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Active, Not Recruiting

NCT Number: NCT06282159

A Phase 2 Study to Evaluate DNTH103 in Adults With Generalized Myasthenia Gravis (MAGIC)

The purpose of this Phase 2 study is to evaluate the safety, tolerability, pharmacometrics, and efficacy of DNTH103 in participants with generalized myasthenia gravis (gMG).

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Myasthenia Gravis, Generalized Autoimmune Diseases Autoimmune Diseases of the Nervous System Immune System Diseases Myasthenia Gravis Neoplasms Neoplasms by Site Nervous System Diseases Nervous System Neoplasms Neurodegenerative Diseases Neuromuscular Diseases Neuromuscular Junction Diseases Paraneoplastic Syndromes Paraneoplastic Syndromes, Nervous System

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Clinical Study Site, San Miguel de Tucumán, Tucumán Province, Argentina

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About this study

The study includes the following periods:

  • Screening (up to 10 weeks)
  • Randomized, blinded, controlled treatment (RCT) period (13 weeks)
  • Open-label extension (OLE) period (optional) for eligible participants (104 weeks)
  • Safety follow-up (SFU) (40 weeks)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Must have given written informed consent before any study-related activities are carried out.
  • Adult males and females, 18 to 75 years of age (inclusive) at Screening.
  • Weight range between 40-120 kg at Screening.
  • Diagnosis of gMG by the following tests:

Acetylcholine receptor antibody (AChR Ab) positive, and

One of the following:

i. History of abnormal neuromuscular transmission test; ii. History of positive anticholinesterase test; iii. Clinical response to acetylcholinesterase inhibitors.

  • Myasthenia Gravis Foundation of America (MGFA) Class II-Iva
  • Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 6 or more
  • Vaccination against N. meningitidis with the quadrivalent meningococcal vaccine, and where available, meningococcal serotype B vaccine within 3 years prior to, or at the time of, initiating study drug.
  • Female participants must:

Be of non-childbearing potential, or if of childbearing potential, must agree not to donate ova, not to attempt to become pregnant and, if engaging in sexual intercourse with a male partner, must agree to use a highly effective method of contraception.

  • Male participants must be surgically sterile for at least 90 days prior to screening or agree not to donate sperm

Exclusion criteria

  • History or presence of significant medical/surgical condition including any acute illness or major surgery considered to be clinically significant
  • Prior history (at any time) of N. meningitidis infection.
  • Positive test results for active human immunodeficiency virus (HIV-1 or HIV-2), hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibodies during Screening.
  • Any thymic surgery/biopsy within 1 year of Screening.
  • Any known or untreated thymoma.
  • Any history of thymic carcinoma or thymic malignancy.
  • Concurrent or previous use of the following medication within the time periods specified below.
  • Rituximab within 6 months (180 days) prior to randomization (Day 1);
  • Intravenous immunoglobulin (IVIg) and plasma exchange (PLEX) within 4 weeks (28 days) prior to randomization (Day 1).
  • Participation in another clinical study of an investigational drug within 90 days or 5 half-lives of the investigational agent.

Treatment and study plan

Claseprubart

Drug

Day 1: IV loading dose Week 1 to Week 11: Claseprubart administered SC every 2 weeks

Other names: DNTH103

Placebo

Drug

Day 1: IV infusion of placebo Week 1 to Week 11: placebo administered SC every 2 weeks

Primary outcomes

  1. Incidence of Treatment-Emergent Adverse Events (TEAEs) and Treatment-Emergent Serious Adverse Events (SAEs)

    Time frame: Baseline (Day 1) to Week 13

    Number of participants with TEAEs and treatment-emergent SAEs will be reported.

Secondary outcomes

  1. Change from Baseline in Myasthenia Gravis Activities of Daily Living (MG-ADL) Scale Score

    Time frame: Baseline (Day 1) to Week 13

    The MG-ADL score is an 8-item patient reported outcome (PRO) instrument. The MG-ADL targets symptoms of disability across ocular, bulbar, respiratory, and axial symptoms. The item responses are scored from 0 to 3, and the total score of the MG-ADL is the sum of the 8 items and ranges from 0 to 24, with a higher score indicating more disability.

  2. Change from Baseline in Quantitative Myasthenia Gravis (QMG) Scale Score

    Time frame: Baseline (Day 1) to Week 13

    The QMG is a clinician-reported assessment to evaluate muscle strength. The QMG consists of 13 items that measure endurance or fatiguability, with each item having a possible score that ranges from 0 - 3. The total possible QMG scores range from 0 - 39, with a higher score indicating greater disease burden.

  3. Change from Baseline to Week 13 in Myasthenia Gravis Composite (MGC) Scale Score

    Time frame: Baseline (Day 1) to Week 13

    The MGC is a validated assessment tool for measuring clinical status of participants with MG. The range of total MGC score is 0 to 50, with higher scores indicating more severe disease. A clinically meaningful improvement is reflected by a 3-point improvement in MGC score. The MGC assesses 10 important functional areas most frequently affected by MG and the scales are weighted for clinical significance that incorporates patient-reported outcomes.

  4. Incidence of TEAEs and Treatment-Emergent SAEs

    Time frame: Through OLE completion, an average of 117 weeks

    Number of participants with TEAEs and treatment-emergent SAEs will be reported.

  5. Serum Concentrations of Claseprubart

    Time frame: Baseline (Day 1) through end of SFU, for a maximum of 197 weeks

    Blood samples will be collected for measurement of serum concentrations of claseprubart at various timepoints both pre- and post-dose.

  6. Change from Baseline in Complement Total Blood Test (CH50)

    Time frame: Baseline (Day 1) through end of SFU, for a maximum of 197 weeks

    Blood samples will be collected to determine changes in CH50 at various timepoints.

  7. Incidence and Titer of Antidrug Antibody (ADAs) Against Claseprubart

    Time frame: Baseline (Day 1) through end of SFU, for a maximum of 197 weeks

    Blood samples will be collected to measure ADA against claseprubart at various timepoints.

Sponsors and collaborators

Lead sponsor

Dianthus Therapeutics

Industry

Registry information

Official study title

A Phase 2, Randomized, Blinded, Placebo-Controlled, Study to Evaluate Safety, Tolerability, Pharmacometrics, and Efficacy of DNTH103 in Adults With Generalized Myasthenia Gravis (MAGIC)

Acronym: MAGIC

Important dates

Study start
2024
Primary completion
2025
Study completion
2028
First posted
Feb 28, 2024
Registry last updated
Jul 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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