RESET-Myositis: An Open-Label Study to Evaluate the Safety and Efficacy of CABA-201 in Subjects With Active Idiopathic Inflammatory Myopathy or Juvenile Idiopathic Inflammatory Myopathy

May 12, 2026 updated by: Cabaletta Bio

A Phase 1/2, Open-Label Study to Evaluate the Safety and Efficacy of Autologous CD19-specific Chimeric Antigen Receptor T Cells (CABA-201) in Subjects With Active Idiopathic Inflammatory Myopathy or Juvenile Idiopathic Inflammatory Myopathy

RESET-Myositis: Open-Label Study to Evaluate the Safety and Efficacy of CABA-201 in Subjects with Active Idiopathic Inflammatory Myopathy or Juvenile Idiopathic Inflammatory Myopathy

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Idiopathic inflammatory myopathies (IIMs, or myositis) are a group of rare autoimmune diseases characterized by inflammation and muscle weakness. Though the cause of IIM is not well understood, some subtypes of IIM, including dermatomyositis (DM), anti-synthetase syndrome (ASyS), immune-mediated necrotizing myopathy (IMNM), and juvenile idiopathic inflammatory myopathy (JIIM), are thought to involve B cells that cause the body to attack different tissues in the body. This study is being conducted to evaluate the safety and efficacy of an investigational cell therapy, CABA-201, that can be given to patients with DM, ASyS, IMNM, or JIIM who have active disease. A single dose of CABA-201 in combination with cyclophosphamide (CY) and fludarabine (FLU) will be evaluated.

Study Type

Interventional

Enrollment (Estimated)

74

Phase

  • Phase 2
  • Phase 3

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

  • United Kingdom
    • United Kingdom
      • London, United Kingdom, United Kingdom, SE5 9RS
        • Recruiting
        • Kings College Hospital NHS Foundation Trust - Accepting Adult Patients
        • Contact:
        • Principal Investigator:
          • Patrick Gordon, PhD, FRCP, MBBS
      • London, United Kingdom, United Kingdom, WC1N 3BG
        • Recruiting
        • University College London Hospitals NHS Foundation Trust - Accepting Adult Patients
        • Contact:
        • Principal Investigator:
          • Dr. Pedro Machado, FRCP, PhD
      • Manchester, United Kingdom, United Kingdom, M13 9WL
        • Recruiting
        • Manchester Royal Infirmary - Accepting Adult Patients
        • Contact:
        • Principal Investigator:
          • Eleni Tholouli, MD, PhD, MRCP(UK), FRCPath
      • Salford, United Kingdom, United Kingdom, M6 8HD
        • Recruiting
        • Salford Royal Hospital - Accepting Adult Patients
        • Contact:
        • Principal Investigator:
          • Hector Chinoy, PhD, FRCP, MSc, BMBS, BMedSci
  • United States
    • California
      • Orange, California, United States, 92868
        • Recruiting
        • University of California Irvine - Accepting Adult Patients
        • Principal Investigator:
          • Tahseen Mozaffar, MD
        • Contact:
      • San Francisco, California, United States, 94158
        • Recruiting
        • University of California, San Francisco Benioff Children's Hospital - Accepting Young Adult and Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Susan Kim, MD, MMSc
    • Colorado
      • Aurora, Colorado, United States, 80046
        • Recruiting
        • Children's Hospital Colorado - Accepting Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Dr. Kentaro Yomogida, MD
    • Florida
      • Jacksonville, Florida, United States, 32224
        • Recruiting
        • Mayo Clinic Florida - Accepting Adult Patients
        • Contact:
      • St. Petersburg, Florida, United States, 33701
        • Recruiting
        • Johns Hopkins All Children's Hospital - Accepting Juvenile Patients
        • Principal Investigator:
          • Natalie Booth, DO
        • Contact:
    • Georgia
      • Atlanta, Georgia, United States, 30032
        • Recruiting
        • Emory University - Accepting Adult Patients
        • Contact:
        • Principal Investigator:
          • Prateek Chandrashekar Gandiga, MD, FACP
        • Contact:
      • Atlanta, Georgia, United States, 30029
        • Recruiting
        • Children's Healthcare of Atlanta - Accepting Juvenile Patients
        • Principal Investigator:
          • Shanmuganathan Chandrakasan, MD
        • Contact:
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Recruiting
        • Northwestern Memorial Hospital - Accepting Adult Patients
        • Principal Investigator:
          • Dr. George Georges, MD
        • Contact:
      • Chicago, Illinois, United States, 60637
      • Chicago, Illinois, United States, 60611
        • Recruiting
        • Ann & Robert H. Lurie Children's Hospital of Chicago - Accepting Young Adult and Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Pooja N. Patel, DO
    • Kansas
      • Kansas City, Kansas, United States, 66160
        • Recruiting
        • University of Kansas Medical Center - Accepting Adult Patients
        • Contact:
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • Not yet recruiting
        • National Institutes of Health - Accepting Adult and Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Andrew Mammen, M.D., Ph.D.
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
        • Recruiting
        • Boston Children's Hospital - Accepting Young Adults and Juvenile Patients
        • Principal Investigator:
          • Susan Prockop, MD
        • Contact:
    • Michigan
      • Ann Arbor, Michigan, United States, 48105
        • Recruiting
        • University of Michigan - Accepting Young Adult and Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Dr. Jennifer Agrusa, MD
    • Minnesota
      • Rochester, Minnesota, United States, 55902
        • Recruiting
        • Mayo Clinic - Accepting Adult Patients
        • Contact:
    • New York
      • New York, New York, United States, 10021
        • Recruiting
        • Hospital for Special Surgery - Accepting Adult and Juvenile Patients
        • Contact:
        • Principal Investigator:
          • David R. Fernandez, MD, PhD
      • New York, New York, United States, 10021
        • Recruiting
        • Memorial Sloan Kettering Cancer Center - Accepting Adult and Juvenile Patients
        • Principal Investigator:
          • Jae Park, MD
        • Contact:
      • The Bronx, New York, United States, 10467
        • Recruiting
        • Children's Hospital at Montefiore - Accepting Young Adult and Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Dr. Dawn Wahezi, MD, MS
    • North Carolina
      • Chapel Hill, North Carolina, United States, 27599
        • Recruiting
        • University of North Carolina at Chapel Hill - Accepting Adult Patients
        • Principal Investigator:
          • Saira Sheikh, MD
        • Contact:
      • Durham, North Carolina, United States, 27710
        • Recruiting
        • Duke University Medical Center - Accepting Young Adults and Juvenile Patients
        • Principal Investigator:
          • Kaveh Ardalan, MD, MS
        • Contact:
    • Oregon
      • Portland, Oregon, United States, 97239
        • Recruiting
        • Oregon Health & Science University - Accepting Adult Patients
        • Contact:
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Recruiting
        • Children's Hospital of Philadelphia - Accepting Young Adult and Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Dr. Caitlin Elgarten, MD, MSCE
      • Pittsburgh, Pennsylvania, United States, 15224
        • Not yet recruiting
        • UPMC Children's Hospital of Pittsburgh - Accepting Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Kathryn Torok, MD
      • Pittsburgh, Pennsylvania, United States, 15261
        • Recruiting
        • UPMC Arthritis and Autoimmunity Center - Accepting Adult Patients
        • Contact:
        • Principal Investigator:
          • Jeremy Tilstra, MD
    • Tennessee
      • Nashville, Tennessee, United States, 37232
        • Recruiting
        • Vanderbilt University Medical Center - Accepting Adult Patients
        • Contact:
    • Texas
      • Dallas, Texas, United States, 75390
        • Recruiting
        • University of Texas Southwestern Medical Center - Accepting Juvenile Patients
        • Principal Investigator:
          • Samuel John, MD
        • Contact:
      • Houston, Texas, United States, 77030
        • Recruiting
        • Houston Methodist Hospital - Accepting Adult Patients
        • Contact:
      • Houston, Texas, United States, 77030
        • Recruiting
        • University of Texas MD Anderson Cancer Center - Accepting Adult Patients
        • Principal Investigator:
          • Huifang (Linda) Lu, MD
        • Contact:
    • Utah
      • Salt Lake City, Utah, United States, 84113
        • Not yet recruiting
        • Primary Children's Hospital/University of Utah - Accepting Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Aimee Ogden Hersh, MD
    • Washington
      • Seattle, Washington, United States, 98105
        • Recruiting
        • Seattle Children's Research Institute - Accepting Juvenile Patients
        • Contact:
        • Principal Investigator:
          • Dr. Susan Shenoi, MD, MS
    • Wisconsin
      • Milwaukee, Wisconsin, United States, 53226
        • Not yet recruiting
        • Children's Wisconsin Pediatric Rheumatology -Accepting Young Adult and Juvenile Patients
        • Principal Investigator:
          • Sara Sabbagh, DO
        • Contact:
          • Erin Hammelev - Research Coordinator
          • Phone Number: 414-337-7064
          • Email: ehammele@mcw.edu

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Adult Cohorts

Inclusion Criteria:

  • Age ≥18 and ≤75
  • A clinical diagnosis of IIM, based on the 2017 The European League Against Rheumatism/American College of Rheumatology classification criteria
  • Diagnosis of DM, ASyS, or IMNM
  • Evidence of active disease, despite prior or current treatment with standard of care treatments, as defined by the presence of elevated creatine kinase (CK), DM rash, or active disease on muscle biopsy, magnetic resonance imaging (MRI), or electromyography
  • Presence of muscle weakness

Other protocol-defined criteria apply.

Exclusion Criteria:

  • Contraindication to leukapheresis
  • History of anaphylactic or severe systemic reaction to fludarabine, cyclophosphamide or any of their metabolites
  • Active infection requiring medical intervention at screening
  • Current symptoms of severe, progressive, or uncontrolled renal, hepatic, hematological, gastrointestinal, pulmonary, psychiatric, cardiac, neurological, or cerebral disease, including severe and uncontrolled infections, such as sepsis and opportunistic infections
  • Concomitant medical conditions that, in the opinion of the investigator, might place the subject at unacceptable risk for participation in this study, interfere with the assessment of the effects or safety of the investigational product or with the study procedures
  • Significant lung or cardiac impairment
  • Previous CAR T cell therapy
  • Prior solid organ (heart, liver, kidney, lung) transplant or hematopoietic cell transplant

Other protocol-defined criteria apply.

Juvenile Cohort

Inclusion Criteria:

  • Age ≥6 and ≤17 years at enrollment
  • A clinical diagnosis of IIM, based on the 2017 The European League Against Rheumatism/American College of Rheumatology classification criteria
  • Evidence of active disease, despite prior or current treatment with standard of care treatments, as defined by the presence of elevated muscle enzymes, DM rash, or active disease on muscle biopsy, magnetic resonance imaging (MRI), or electromyography

Other protocol-defined criteria apply.

Exclusion Criteria:

  • Contraindication to leukapheresis
  • History of anaphylactic or severe systemic reaction to fludarabine, cyclophosphamide or any of their metabolites
  • Active infection requiring medical intervention at screening
  • Current symptoms of severe, progressive, or uncontrolled renal, hepatic, hematological, gastrointestinal, pulmonary, psychiatric, cardiac, neurological, or cerebral disease, including severe and uncontrolled infections, such as sepsis and opportunistic infections.
  • Concomitant medical conditions that, in the opinion of the investigator, might place the subject at unacceptable risk for participation in this study, interfere with the assessment of the effects or safety of the investigational product or with the study procedures
  • Significant lung or cardiac impairment
  • Previous CAR T cell therapy
  • Prior solid organ (heart, liver, kidney, lung) transplant or hematopoietic cell transplant

Other protocol-defined criteria apply.

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: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: CABA-201 Phase 1/2

DM Cohort: Infusion of CABA-201 following preconditioning with fludarabine and cyclophosphamide in subjects with DM.

ASyS Cohort: Infusion of CABA-201 following preconditioning with fludarabine and cyclophosphamide in subjects with ASyS.

IMNM Cohort: Infusion of CABA-201 following preconditioning with fludarabine and cyclophosphamide in subjects with IMNM.

JIIM Cohort: Infusion of CABA-201 following preconditioning with fludarabine and cyclophosphamide in subjects with JIIM.
Biological: CABA-201 following preconditioning with fludarabine and cyclophosphamide
Single intravenous infusion of CABA-201 at a single dose level following preconditioning with fludarabine and cyclophosphamide
Other Names:
  • Rese-cel
  • Resecabtagene autoleucel
Experimental: CABA-201 Phase 2b - Sub-study 1
Infusion of CABA-201 following preconditioning with fludarabine and cyclophosphamide in subjects with DM and ASyS.
Biological: CABA-201 following preconditioning with fludarabine and cyclophosphamide
Single intravenous infusion of CABA-201 at a single dose level following preconditioning with fludarabine and cyclophosphamide
Other Names:
  • Rese-cel
  • Resecabtagene autoleucel
Experimental: CABA-201 Phase 2b - Sub-study 2
Infusion of CABA-201 following preconditioning with fludarabine and cyclophosphamide in subjects with IMNM.
Biological: CABA-201 following preconditioning with fludarabine and cyclophosphamide
Single intravenous infusion of CABA-201 at a single dose level following preconditioning with fludarabine and cyclophosphamide
Other Names:
  • Rese-cel
  • Resecabtagene autoleucel

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Phase 1/2: Incidence and severity of adverse events (AEs)
Time Frame: Up to 28 days after CABA-201 infusion
Incidence and severity of AEs
Up to 28 days after CABA-201 infusion
Phase 2b Sub-study 1: Proportion of DM & ASyS subjects achieving at least a moderate Total Improvement Score (TIS) without any immunomodulatory medications and no or low dose of steroids
Time Frame: Within 16 weeks
≥40 on the TIS, a composite measure ranging from 0 to 100, derived from six Core Set Measures, with higher scores indicating greater clinical improvement
Within 16 weeks
Phase 2b Sub-study 2: Proportion of subjects with IMNM achieving at least a minimal TIS without any immunomodulatory medications and no or low dose of steroids
Time Frame: Within 24 weeks
≥20 on the TIS, a composite measure ranging from 0 to 100, derived from six Core Set Measures, with higher scores indicating greater clinical improvement
Within 24 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of adverse events and laboratory abnormalities
Time Frame: Up to 156 weeks (Phase 1/2) and through 52 weeks (Sub-study 1 and 2)
Incidence and severity of AEs, including changes in laboratory values and vital signs
Up to 156 weeks (Phase 1/2) and through 52 weeks (Sub-study 1 and 2)
Pharmacodynamics (PD)
Time Frame: Up to 156 weeks (Phase 1/2) and through 52 weeks (Sub-study 1 and 2)
Levels of B cells in the blood
Up to 156 weeks (Phase 1/2) and through 52 weeks (Sub-study 1 and 2)
Pharmacokinetics (PK)
Time Frame: Up to 156 weeks (Phase 1/2) and through 52 weeks (Sub-study 1 and 2)
Levels of CABA-201-positive T cells in the blood
Up to 156 weeks (Phase 1/2) and through 52 weeks (Sub-study 1 and 2)
Change in disease-related biomarkers of muscle inflammation
Time Frame: Up to 156 weeks (Phase 1/2)
Levels of muscle enzymes (CK, LDH, AST, ALT, and aldolase) in serum
Up to 156 weeks (Phase 1/2)
Change in autoantibody-related biomarkers
Time Frame: Up to 156 weeks (Phase 1/2)
Levels of autoantibodies from the Myositis-Specific Autoantibody Panel (e.g., MDA-5, Jo-1, and HMGCR) in the serum
Up to 156 weeks (Phase 1/2)
Proportion of DM subjects achieving at least a moderate TIS without any immunomodulatory medications and no or low dose of steroids
Time Frame: Week 16 (Sub-study 1)
≥40 on the TIS, a composite measure ranging from 0 to 100, derived from six Core Set Measures, with higher scores indicating greater clinical improvement
Week 16 (Sub-study 1)
Mean change from baseline on the MMT-8 in subjects with DM and ASyS without any immunomodulatory medications and no or low dose of steroids
Time Frame: Week 16 (Sub-study 1)
MMT-8 measures muscle strength on a scale ranging from 0 to 150 points, where higher scores reflect greater muscle strength
Week 16 (Sub-study 1)
Proportion of DM and ASyS subjects achieving a major TIS response without any immunomodulatory medications and no or low dose of steroids
Time Frame: Week 16 (Sub-study 1)
≥60 on the TIS, a composite measure ranging from 0 to 100, derived from six Core Set Measures, with higher scores indicating greater clinical improvement
Week 16 (Sub-study 1)
Proportion of subjects with DM & ASyS achieving moderate TIS without any immunomodulatory medications on no or low dose of steroids
Time Frame: Week 52 (Sub-study 1)
≥40 on the TIS, a composite measure ranging from 0 to 100, derived from six Core Set Measures, with higher scores indicating greater clinical improvement
Week 52 (Sub-study 1)
Proportion of subjects with DM achieving moderate TIS without any immunomodulatory medications on no or low dose of steroids
Time Frame: Week 52 (Sub-study 1)
≥40 on the TIS, a composite measure ranging from 0 to 100, derived from six Core Set Measures, with higher scores indicating greater clinical improvement
Week 52 (Sub-study 1)
Mean change from baseline on the MMT-8 in subjects with IMNM without any immunomodulatory medications and no or low dose of steroids
Time Frame: Week 24 (Sub-study 2)
MMT-8 measures muscle strength on a scale ranging from 0 to 150 points, where higher scores reflect greater muscle strength
Week 24 (Sub-study 2)
Proportion of subjects with IMNM achieving at least minimal TIS response without immunomodulatory medications and no or low dose of steroids
Time Frame: Week 52 (Sub-study 2)
≥20 on the TIS, a composite measure ranging from 0 to 100, derived from six Core Set Measures, with higher scores indicating greater clinical improvement
Week 52 (Sub-study 2)

Collaborators and Investigators

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

Sponsor

Cabaletta Bio

Investigators

  • Study Chair: Medical Director, Cabaletta Bio

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)

December 20, 2023

Primary Completion (Estimated)

July 1, 2028

Study Completion (Estimated)

July 1, 2028

Study Registration Dates

First Submitted

November 16, 2023

First Submitted That Met QC Criteria

November 30, 2023

First Posted (Actual)

December 4, 2023

Study Record Updates

Last Update Posted (Actual)

May 14, 2026

Last Update Submitted That Met QC Criteria

May 12, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CAB-201-002

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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