative serum pregnancy test before the start of the trial and agree to use effective contraception during the trial and until the last follow-up; male subjects whose partners are of childbearing potential agree to use effective contraception during the trial and until the last follow-up;
  • Confirmed diagnosis of IgG4-related disease meeting the classification criteria for IgG4-RD (the 2020 updated version of the comprehensive diagnostic criteria for IgG4-RD established in Japan) or the 2019 ACR/EULAR classification criteria for IgG4-RD; and with at least one of the following organ involvements: pancreas, bile ducts, kidneys, lungs, heart or pericardium, aorta and great vessels, retroperitoneal fibrosis, sclerosing mediastinitis, dura mater, or pituitary gland;
  • Clinically meets the criteria for refractory/recurrent IgG4-RD: disease remains active, or relapses after remission, or progresses despite systemic treatment with standard-of-care regimens-glucocorticoids, immunosuppressants (cyclophosphamide, mycophenolate mofetil, methotrexate, azathioprine, etc.)-or biologic agents;
  • Currently receiving one or more of the following stable-dose standard therapies:
  • If the patient is receiving glucocorticoid therapy, the following conditions must be met: at screening and during the screening period, the maximum glucocorticoid dose is 30 mg/day of prednisone (or equivalent). The glucocorticoid dose must remain stable for ≥ 7 days prior to screening; during the screening period, glucocorticoid dose adjustments must not exceed 5 mg/day of prednisone (or equivalent);
  • If the patient is receiving immunomodulators/immunosuppressants: initiation of drug therapy must be ≥ 12 weeks prior to screening. A stable drug dose must be maintained for ≥ 4 weeks prior to screening and during the screening period;
  • If biologic agents (e.g., belimumab or telitacicept) were used before the screening period, they must be discontinued for at least 5 half-lives before screening; if anti-CD20 monoclonal antibody therapy was used before the screening period, an interval of 6 months is required before screening;
  • IgG4-RD Responder Index (RI) ≥ 2, with disease in an active state;
  • Peripheral blood B cells show positive CD19 expression by flow cytometry;
  • Major organ function must meet the following requirements (conditions caused by the immune disease itself are exempt):
  • Bone marrow hematopoietic function must meet: a. White blood cell count ≥ 3 × 10\^9/L; b. Neutrophil count ≥ 1 × 10\^9/L (no colony-stimulating factor treatment within 2 weeks prior to the examination); c. Hemoglobin ≥ 70 g/L;
  • Hepatic function: Alanine aminotransferase (ALT) ≤ 3 × upper limit of normal (ULN), aspartate aminotransferase (AST) ≤ 3 × ULN, total bilirubin (TBIL) ≤ 2 × ULN (excluding Gilbert syndrome, for which total bilirubin ≤ 3.0 × ULN);
  • Renal function: Creatinine clearance ≥ 40 mL/min (Cockcroft-Gault formula);
  • Coagulation function: International normalized ratio (INR) \< 1.5 × ULN, prothrombin time (PT) \< 1.5 × ULN;
  • Cardiac function: Good hemodynamic stability.

Exclusion criteria

Exclusion Criteria:

  • The patient must not participate in this study if any of the following criteria are met:
  • 1) Diseases that, after evaluation by the investigator, are considered inappropriate for participation in this study, for example life-threatening conditions;
  • 2) Reduced organ functional reserve not caused by the primary disease:
  • Neutrophil count \< 1 × 10\^9/L; lymphocyte count \< 0.3 × 10\^9/L; hemoglobin \< 70 g/L; platelet count \< 50 × 10\^9/L;
  • ALT > 3 × ULN; AST > 3 × ULN; total bilirubin > 2 × ULN;
  • Creatinine clearance \< 40 mL/min, estimated glomerular filtration rate (eGFR) \< 30 mL/min/1.73 m², or serum creatinine > 2.5 mg/dL;
  • Left ventricular ejection fraction ≤ 45% as diagnosed by echocardiography;
  • Blood oxygen saturation ≤ 92%;
  • 3) History of alcohol abuse or drug abuse within the past 24 weeks;
  • 4) History of malignancy other than B-cell lymphoma within the past 5 years (excluding non-melanoma skin cancer, surgically cured cervical cancer, etc.);
  • 5) Presence of infection with human immunodeficiency virus (HIV), agammaglobulinemia, T-cell deficiency virus, syphilis, chronic hepatitis B or C, or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), etc.;
  • 6) Known active tuberculosis (TB) infection or bacterial infection;
  • 7) History of myocardial infarction, coronary angioplasty or stent placement, unstable angina, active arrhythmia, or other clinically significant cardiac disease requiring clinical intervention within 6 months before the start of screening;
  • 8) History of symptomatic deep vein thrombosis or pulmonary embolism within 6 months before the start of screening;
  • 9) Known severe allergic reactions to cell-therapy-related components or their excipients, or to other immunotherapeutic agents;
  • 10) Prior organ transplantation requiring long-term immunosuppressive medication;
  • 11) Known simultaneous participation in other clinical trials affecting the disease or treatment;
  • 12) Prior treatment with CD19- and/or BCMA-targeted therapy or any CAR-T cell product targeting any antigen; unless, as assessed by the investigator, the prior treatment has clearly failed (including failure to achieve remission after treatment, remission duration below the required standard, or disease progression), the current disease state is suitable for treatment in this study, and there is no clear evidence that toxicity related to prior treatment may affect the safety of this study;
  • 13) Severe psychiatric illness and severe cognitive impairment;
  • 14) Pregnant or lactating women, or women planning pregnancy;
  • 15) Any condition considered by the investigator to be inappropriate for enrollment in this clinical trial.
04

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
6 participants (estimated)

Study arms

  • Experimental
    BCT301 Cell Injection therapy group

    Other: BCT301 Cell Injection

Interventions

  • OtherBCT301 Cell Injection

    BCT301 Cell Injection are CAR-iT cells derived from chemically induced pluripotent stem cells. Six subjects with refractory/recurrent IgG4-RD meeting the inclusion/exclusion criteria are planned to be enrolled and will receive a single infusion of 1.8 × 10\^8 BCT301 Cell Injection to evaluate the safety, efficacy, and PK/PD characteristics following BCT301 Cell Injection infusion.

05

What researchers measure

Primary outcomes

  1. The safety and tolerability of BCT301 Cell Injection in patients with refractory/recurrent IgG4-RD.

    The occurrence of cell-infusion-related adverse events within 28 days after BCT301 Cell Injection infusion, with special emphasis on cell-therapy-specific adverse reactions such as CRS and ICANS.

    Time frame: 28 days after BCT301 Cell Injection infusion

Secondary outcomes

  1. The change in IgG4-RD RI from baseline at 180 days after BCT301 Cell Injection infusion.

    This endpoint evaluates the absolute change in the IgG4-Related Disease Responder Index (IgG4-RD RI) score from baseline to Day 180 post-infusion. The IgG4-RD RI is a validated, disease-specific composite scoring system that quantifies organ involvement and disease activity across multiple domains (e.g., head/neck, chest, retroperitoneum, etc.). The change is calculated as the Day 180 score minus the baseline score; a negative value indicates improvement (reduction in disease activity), while a positive value indicates worsening. This continuous variable complements the binary response rate endpoint by providing a more granular assessment of the degree of clinical improvement or deterioration over time, and will be analyzed using descriptive statistics (mean, median, standard deviation) as well as inferential tests (e.g., paired t-test or Wilcoxon signed-rank test) for within-subject change.

    Time frame: 180 days after BCT301 Cell Injection infusion.

  2. IgG4-RD RI response rate (decrease ≥ 2 points from baseline) at 90 and 180 days after BCT301 Cell Injection infusion.

    This endpoint measures the proportion of subjects achieving at least a 2-point reduction from baseline in the IgG4-Related Disease Responder Index (IgG4-RD RI) at Day 90 and Day 180 post-infusion. The IgG4-RD RI is a validated disease activity scoring system; a decrease of ≥2 points is considered clinically meaningful and indicates a partial response to treatment.

    Time frame: 90, 180 days after BCT301 Cell Injection infusion.

  3. IgG4-RD complete remission rate at 180 and 360 days after BCT301 Cell Injection infusion.

    This endpoint evaluates the proportion of subjects who achieve stringent complete remission at Day 180 and Day 360. Complete remission requires all three criteria to be met simultaneously: (1) IgG4-RD RI score of 0 (no active disease manifestations); (2) prednisone dose of 0 mg/day after Week 4 (excluding any short-term glucocorticoid pulse used specifically to manage cytokine release syndrome \[CRS\] or allogeneic immune reactions, which are not counted as maintenance therapy); and (3) no documented recurrence or flare of disease activity from baseline through the assessment time point.

    Time frame: 180 and 360 days after BCT301 Cell Injection infusion.

  4. Proportion of patients with relapse after remission at 90, 180, and 360 days after BCT301 Cell Injection infusion.

    This endpoint measures the cumulative proportion of subjects who, having achieved any remission (partial or complete) after infusion, subsequently experience disease relapse at Day 90, Day 180, or Day 360. Relapse is specifically defined as an increase in IgG4-RD RI score during the follow-up period that necessitates additional therapeutic intervention not specified in the study protocol, thereby indicating loss of disease control.

    Time frame: 90, 180, and 360 days after BCT301 Cell Injection infusion.

  5. Changes in IgG4 levels at 90, 180, and 360 days after BCT301 Cell Injection infusion.

    This endpoint assesses the absolute change from baseline in serum IgG4 concentration (measured in g/L) at Day 90, Day 180, and Day 360 post-infusion.

    Time frame: 90, 180, and 360 days after BCT301 Cell Injection infusion.

  6. Physician Global Assessment (PhGA) and Patient Global Assessment (PtGA) compared with baseline.

    This endpoint evaluates the change from baseline in both the Physician Global Assessment (PhGA) and the Patient Global Assessment (PtGA), each measured using a single-item visual analogue scale (VAS) ranging from 0 to 100 mm, where 0 indicates no disease activity and 100 indicates the worst possible disease activity/symptoms. Higher scores indicate a worse outcome. Changes are assessed at predefined time points (consistent with other endpoints, e.g., 90, 180, and 360 days) to capture the treatment effect from both clinician and patient perspectives.

    Time frame: 90, 180, and 360 days after BCT301 Cell Injection infusion.

Other outcomes

  1. CAR gene copy number in peripheral blood after BCT301 Cell Injection infusion and the duration of persistence after infusion.

    This endpoint quantifies the level of CAR transgene in peripheral blood using a validated quantitative polymerase chain reaction (qPCR) assay specific to the CAR construct. CAR gene copy number is measured at baseline and at multiple post-infusion time points: Days 1, 3, 7, 10, 14, 28, 90. Results are expressed as copies per microgram of genomic DNA or copies per milliliter of blood. The persistence duration is defined as the last time point at which the CAR copy number remains above the lower limit of quantification for each subject.

    Time frame: Days 0, 1, 3, 7, 10, 14, 28, 90.

  2. Time to maximum concentration (Tmax) of CAR gene copies after BCT301 Cell Injection infusion.

    This PK parameter is derived from the CAR gene copy number-time profile. Tmax is defined as the time (in days) from the end of BCT301 infusion to the first occurrence of the peak CAR copy number (Cmax) in peripheral blood. It is estimated using non-compartmental analysis based on serial measurements collected during the early post-infusion period (Days 1, 3, 7, 10, 14, and 28). Tmax reflects the kinetics of CAR-T cell expansion and trafficking to the peripheral circulation.

    Time frame: Days 0, 1, 3, 7, 10, 14, 28, 90.

  3. Maximum concentration (Cmax) of CAR gene copies after BCT301 Cell Injection infusion.

    This PK parameter represents the peak observed CAR gene copy number in peripheral blood after infusion. Cmax is determined directly from the concentration-time data as the highest measured value ( copies/mL) during sampling period. It quantifies the maximal expansion level of the infused CAR-T cells and is a key exposure metric for correlating with efficacy and toxicity.

    Time frame: Days 0, 1, 3, 7,10, 14, 28, 90.

  4. Area under the concentration-time curve from 0 to 28 days (AUC28) of CAR gene copies after BCT301 Cell Injection infusion.

    AUC28 is the integral of the CAR gene copy number-time curve from the time of infusion (Day 0) to Day 28, calculated using the linear trapezoidal rule (or log-linear for descending part). It quantifies the total early systemic exposure to CAR-T cells over the first 28 days, capturing the initial expansion and contraction phase. Missing intermediate values are handled by standard PK imputation methods. AUC28 is expressed as copies·day/mL.

    Time frame: Days 0, 1, 3, 7, 10, 14, 28.

  5. Area under the concentration-time curve from 0 to 90 days (AUC90) of CAR gene copies after BCT301 Cell Injection infusion.

    AUC90 is the integral of the CAR gene copy number-time curve from the time of infusion to Day 90, calculated using the same non-compartmental method. It reflects the total exposure over a longer period that includes both early expansion and subsequent persistence/clearance. This parameter provides additional information on the durability of CAR-T cell persistence beyond the initial month and may better correlate with sustained pharmacodynamic effects. Measurements from Days 0, 1, 3, 7, 10, 14, 28, and 90 are used for calculation.

    Time frame: Days 0, 1, 3, 7, 10, 14, 28, and 90.

  6. The PD characteristics of B-cell count in peripheral blood after BCT301 Cell Injection infusion.

    This endpoint evaluates the pharmacodynamic (PD) effect of BCT301 Cell Injection on B-cell lineage in the peripheral blood. Absolute B-cell counts (cells/µL) are measured by flow cytometry using CD19⁺ (or CD20⁺) gating at scheduled post-infusion time points (including 0-28 days, 90, 180, and 360 days). Changes from baseline in B-cell count are calculated to assess the extent and duration of B-cell depletion or modulation induced by the CAR-T therapy. The count is expressed as absolute number per microliter, and both raw values and percentage change from baseline will be summarized descriptively.

    Time frame: 0-28 days, 90, 180, and 360 days after BCT301 Cell Injection infusion.

  7. Cytokine changes following BCT301 infusion.

    This endpoint measures serial changes in serum/plasma concentrations of six pro-inflammatory and immunomodulatory cytokines (IL-6, IL-10, IL-2, IL-8, TNF-α, and IFN-γ) following BCT301 infusion. Cytokine levels are quantified using a validated multiplex immunoassay (e.g., Luminex or electrochemiluminescence) at baseline and at multiple post-infusion time points (0-28 days, 90, 180, and 360 days). For each cytokine, the absolute change and percentage change from baseline are calculated. These data are used to monitor cytokine release syndrome (CRS) risk and to explore the relationship between cytokine dynamics and clinical efficacy/toxicity.

    Time frame: 0-28 days, 90, 180, and 360 days after BCT301 infusion.

  8. B-cell subset changes following BCT301 Cell Injection infusion.

    This endpoint evaluates the phenotypic redistribution of B-cell subpopulations in peripheral blood after BCT301 infusion. Using multicolor flow cytometry with defined gating strategies, the following proportional measures are derived at baseline and at post-infusion time points (0-28 days, 90, 180, and 360 days): (1) total B cells as % of lymphocytes (CD19⁺ or CD20⁺); (2) naive B cells (CD19⁺CD27-IgD⁺) as % of B cells; (3) memory B cells (CD19⁺CD27⁺) as % of B cells; (4) class-switched memory B cells (CD19⁺CD27⁺IgD-) as % of B cells; (5) unswitched memory B cells (CD19⁺CD27⁺IgD⁺) as % of B cells; (6) plasmablasts (CD19⁺CD38⁺CD27⁺) as % of B cells; and (7) immature/transitional B cells (CD19⁺CD20⁺CD21-CD27-) as % of CD19⁺CD20⁺ cells. Changes from baseline for each subset proportion are calculated to assess the impact of CAR-T therapy on B-cell maturation and reconstitution, which may correlate with humoral immune recovery and long-term disease control.

    Time frame: 0-28 days, 90, 180, and 360 days after BCT301 Cell Injection infusion.

06

Study locations

No study locations are listed for this record.

07

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

08

Registry details

Key details

Study ID
NCT07793903
Lead sponsor
Peking University Third Hospital
Responsible party
Mu Rong (Professor, Director of Department of Rheumatology & Immunology, Peking University Third Hospital) — Principal investigator
First posted
Aug 31, 2026
Start date
Oct 2026 (estimated)
Primary completion
Jun 2028 (estimated)
Completion
Feb 2030 (estimated)
Last update
Aug 31, 2026

Study contacts

Jinxia Zhao, MD
Contact
zhao-jinxia@163.com
8610 82265699

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
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