MuSK Myasthenia GravisPhase 1NCT05451212
Open-label Study to Evaluate the Safety of Various Dosing Regimens of MuSK-CAART for MuSK Myasthenia Gravis
A Phase 1 study testing MuSK-CAART in people with MuSK Myasthenia Gravis, run by Cabaletta Bio at 5 sites in United States.
Trial summary
Muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG) is a rare but potentially severe disease, in which patients develop pathogenic autoantibodies that specifically target the MuSK protein in the neuromuscular junction. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- MuSK Myasthenia Gravis
- What is being tested?
- MuSK-CAART
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 7 participants
- Where
- 5 sitesUnited States
- Study dates
- 23 Nov 2022to 24 Jul 2025
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Confirmed diagnosis of MuSK-type MG with at least 1 prior positive anti-MuSK antibody test.
- History of a negative anti-AChR (acetylcholine receptor) antibody test.
- Positive anti-MuSK antibody test at screening
- MG severity Class I to IVa on the MGFA (Myasthenia Gravis Foundation of America) Clinical Classification
Who cannot join
- Rituximab in the last 12 months.
- Prednisone > 0.25mg/kg/day [in Part A]
- Other autoimmune disorder requiring immunosuppressive therapies.
- Investigational treatment for MG in the past 12 weeks.
- Absolute lymphocyte count < 500/µL at screening.
Trial locations and contacts
5 sites in 1 country.
5 sites in 1 country
United States5 sites
Houston Methodist Hospital
Houston, Texas, 77030
University of Kansas Medical Center
Kansas City, Kansas, 66160
UC Irvine, Department of Neurology
Orange, California, 92868
Oregon Health & Science University (OHSU)
Portland, Oregon, 97239
UC Davis, Department of Neurology
Sacramento, California, 95817
About this study
Official title: A Phase 1, Open-label, Safety and Dose-finding Study of Autologous Muscle-specific Tyrosine Kinase Chimeric Autoantibody Receptor T Cells (MuSK-CAART) in Subjects With Anti-MuSK-antibody-positive Myasthenia Gravis
Muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG) is a rare but potentially severe disease, in which patients develop pathogenic autoantibodies that specifically target the MuSK protein in the neuromuscular junction. This phase 1 study is being conducted to evaluate the safety of various dosing regimens of an investigational cell therapy, MuSK-CAART, that can be given to patients with anti-MuSK antibody positive Myasthenia Gravis (MuSK MG), who have active disease. Various dosing regimens of MuSK-CAART alone, in combination with cyclophosphamide (CY), and in combination with CY and fludarabine (FLU) will be evaluated. Treatment with MuSK-CAART may potentially lead to complete and durable remission of disease.
- Conditions
- MuSK Myasthenia Gravis
- Being tested
- MuSK-CAART
- Keywords
- CAAR-T (Chimeric Autoantibody Receptor T Cells) Therapy, CAR-T (Chimeric Antigen Receptor T Cells) Therapy, Cell Therapy, Autoimmune Disease, Autoimmunity, Immunotherapy, Adoptive, Immune System Diseases, Myasthenia Gravis (MG), Muscle-specific tyrosine kinase (MuSK), Muscle Weakness, Neuromuscular Diseases, Musculoskeletal Diseases
- Medical subject headings
- Myasthenia Gravis, Autoimmune Diseases, Immune System Diseases, Muscle Weakness, Neuromuscular Diseases, Musculoskeletal Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MuSK-CAARTBiological
Intravenous infusion of MuSK-CAART at different doses. Subjects may also receive MuSK-CAART following pre-treatment with CY, or CY plus FLU.
| Study group | Role | What they receive |
|---|---|---|
| MuSK-CAART | Experimental | Cohort A: Infusion of MuSK-CAART at various dose levels with or without pre-treatment (6 groups planned).
Cohort B: Infusion of MuSK-CAART at the dose regimen selected from Part A. Receives: Biological: MuSK-CAART |
What is being measured
The primary outcome is the main question the study is designed to answer.
Adverse events
Incidence of adverse events (AEs), including dose-limiting toxicities (DLTs) and AEs that are related to MuSK-CAART.
Measured: 3 months
Secondary outcomes (4)
Total MuSK-CAART positive cells
Total MuSK-CAART positive cells for each manufacturing run.
Measured: Baseline
Percent of CAAR-transduced cells
Percent of total cells for infusion that are CAAR (Chimeric Autoantibody Receptor)-transduced cells.
Measured: Baseline
Cellular kinetics profile of MuSK-CAART
Cellular kinetics profile of MuSK-CAART after infusion.
Measured: Up to 36 months
Change in MuSK autoantibody titer
Change in MuSK autoantibody titer compared to pre-infusion visit by clinically validated assay.
Measured: Up to 36 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Jul 2022
- Study start23 Nov 2022
- Primary completion24 Jul 2025
- Study completion24 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for MuSK Myasthenia GravisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 7 participants (actual)
Sponsor and investigators
- Lead sponsor
- Cabaletta Bio
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study chair, Cabaletta Bio
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05451212
- Sponsor's protocol ID
- CAB-MuSK-101
- Status last verified
- Nov 2025
- First submitted
- 30 Jun 2022
- Last updated
- 10 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1, Open-label, Safety and Dose-finding Study of Autologous Muscle-specific Tyrosine Kinase Chimeric Autoantibody Receptor T Cells (MuSK-CAART) in Subjects With Anti-MuSK-antibody-positive Myasthenia Gravis
- ClinicalTrials.gov ID
- NCT05451212
- Acronym / sponsor ID
- CAB-MuSK-101
- Conditions
- MuSK Myasthenia Gravis
- Keywords
- CAAR-T (Chimeric Autoantibody Receptor T Cells) Therapy, CAR-T (Chimeric Antigen Receptor T Cells) Therapy, Cell Therapy, Autoimmune Disease, Autoimmunity, Immunotherapy, Adoptive, Immune System Diseases, Myasthenia Gravis (MG)
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 7 participants (actual)
- Lead sponsor
- Cabaletta BioIndustry (pharma, biotech, devices)
- Study start
- 23 Nov 2022 (actual)
- Primary completion
- 24 Jul 2025 (actual)
- Study completion
- 24 Jul 2025 (actual)
- First posted
- 11 Jul 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG) is a rare but potentially severe disease, in which patients develop pathogenic autoantibodies that specifically target the MuSK protein in the neuromuscular junction. This phase 1 study is being conducted to evaluate the safety of various dosing regimens of an investigational cell therapy, MuSK-CAART, that can be given to patients with anti-MuSK antibody positive Myasthenia Gravis (MuSK MG), who have active disease. Various dosing regimens of MuSK-CAART alone, in combination with cyclophosphamide (CY), and in combination with CY and fludarabine (FLU) will be evaluated. Treatment with MuSK-CAART may potentially lead to complete and durable remission of disease.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| MuSK-CAART | Experimental | Biological: MuSK-CAARTCohort A: Infusion of MuSK-CAART at various dose levels with or without pre-treatment (6 groups planned). Cohort B: Infusion of MuSK-CAART at the dose regimen selected from Part A. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Confirmed diagnosis of MuSK-type MG with at least 1 prior positive anti-MuSK antibody test.
- History of a negative anti-AChR (acetylcholine receptor) antibody test.
- Positive anti-MuSK antibody test at screening
- MG severity Class I to IVa on the MGFA (Myasthenia Gravis Foundation of America) Clinical Classification
Key exclusion criteria (5 listed)
- Rituximab in the last 12 months.
- Prednisone > 0.25mg/kg/day [in Part A]
- Other autoimmune disorder requiring immunosuppressive therapies.
- Investigational treatment for MG in the past 12 weeks.
- Absolute lymphocyte count < 500/µL at screening.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MuSK-CAARTIntravenous infusion of MuSK-CAART at different doses. Subjects may also receive MuSK-CAART following pre-treatment with CY, or CY plus FLU. | Biological | MuSK-CAART |
Primary outcome
Adverse events
Time frame: 3 months
Incidence of adverse events (AEs), including dose-limiting toxicities (DLTs) and AEs that are related to MuSK-CAART.
4 secondary outcomes
Total MuSK-CAART positive cells
Time frame: Baseline
Percent of CAAR-transduced cells
Time frame: Baseline
Cellular kinetics profile of MuSK-CAART
Time frame: Up to 36 months
Change in MuSK autoantibody titer
Time frame: Up to 36 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Nov 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Medical Director study chair
Cabaletta Bio
5 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing MuSK-CAART in people with MuSK Myasthenia Gravis, run by Cabaletta Bio at 5 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 10 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 5 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Adverse events (time frame: 3 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Nov 2025; AzTrials last refreshed its copy on 6 Nov 2026.