A Study to Evaluate the Safety and Tolerability of Efgartigimod PH20 SC Given by Prefilled Syringe in Kidney Transplant Recipients With Antibody-Mediated Rejection (AMR) (Shamrock)

March 16, 2026 updated by: argenx

A Global, Multicenter, Randomized, Double-Blinded, Placebo-Controlled, Phase 2 Study to Evaluate the Safety, Tolerability, and Efficacy of Efgartigimod PH20 SC Administered by a Prefilled Syringe in Kidney Transplant Recipients With Antibody-Mediated Rejection

The purpose of this study is to assess the safety, tolerability, and efficacy of efgartigimod PH20 SC given by a prefilled syringe in participants with Antibody-Mediated Rejection (AMR) after kidney transplantation.

After a screening period of up to 6 weeks, eligible participants will be randomized in a 1:1:1 ratio. The study drug will be administered subcutaneously while patients remain on their standard background immunosuppression therapy (tacrolimus, mycophenolate mofetil, steroids) during the treatment period (48 weeks). At the end of the treatment period, the participants will enter an observational/follow-up period (approximately 24 weeks). The participants will be in the study for up to 78 weeks.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Phase 2

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 Locations

  • Austria
      • Vienna, Austria, 1090
        • Recruiting
        • Allgemeines Krankenhaus der Stadt Wien (AKH Wien) - Medizinischer Universitätscampus
        • Contact:
  • Belgium
      • Ghent, Belgium, 9000
        • Recruiting
        • Universitair Ziekenhuis (UZ) Gent
        • Contact:
      • Leuven, Belgium, 3000
        • Recruiting
        • Universitair Ziekenhuis Leuven (UZ Leuven) - Campus Gasthuisberg
        • Contact:
  • Canada
      • London, Canada, N6A 5A5
        • Recruiting
        • London Health Sciences Centre
        • Contact:
  • Czechia
      • Prague, Czechia, 140-21
        • Recruiting
        • Institut klinicke a experimentalni mediciny (IKEM)
        • Contact:
  • France
      • Bordeaux, France, 33076
        • Recruiting
        • Centre Hospitalier Universitaire (CHU) de Bordeaux - Hôpital Pellegrin
        • Contact:
      • La Tronche, France, 38700
        • Recruiting
        • Centre Hospitalier Universitaire (CHU) de Grenoble Alpes - Hôpital Michallon
        • Contact:
      • Toulouse, France, 31059
        • Recruiting
        • Centre Hospitalier Universitaire (CHU) de Toulouse - Hôpital de Rangueil
        • Contact:
  • Germany
      • Berlin, Germany, 13353
        • Recruiting
        • Charite - Universitatsmedizin Berlin
        • Contact:
      • Dresden, Germany, 01307
        • Recruiting
        • Universitaetsklinikum Carl Gustav Carus Dresden
        • Contact:
      • Hamburg, Germany, 20246
        • Recruiting
        • Universitätsklinikum Hamburg-Eppendorf
        • Contact:
  • Spain
      • Barcelona, Spain, 08003
      • Barcelona, Spain, 08907
        • Recruiting
        • Hospital Universitario de Bellvitge
        • Contact:
      • Barcelona, Spain, 08035
        • Recruiting
        • Hospital Universitario Vall d'Hebron
        • Contact:
      • Zaragoza, Spain, 50009
        • Recruiting
        • Hospital Universitario Miguel Servet
        • Contact:
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • Recruiting
        • University of Alabama at Birmingham (UAB) Hospital
        • Contact:
    • California
      • Los Angeles, California, United States, 90048
        • Recruiting
        • Cedars-Sinai Medical Center
        • Contact:
    • Illinois
      • Chicago, Illinois, United States, 60615
        • Recruiting
        • University of Chicago Medical Center
        • Contact:
    • Nebraska
      • Omaha, Nebraska, United States, 68198
        • Recruiting
        • University of Nebraska Medical Center
        • Contact:
    • North Carolina
      • Durham, North Carolina, United States, 27705
        • Recruiting
        • Duke University Hospital
        • Contact:
    • Ohio
      • Columbus, Ohio, United States, 43210
        • Recruiting
        • The Ohio State University Wexner Medical Center
        • Contact:
    • Virginia
      • Richmond, Virginia, United States, 23298
        • Recruiting
        • Virginia Commonwealth University (VCU) Medical Center Hume-Lee Transplant Center
        • Contact:
    • Washington
      • Seattle, Washington, United States, 98195
        • Recruiting
        • University of Washington Medical Center
        • Contact:

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • The participant is within the ages of 18 and 80 years old
  • The participant had a kidney transplant (living or deceased donor) at least 6 months before the study
  • The participant has received a diagnosis of active or chronic active antibody-mediated rejection (AMR) with detectable donor-specific antibodies at time of the study

  • A participant may be allowed into the study if they receive the following medications:

    1. Received mycophenolate mofetil for at least 20 weeks before the study
    2. Has remained on a stable dose of mycophenolate mofetil and tacrolimus for at least 4 weeks before being allowed to participate in the study
    3. Has remained on tacrolimus doses between 5 to 10 ng/mL at least 4 weeks before being allowed to participate in the study
    4. Steroid dose was between 0 to 10 mg per day of prednisone (or dose equivalent) for at least 4 weeks before being allowed to participate in the study

Exclusion Criteria:

  • Confirmed T-cell or mixed rejection at time of the study
  • Recent change in immunosuppressive therapy agents
  • Any other medical condition that, in the investigator's opinion, would interfere with the results of the study or put the participant at undue risk
  • Pregnant or lactating state or intention to become pregnant during the study

The complete list of criteria can be found in the protocol

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Treatment arm 1
Participants receiving Efgartigimod PH20 SC on top of optimized standard background immunosuppression therapy (tacrolimus, mycophenolate mofetil, and optionally steroids)
Combination product: Efgartigimod PH20 SC - prefilled syringe
Subcutaneous efgartigimod PH20 SC given by prefilled syringe
Experimental: Treatment arm 2
Participants receiving Efgartigimod PH20 SC on top of optimized standard background immunosuppression therapy (tacrolimus, mycophenolate mofetil, and optionally steroids) up to week 24 followed by placebo PH20 SC on top of optimized standard background immunosuppression therapy from weeks 24 to 48
Combination product: Efgartigimod PH20 SC - prefilled syringe
Subcutaneous efgartigimod PH20 SC given by prefilled syringe
Other: Placebo PH20 SC - prefilled syringe
Subcutaneous placebo PH20 SC given by prefilled syringe
Placebo Comparator: Treatment arm 3
Participants receiving Placebo PH20 SC on top of optimized standard background immunosuppression therapy (tacrolimus, mycophenolate mofetil, and optionally steroids)
Other: Placebo PH20 SC - prefilled syringe
Subcutaneous placebo PH20 SC given by prefilled syringe

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence of Adverse Events (AEs)
Time Frame: Up to 78 weeks
Up to 78 weeks
Percentage of participants with permanent treatment discontinuation due to adverse events (AEs)
Time Frame: Up to 48 weeks
Up to 48 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Changes from baseline (slope) of the estimated glomerular filtration rate (eGFR)
Time Frame: Up to 72 weeks
Up to 72 weeks
Histological changes in kidney biopsy
Time Frame: Up to 72 weeks
Up to 72 weeks
Urine protein creatinine ratio (UPCR)
Time Frame: Up to 72 weeks
Up to 72 weeks
Graft and participant survival
Time Frame: Up to 72 weeks
Up to 72 weeks
Percentage change from baseline in total IgG levels in serum over time
Time Frame: Up to 60 weeks
Up to 60 weeks
Efgartigimod serum concentration-time profile and PK parameter Ctrough
Time Frame: Up to 48 weeks
Up to 48 weeks
Incidence of antidrug antibodies (ADA) against efgartigimod in serum over time
Time Frame: Up to 72 weeks
Up to 72 weeks
Incidence of antibodies against rHuPH20 in plasma over time
Time Frame: Up to 72 weeks
Up to 72 weeks

Collaborators and Investigators

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

Sponsor

argenx

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 30, 2024

Primary Completion (Estimated)

September 1, 2027

Study Completion (Estimated)

September 1, 2027

Study Registration Dates

First Submitted

July 10, 2024

First Submitted That Met QC Criteria

July 10, 2024

First Posted (Actual)

July 16, 2024

Study Record Updates

Last Update Posted (Actual)

March 18, 2026

Last Update Submitted That Met QC Criteria

March 16, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • ARGX-113-2302
  • 2023-508180-72-00 (Ctis)

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

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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