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

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Cabaletta Bio Inc.

Participant type

Pediatric, Patients

Age range

0-17 years, 18-64 years

Gender

Male and Female

Therapeutic area

Diseases [C] - Immune System Diseases [C20]

Decision date (initial)

2026-04-30

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

Yes

External identifiers

EU CT number

2025-521145-24-01

ClinicalTrials.gov

NCT06154252

ISRCTN

ISRCTN75158615

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Efficacy, Pharmacogenetic, Safety, Therapy, Pharmacodynamic, Pharmacokinetic

To evaluate adverse events reported by subjects

Secondary objectives 6

1. To evaluate adverse events and laboratory abnormalities
2. To characterize the pharmacodynamics (PD)
3. To characterize the pharmacokinetics (PK)
4. To evaluate disease-related biomarkers of muscle inflammation
5. To evaluate autoantibody -related biomarkers
6. To evaluate efficacy Total Improvement Score (0 to 100, with higher scores indicating greater improvement) based on the Core Set Measures [Time Frame: Up to 156 Weeks]

Conditions and MedDRA coding

Active Idiopathic Inflammatory Myopathy including dermatomyositis, anti-synthetase syndrome, immune-mediated necrotizing myopathy or Juvenile Idiopathic Inflammatory Myopathy

Study design 1 period

Regulatory references

Scientific advice from competent authorities

Paul-Ehrlich-Institut, Swedish Medical Products Agency

Plan to share IPD

Yes

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 5

1. Age ≥6 to ≤75 years
2. A clinical diagnosis of IIM, based on the 2017 The European League Against Rheumatism/American College of Rheumatology classification criteria
3. Diagnosis of DM, ASyS, IMNM or JIIM based on the presence of serum myositis-specific antibodies
4. Evidence of active disease, despite prior or current treatment with standard of care treatments, as defined by the presence of elevated 12 of 40 creatine kinase (CK), DM rash, or active disease on muscle biopsy, magnetic resonance imaging (MRI), or electromyography
5. Presence of Muscle Weakness

Exclusion criteria 8

1. Contraindication to leukapheresis
2. History of anaphylactic or severe systemic reaction to fludarabine, cyclophosphamide or any of their metabolites
3. Active infection requiring medical intervention at screening
4. 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.
5. Significant lung or cardiac impairment
6. Previous CAR T cell therapy
7. Prior solid organ (heart, liver, kidney, lung) transplant or hematopoietic cell transplant
8. 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

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. Incidence and severity of AEs

Secondary endpoints 6

1. Incidence and severity of AEs, including changes in laboratory values and vital signs
2. Levels of B cells in the blood
3. Levels of CABA-201-positive T cells in the blood
4. Levels of muscle enzymes (CK, LDH, AST, ALT, and aldolase) in serum
5. Levels of autoantibodies from the Myositis-Specific Autoantibody Panel (e.g., MDA-5, Jo-1, and HMGCR) in the serum
6. Total Improvement Score (0 to 100, with higher scores indicating greater improvement) based on the Core Set Measures

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Auxiliary 6

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Cabaletta Bio Inc.

Sponsor organisation

Cabaletta Bio Inc.

Address

2929 Arch Street Suite 600

City

Philadelphia

Postcode

19104-2857

Country

United States

Scientific contact point

Organisation

Cabaletta Bio Inc.

Contact name

Cabaletta EU Regulatory

Public contact point

Organisation

Cabaletta Bio Inc.

Contact name

Cabaletta EU Regulatory

Third parties 16

Locations

3 EU/EEA countries · 6 investigational sites

By country

Investigational sites

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 149 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

1 submissions — initial application plus substantial / non-substantial modifications