ClinicalTrials.gov record NCT06154252

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

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Aug 22, 2026

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

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
PhasePhase 2/3A study that tests whether a treatment works while continuing to check safety, in a larger group than a phase 2 study alone. It combines the aims of phase 2 and phase 3 in one protocol.
Age6 years old to 75 years old
SexAll
LocationUnited Kingdom, United States
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This open-label interventional study evaluates a single intravenous infusion of CABA-201 given after preconditioning with fludarabine and cyclophosphamide in people with active idiopathic inflammatory myopathies. It includes adult and juvenile cohorts and has phase 1/2 and phase 2b sub-studies. The study measures safety and clinical response using standard myositis outcome scores and laboratory markers.

What it is studying. The study is testing whether one dose of CABA-201 (autologous CD19-specific CAR T cells), given after preconditioning with fludarabine and cyclophosphamide, is safe and produces measurable clinical and biological responses in people with active forms of idiopathic inflammatory myopathy (including dermatomyositis, anti-synthetase syndrome, immune-mediated necrotizing myopathy, and juvenile forms).

What the researchers hope to learn. Scientific goals are to evaluate safety (incidence and severity of adverse events), to measure clinical responses using the Total Improvement Score (TIS) and muscle-strength tests, and to study biological effects such as blood B‑cell levels, presence of CABA-201-positive T cells, and changes in muscle inflammation biomarkers and autoantibodies.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

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

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Biological
  • CABA-201 following preconditioning with fludarabine and cyclophosphamide

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

  • Adult Cohorts
  • 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
  • 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.
  • 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 description and what participation involves

The study's detailed description, as published on ClinicalTrials.gov.

Detailed description from the registry

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.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Participants will undergo leukapheresis (blood cell collection) to make their autologous CABA-201 cells, receive short-course preconditioning with fludarabine and cyclophosphamide, then a single intravenous infusion of CABA-201. After infusion there are regular follow-up visits for safety monitoring, blood tests to measure B cells and CABA-201–positive T cells and disease biomarkers, and clinical assessments of muscle strength and disease activity. Some assessments used to document active disease (for eligibility or follow-up) may include muscle enzyme tests, MRI, EMG, or muscle biopsy if needed. Follow-up periods vary by group, with some participants followed for up to 156 weeks and others through 52 weeks.

How the study is structured. Interventional, open-label, non-randomized, single-group study with phase 1/2 and phase 2b sub-studies. Participants receive preconditioning with fludarabine and cyclophosphamide followed by a single intravenous infusion of CABA-201, then are followed for safety and outcome measures (follow-up timeframes in the record include up to 156 weeks for some cohorts and through 52 weeks for sub-studies). There is no masking and no control/placebo group. The ClinicalTrials.gov record is inconsistent about the study phase: its structured phase field lists Phase 2 and Phase 3, while the official title and the study arms describe Phase 1/2 and Phase 2b sub-studies.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • The listed sites are in United Kingdom, United States. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on anti-synthetase syndrome

This trial is also listed on this site under dermatomyositis and polymyositis.

Clinical trials11 trials listed for anti-synthetase syndromeEvery trial the registry lists for anti-synthetase syndrome, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in anti-synthetase syndrome researchLatest monthly update: September 2026. Includes: Lung medicine pattern. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
Dec 20, 2023
Primary completion
July 2028 (estimated)
Study completion
July 2028 (estimated)
Target enrollment
74 participants (estimated)
Last updated on registry
Sep 17, 2026
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
Cabaletta Bio

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Participating sites (35)

  • University of California Irvine - Accepting Adult PatientsRecruiting

    Orange, California, 92868 · United States

  • University of California, San Francisco Benioff Children's Hospital - Accepting Young Adult and Juvenile PatientsRecruiting

    San Francisco, California, 94158 · United States

  • Children's Hospital Colorado - Accepting Juvenile PatientsRecruiting

    Aurora, Colorado, 80046 · United States

  • Mayo Clinic Florida - Accepting Adult PatientsRecruiting

    Jacksonville, Florida, 32224 · United States

  • Johns Hopkins All Children's Hospital - Accepting Juvenile PatientsRecruiting

    St. Petersburg, Florida, 33701 · United States

  • Children's Healthcare of Atlanta - Accepting Juvenile PatientsRecruiting

    Atlanta, Georgia, 30029 · United States

  • Emory University - Accepting Adult PatientsRecruiting

    Atlanta, Georgia, 30032 · United States

  • Ann & Robert H. Lurie Children's Hospital of Chicago - Accepting Young Adult and Juvenile PatientsRecruiting

    Chicago, Illinois, 60611 · United States

  • Northwestern Memorial Hospital - Accepting Adult PatientsRecruiting

    Chicago, Illinois, 60611 · United States

  • The University of Chicago Medical Center - Accepting Adult and Juvenile PatientsRecruiting

    Chicago, Illinois, 60637 · United States

Terms used on this page · explanations by MedicalUpdates.ai

Open-Label
No masking is used, so the assigned intervention is not deliberately hidden from participants or study staff.
standard of care
Treatment generally considered appropriate for a condition in a particular clinical setting. It can vary by patient, place and over time. In many studies the new treatment is added to, or compared with, standard of care.
biopsy
Removal of a small piece of tissue so it can be examined under a microscope. 'Biopsy-proven' or 'histologically confirmed' means the diagnosis was confirmed by examining tissue under a microscope.
magnetic resonance imaging
A scan that uses magnets and radio waves, not X-rays, to make detailed pictures of the inside of the body. Some implants and metal objects mean a person cannot have one.
Contraindication
A reason a particular test or treatment should not be used for a person, for example a metal implant that rules out an MRI scan.
at screening
The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
investigational product
A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
CAR T
A treatment in which a person's own immune cells (T cells) are collected, modified in a laboratory to recognise a target, and returned to the body.
Cohort
A group of people who share a characteristic, such as a diagnosis, and are studied together. 'Prospective' means they are followed forward from enrolment; 'retrospective' means existing records are reviewed.
enrollment
The number of participants a study plans to include, or has included. 'Estimated' means the planned number; 'actual' means the number who joined.
Inclusion Criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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