CD38 mAb Induction + Azathioprine Maintenance for Chronic Active AMR in Kidney Transplant Recipients (CAZA)

July 16, 2026 updated by: wujianyong

A Multicenter Exploratory Clinical Study of Targeted NK Cell Inhibition for Transplant Kidney Chronic Active Antibody-Mediated Rejection (caABMR): Single Induction With CD38 Monoclonal Antibody Followed by Sequential Maintenance With Azathioprine

This multicenter, prospective, single-arm exploratory study evaluates the efficacy and safety of a novel sequential regimen for chronic active antibody-mediated rejection (caABMR) in kidney transplant recipients: single-dose CD38 monoclonal antibody (1800 mg subcutaneous) induction to deplete plasma cells and NK cells, followed by long-term maintenance with azathioprine (replacing mycophenolate mofetil) plus standard triple immunosuppression (steroid + calcineurin inhibitor). The regimen aims to control DSA-driven injury, stabilize or improve graft function (primary: eGFR decline slope), reduce DSA, improve pathology (Banff 2022), and minimize infection/nephrotoxicity risks associated with intensified or prolonged biologic therapy. Twenty patients across 6 Chinese transplant centers will be enrolled. CD38 mAb, azathioprine, key monitoring tests (HLA antibody, pharmacogenomics, immune profiling) are provided free by the study team (~40,000 RMB per patient). Ethics approved; informed consent obtained.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background: caABMR is the leading cause of late kidney allograft loss. Current therapies (plasmapheresis, IVIG, rituximab, bortezomib, long-term CD38 mAb) have limited efficacy, high recurrence, significant side effects, and high cost with no approved standard.

Rationale: CD38 mAb depletes antibody-producing plasma cells and pathogenic NK cells, rapidly lowering DSA and micro vascular inflammation. However, long-term monotherapy is costly and may increase infection risk. This study uses single induction dose + switch to azathioprine (safe, inexpensive, long-used in transplantation, suppresses NK activity) for durable, affordable maintenance. TPMT/NUDT15 genotyping guides personalized AZA dosing; serial NK cell monitoring targets <20/μL.

Design: Multicenter (6 centers), prospective, open-label, single-arm, exploratory (N=20).

Intervention: Baseline: CD38 mAb 1800 mg SC x1 + immediate switch MMF→AZA (dose per genotype: normal metabolizer 2-3 mg/kg/d; intermediate 0.6-2.4 mg/kg/d). Maintain triple IS (steroid + AZA + Tac target 5-7 ng/mL or CsA 150-250 ng/mL).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Voluntary written informed consent.
  2. Age ≥18 years.
  3. Kidney transplant (living or deceased donor) ≥180 days prior.
  4. eGFR ≥30 mL/min/1.73 m² (CKD-EPI 2021).
  5. Currently on stable triple immunosuppression (CNI + MMF + steroid) for ≥4 weeks, no severe related adverse effects.
  6. Positive HLA Class I and/or Class II donor-specific antibodies (DSA).
  7. Transplant kidney biopsy meeting Banff 2022 criteria for chronic active antibody-mediated rejection (caABMR).
  8. TPMT/NUDT15 genotyping: non-homozygous mutant (normal or intermediate metabolizer).

Exclusion Criteria:

  1. Participating in another clinical trial.
  2. Age <18 years.
  3. Pregnant, breastfeeding, or inadequate contraception in females.
  4. ABO-incompatible transplant.
  5. TPMT/NUDT15 homozygous mutant genotype.
  6. Biopsy shows any of: T-cell mediated rejection (TCMR), new/recurrent severe thrombotic microangiopathy, or polyomavirus nephropathy.
  7. Received anti-rejection therapy in prior 3 months.
  8. Received other immunomodulatory monoclonal/polyclonal antibodies (anti-CD20, bortezomib, anti-C5, anti-IL-6/IL-6R) in prior 3 months.
  9. Total bilirubin >2×ULN or ALT/AST >2.5×ULN.
  10. Hemoglobin <8 g/dL.
  11. Platelets <100×10^9/L.
  12. WBC <3×10^9/L or neutrophils <1.5×10^9/L.
  13. Hypogammaglobulinemia: IgG <400 mg/dL.
  14. Active bacterial, viral, or fungal infection.
  15. Active malignancy requiring intensified immunosuppression.
  16. Latent or active tuberculosis.
  17. Live vaccine within 6 weeks of screening.
  18. History of alcohol or illicit drug abuse.
  19. Severe medical or psychiatric illness likely to impair study participation.
  20. Active hepatitis B.
  21. Known hypersensitivity to CD38 mAb, azathioprine, or study drug components, or severe drug allergy history.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Experimental: CD38 mAb Induction + Azathioprine Sequential Maintenance

All enrolled caABMR patients receive:

  • Single subcutaneous injection of CD38 monoclonal antibody 1800 mg at baseline (Day 0).
  • Immediate conversion from mycophenolate mofetil to azathioprine (AZA), dosed according to TPMT/NUDT15 genotype and adjusted to achieve NK cell count <20/μL.
  • Continued standard triple immunosuppression: corticosteroid + azathioprine + tacrolimus (trough 5-7 ng/mL) or cyclosporine (trough 150-250 ng/mL).
  • Protocol-driven monitoring and 28-week surveillance biopsy. No control arm (single-arm exploratory design justified by lack of approved therapy and emerging evidence for CD38 targeting in AMR).
Biological: CD38
Single 1800 mg subcutaneous injection at baseline to induce rapid depletion of plasma cells (source of DSA) and NK cells (key effectors of microvascular injury in caABMR). Marketed anti-CD38 mAb (off-label use in this indication).
Other Names:
  • CD38 mAb
  • anti-CD38 monoclonal antibody
Drug: Azathioprine (AZA)
Oral azathioprine maintenance (replaces mycophenolate), individualized starting dose 2.0-3.0 mg/kg/day (normal TPMT/NUDT15 metabolizer) or 30-80% reduced (intermediate metabolizer), titrated per serial NK cell counts and hematologic tolerance. Long-term NK suppression to maintain immune balance and protect graft.
Other Names:
  • AZA
  • Imuran (or generic)
Other: Standard Triple Immunosuppression Maintenance
Continued per local practice with protocol targets

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Slope of estimated glomerular filtration rate (eGFR) decline
Time Frame: Baseline through Week 28, planned assessments at weeks 0, 4, 8, 12, 16, 20, 24, 28
The primary efficacy endpoint is the slope of eGFR decline over 28 weeks, calculated from serial serum creatinine measurements (every 4 weeks) using the 2021 CKD-EPI equation. Serum creatinine is measured by enzymatic method or isotope dilution mass spectrometry. Slope is estimated via linear mixed-effects model or ordinary least-squares regression per patient, then summarized. Negative slope indicates ongoing graft loss; less negative or positive slope indicates stabilization or improvement of renal function after treatment.
Baseline through Week 28, planned assessments at weeks 0, 4, 8, 12, 16, 20, 24, 28

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in peripheral blood NK cell, T cell and B cell subset counts and percentages measured by flow cytometry
Time Frame: Baseline, Week 1, Week 2, Week 4, Week 8, Week 12, Week 16, Week 20, Week 24, Week 28
Quantitative detection of lymphocyte subpopulations (NK, T, B cells) in peripheral blood via flow cytometry; evaluate the absolute count and relative percentage changes at each follow-up time point.
Baseline, Week 1, Week 2, Week 4, Week 8, Week 12, Week 16, Week 20, Week 24, Week 28
Absolute and relative percentage change in estimated glomerular filtration rate calculated by CKD-EPI 2021 formula
Time Frame: Baseline, Week 1, Week 2, Week 4, Week 8, Week 12, Week 16, Week 20, Week 24, Week 28
Estimated glomerular filtration rate (eGFR) is calculated by the CKD-EPI 2021 formula. Both absolute value and relative percentage change of eGFR will be evaluated at all scheduled follow-up visits.
Baseline, Week 1, Week 2, Week 4, Week 8, Week 12, Week 16, Week 20, Week 24, Week 28
Percentage change in urine protein-to-creatinine ratio (UPCR)
Time Frame: Baseline and Week 28
Urine protein-to-creatinine ratio (UPCR) measured in mg/g or mg/mmol. Urine protein is tested via pyrogallol red molybdate method, and creatinine is detected using sarcosine oxidase assay. The relative percentage change of UPCR is used to evaluate renal therapeutic efficacy.
Baseline and Week 28
Relative percentage change in donor-specific antibody (DSA) mean fluorescence intensity (MFI)
Time Frame: Baseline, Week 8, Week 28
Donor-specific antibody MFI is detected via Luminex single-antigen bead assay. Relative percentage change from baseline will be calculated to evaluate the reduction of alloantibody levels.
Baseline, Week 8, Week 28
Change in Transplant Kidney Biopsy Pathology Scores (Banff 2022)
Time Frame: Baseline, Week 28
Banff 2022 renal allograft pathology scoring system is applied for the interpretation of protocol kidney biopsy specimens. The scores include microcirculation inflammation, tubulitis, interstitial inflammation, chronic glomerulopathy, transplant glomerulitis and chronic arteriopathy. The pathological scores are recorded at screening baseline and week-28 follow-up biopsy. The variation of each individual Banff lesion score between two time-points will be analyzed. Higher Banff lesion scores represent more severe renal allograft injury.
Baseline, Week 28
Incidence of Acute Rejection (TCMR, AMR, or Mixed)
Time Frame: Through Week 28
Cumulative incidence (%) of biopsy-proven acute rejection, including T cell-mediated rejection (TCMR), antibody-mediated rejection (AMR), and mixed rejection, diagnosed according to Banff 2022 classification criteria.
Through Week 28
Patient overall survival rate
Time Frame: Week 28
The proportion of subjects who remain alive without all-cause mortality at the designated follow-up time point
Week 28
Graft survival rate
Time Frame: Week 28
Percentage of participants with functioning renal allograft, defined as no return to maintenance dialysis and no secondary kidney retransplantation
Week 28
Incidence of BK Virus (BKV) Infection
Time Frame: Through Week 28
Cases of BK virus infection are categorized as BKV viruria (>10³ copies/mL), BKV viremia (≥10⁴ copies/mL), or biopsy-confirmed BKV nephropathy identified by renal histology combined with SV40 IHC or ISH staining. Cumulative incidence percentage will be calculated for each category.
Through Week 28
Incidence of Cytomegalovirus (CMV) Infection
Time Frame: Through Week 28
Cytomegalovirus infection is defined as detectable CMV DNA ≥10³ copies/mL quantified via quantitative PCR (qPCR). Cumulative incidence percentage of affected subjects will be summarized.
Through Week 28
Incidence of Neutropenia
Time Frame: Through Week 28
Neutropenia is stratified by absolute neutrophil count (ANC): mild ANC <1.5×10⁹/L, moderate ANC <1.0×10⁹/L, severe ANC <0.5×10⁹/L. Cumulative incidence percentage will be stratified by severity grades defined per NCI CTCAE or study protocol criteria.
Through Week 28

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Outcome Measure Title：Incidence of injection-related adverse reactions
Time Frame: Through Week 28
All infusion-related adverse events during the whole follow-up period will be recorded, including fever, chills, hypotension, dyspnea and other infusion-associated manifestations.
Through Week 28
Incidence of adverse events (AE) and serious adverse events (SAE)
Time Frame: Through Week 28
The type, severity, relation to study medication and occurrence frequency of all adverse events and serious adverse events will be collected, according to CTCAE common terminology criteria.
Through Week 28
Incidence of liver function abnormalities
Time Frame: Through Week 28
Liver function indexes including alanine transaminase, aspartate transaminase, total bilirubin will be tested regularly. Liver function abnormality is defined as laboratory elevation exceeding 3-fold upper limit of normal range.
Through Week 28
Incidence of all-cause hospitalization
Time Frame: Through Week 28
All hospitalization events for any reason during follow-up will be documented, including the admission time, diagnosis and length of hospital stay.
Through Week 28

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
wujianyong

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jianyong Wu, MD, Zhejiang University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

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Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 15, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 15, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 15, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 11, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 21, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 21, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 16, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IIT20260074C-R1

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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