A Phase 3 interventional study of Claseprubart and Placebo in Myasthenia Gravis, Generalized, sponsored by Dianthus Therapeutics. Recruiting at 12 sites in 3 countries. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by Dianthus Therapeutics · Phase 3, Interventional, and Treatment
The purpose of this Phase 3 study is to demonstrate the efficacy, safety, and tolerability of claseprubart in participants with generalized myasthenia gravis (gMG).
The study includes the following periods:
330 studies on the registry are indexed under Myasthenia Gravis; 144 are open to participants now.
This study's planned enrollment of 195 is above the median of 44 across 217 interventional studies indexed under Myasthenia Gravis.
Browse Myasthenia Gravis studies →Dianthus Therapeutics is the lead sponsor of 4 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Diagnosis of gMG by the following tests:
i. History of abnormal neuromuscular transmission test; ii. History of positive anticholinesterase test; iii. Clinical response to acetylcholinesterase inhibitors.
Exclusion Criteria:
Concurrent or previous use of the following medication within the time periods specified below.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Intravenous (IV) infusion of Placebo on Day 1 followed by subcutaneous (SC) injections of Placebo every 2 weeks (Q2W) starting at Week 1 (Day 8).
Drug: Placebo · Combination Product: Placebo
IV loading dose of claseprubart on Day 1 followed by SC injections of claseprubart Q2W starting at Week 1 (Day 8).
Drug: Claseprubart · Combination Product: Claseprubart
IV loading dose of claseprubart on Day 1 followed by SC injections of claseprubart or Placebo Q2W starting at Week 1 (Day 8), with doses alternating between claseprubart and placebo.
Drug: Claseprubart · Combination Product: Claseprubart · Combination Product: Placebo
IV loading dose on Day 1
Also known as: DNTH103
IV infusion on Day 1
Prefilled syringe containing claseprubart for SC administration
Prefilled syringe containing placebo for SC administration
Change from Baseline to Week 17 in Myasthenia Gravis Activities of Daily Living (MG-ADL) Scale Score
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.
Time frame: Baseline (Day 1) to Week 17
Change from Baseline to Week 17 in Quantitative Myasthenia Gravis (QMG) Scale Score
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.
Time frame: Baseline (Day 1) to Week 17
Change from Baseline to Week 17 in Myasthenia Gravis Composite (MGC) Scale Score
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.
Time frame: Baseline (Day 1) to Week 17
Proportion of Participants with Greater Than or Equal to (≥) a 5-point Reduction in MG-ADL Scale Score at Week 17 Compared to Baseline
Time frame: Baseline (Day 1) to Week 17
Proportion of Participants Who Reach Minimal Symptom Expression (MSE), Defined as MG-ADL 0 or 1 at Week 17, Without Use of Rescue Therapy
Time frame: Baseline (Day 1) to Week 17
Proportion of Participants with a ≥ 5-point Reduction in QMG Scale Score at Week 17 Compared to Baseline
Time frame: Baseline (Day 1) to Week 17
Incidence of Treatment-emergent Adverse Events (TEAEs) and Treatment-Emergent and Treatment-Emergent Serious Adverse Events (SAEs) in the RCT period, BEP, OLE, and Safety Follow-Up
Number of participants with TEAEs and treatment-emergent SAEs will be reported.
Time frame: Baseline (Day 1) through Safety Follow-Up period (up to approximately 161 weeks)
Serum Concentrations of Claseprubart
Blood samples will be collected for measurement of serum concentrations of claseprubart at various timepoints both pre- and post-dose.
Time frame: Baseline (Day 1) through Safety Follow-Up period (up to approximately 161 weeks)
Change from Baseline in Complement Total Blood Test (CH50) in Serum ex vivo
Blood samples will be collected to determine changes in CH50 at various timepoints.
Time frame: Baseline (Day 1) through Safety Follow-Up period (up to approximately 161 weeks)
Incidence of Antidrug Antibody (ADAs) Against Claseprubart in the RCT Period, BEP, OLE, and Safety Follow-Up
Blood samples will be collected to measure ADA against claseprubart at various timepoints.
Time frame: Baseline (Day 1) through Safety Follow-Up period (up to approximately 161 weeks)
Titer of ADAs Against Claseprubart in the RCT Period, BEP, OLE, and Safety Follow-Up
Blood samples will be collected to measure ADA against claseprubart at various timepoints.
Time frame: Baseline (Day 1) through Safety Follow-Up period (up to approximately 161 weeks)
Plan to share: No
No publications or documents are linked to this record.
Started Jun 2026 (actual). Primary completion is estimated for Dec 2028, 30 months after the start.
Of 43 industry-sponsored phase 3 interventional studies under Myasthenia Gravis, half reached primary completion within 27 months of starting (the median), counting those still running; a quarter within 19 and three quarters within 39. This study's planned 30 months is above that.
Counting every sponsor, half of 52 studies reached it within 30 months; a quarter within 20 and three quarters within 43.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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Studies of the drug tested here: Claseprubart
Dianthus Therapeutics