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NCT Number: NCT07613359

A Study of Mezagitamab in Adults With Late Antibody-Mediated Rejection (AMR) After a Kidney Transplant

Antibody-mediated rejection (AMR) is a major cause of worsening kidney function after a kidney transplant (kidney allograft dysfunction) and can lead to kidney failure. AMR happens when the kidney recipient's immune system makes antibodies that attack the donor kidney. Antibodies are proteins made by the immune system to recognize foreign cells. Over time, this attack can damage kidney tissue and cause the transplant to fail. Because AMR can be serious, there is a need for treatments that are safe, work well, and are supported by good evidence.

The main aim of this study is to find out how safe mezagitamab is and how well adults with AMR tolerate it compared with placebo. A placebo looks like medicine but has no active ingredients. The study will also look at whether mezagitamab helps to control inflammation in the transplanted kidney and helps keep kidney function stable, compared with placebo.

Participants will be placed by chance in 1 of the 3 treatment groups in equal numbers. Two groups will receive mezagitamab in two different doses. One group will receive placebo. This means that out of every 3 participants, 2 will receive mezagitamab and 1 will receive placebo.

During the study, participants will visit their study clinic several times.

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Key information

Conditions

Antibody-Mediated Rejection (AMR)

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key inclusion criteria:

  • The participant aged 18 to 80 years.
  • The participant must have a biopsy-confirmed diagnosis of active or chronic active late AMR (defined as greater than [>] 6 month after kidney transplant) without concurrent definitive TCMR (Grade 1a and above) as defined by the 2022 Banff classification.
  • Biopsy within 30 days prior to screening, or performed during screening period within protocol-defined window.
  • If the participant has received treatment for rejection, then the repeat biopsy and donor specific antibody (DSA) testing must have been performed at least 6 weeks after stopping the treatment.
  • The participant with either human leukocyte antigen (HLA) class I and/or II DSA.
  • eGFR > 30 milliliters per minute per 1.73 square meters (mL/min/1.73m^2).

Key exclusion criteria:

  • The participant has blood type A, B, AB, or O (ABO) incompatible transplant.
  • The participant has a history of multiple organ transplants, including en bloc and dual kidney transplants.
  • Participant likely to require renal replacement therapy within the subsequent 30 days.
  • Participants who have received an anti-cluster of differentiation 38 (CD38) therapy in the last 1 year or have past history of failing to achieve AMR resolution despite treatment with an anti-CD38 therapy.
  • The participant has received any previous treatment with other immunosuppressant or immunomodulatory therapy:

a) Within 6 months of signing the informed consent form (ICF) as listed below:

  • Complement system inhibitors (such as, eculizumab).
  • Proteasome inhibitors (such as, bortezomib).
  • Interleukin-6 (IL-6)/IL-6R antibody (such as, tocilizumab).
  • Anti-cluster of differentiation 20 (CD20) antibody (such as, rituximab). b) Within 6 weeks of signing the ICF as listed below:
  • Intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (SCIG) or plasmapheresis
  • The participant has active infection with hepatitis B virus, hepatitis C virus (HCV), or human immunodeficiency virus (HIV).
  • Participant with serious infection within 2 weeks or with opportunistic infection within 2 months prior to signing ICF. Participant with active or untreated tuberculosis, or those with high suspicion of tuberculosis are also excluded.
  • History of malignancy (including myelodysplastic syndrome) within 5 years of signing the ICF, except for adequately treated non-melanoma skin cancer, superficial bladder cancer, and curatively treated cervical carcinoma-in-situ.

Key Note: Other protocol specified inclusion and exclusion criteria apply.

Treatment and study plan

Mezagitamab

Drug

Mezagitamab subcutaneous (SC) injection.

Other names: TAK-079

Placebo

Drug

Mezagitamab-matching placebo SC injection.

Primary outcomes

  1. Arms A, B, and C: Number of Participants With Treatment-Emergent Adverse Events (TEAEs)

    Time frame: Up to Week 70

    An adverse event (AE) is any untoward medical occurrence in a clinical trial participant, temporally associated with the use of the trial intervention, whether or not the occurrence is considered related to the trial intervention. An AE can be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of the trial intervention. TEAEs are defined as AEs with start dates at the time of or following the first exposure to investigational medicinal product (IMP).

  2. Arms A, B, and C: Number of Participants With Related TEAEs

    Time frame: Up to Week 70

    A related AE is an AE that is considered related to the IMP. Related TEAEs are defined as related AEs with start dates at the time of or following the first exposure to IMP.

  3. Arms A, B, and C: Number of Participants With Serious Adverse Events (SAEs)

    Time frame: Up to Week 70

    An SAE is any untoward medical occurrence that results in death, is life threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity or is a congenital anomaly/birth defect.

  4. Arms A, B, and C: Number of Participants With AEs of Special Interest

    Time frame: Up to Week 70

    AEs of special interest are AEs that are considered specific to the IMP.

  5. Arms A, B, and C: Number of Participants With AE Leading to Treatment Discontinuation

    Time frame: Up to Week 70

  6. Arms A, B, and C: Number of Participants With Clinically Significant Abnormal Laboratory Test Results and Vital Signs

    Time frame: Up to Week 70

Secondary outcomes

  1. Arms A, B, and C: Percentage of Participants With Achievement of Biopsy-Proven Histologic Resolution of AMR Activity at Weeks 24 and 48

    Time frame: Weeks 24 and 48

    Achievement of biopsy-proven histological resolution of AMR activity will be assessed by the 2022 Banff classification criteria. The Banff 2022 Classification provides a standardized framework for evaluating kidney transplant biopsies using lesion scoring.

  2. Arms A, B, and C: Microvascular Inflammation (MVI) Score in Biopsy Samples at Weeks 24 and 48

    Time frame: Weeks 24 and 48

    MVI is an important marker of allograft loss and is defined as the sum of glomerulitis and peritubular capillaritis scores (g+ptc) on kidney histology.

  3. Arms A, B, and C: Percentage of Participants Who Achieve a MVI Score of 0 at Weeks 24 and 48

    Time frame: Weeks 24 and 48

  4. Arms A, B, and C: Change From Baseline in MVI score at Weeks 24 and 48

    Time frame: Baseline, Weeks 24 and 48

  5. Arms A, B, and C: Change From Baseline in Estimated Glomerular Filtration Rate (eGFR) at Weeks 24, 48 and 70

    Time frame: Baseline, Weeks 24, 48 and 70

    eGFR is a measure of kidney function calculated from serum creatinine using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.

  6. Arms A, B, and C: Change From Baseline in Donor-Derived Cell-Free DNA (dd-cfDNA) at Weeks 24, 48 and 70

    Time frame: Baseline, Weeks 24, 48 and 70

    dd-cfDNA are DNA fragments released from injured donor cells. It serves as a noninvasive, quantitative method that reflects allograft injury and is associated with AMR activity in kidney transplant recipients.

  7. Arms A, B, and C: Change From Baseline in Urine Protein Creatinine Ratio (UPCR) at Weeks 24, 48 and 70

    Time frame: Baseline, Weeks 24, 48 and 70

    UPCR is a measure of protein excretion calculated from a urine sample, as the ratio of urine protein to creatinine, and used to assess kidney function.

  8. Arm B: Percentage of Participants With Achievement of Biopsy-Proven Histologic Resolution of AMR Activity at Week 70

    Time frame: Week 70

  9. Arm B: MVI Score in Biopsy Samples at Week 70

    Time frame: Week 70

  10. Arm B: Percentage of Participants Who Achieve a MVI Score of 0 at Week 70

    Time frame: Week 70

  11. Arm B: Change From Baseline in MVI score at Week 70

    Time frame: Week 70

  12. Arms A, B, and C: Percentage of Participants With T-Cell Mediated Rejection (TCMR) by Biopsy at Weeks 24 and 48

    Time frame: Weeks 24 and 48

  13. Arm B: Percentage of Participants With TCMR by Biopsy at Week 70

    Time frame: Week 70

  14. Arms A and B: Serum Concentration of Mezagitamab

    Time frame: Pre-dose and at multiple time points post-dose up to Week 70

  15. Arms A, B and C: Number of Participants With Anti-Drug Antibody

    Time frame: Pre-dose and at multiple time points post-dose up to Week 70

  16. Arms A, B and C: Number of Participants With Neutralizing Antibody

    Time frame: Pre-dose and at multiple time points post-dose up to Week 70

Study contacts

Contact information is provided by the study sponsor or research team.

Takeda Contact

CONTACT

[email protected]

+1-877-825-3327

Sponsors and collaborators

Lead sponsor

Takeda

Industry

Registry information

Official study title

A Double-Blind, Placebo-Controlled, Multicenter, Randomized, Phase 2 Trial to Evaluate the Safety and Efficacy of Mezagitamab (TAK-079) in Kidney Transplant Recipients With Late Antibody-Mediated Rejection (AMR)

Important dates

Study start
2026
Primary completion
2029
Study completion
2029
First posted
May 29, 2026
Registry last updated
Jun 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.