Clinical trial Recruiting at 150 sites Phase 3 Interventional Ages 18 and up

New oral cladribine formulation for treating generalized myasthenia gravis

Official title: A Phase 3, Randomized, Double-Blind, Placebo-Controlled, 3-Arm, 3-Period Study to Assess the Efficacy and Safety of a New Formulation of Oral Cladribine Compared With Placebo in Participants With Generalized Myasthenia Gravis (MyClad)

Run by Merck Healthcare KGaA, Darmstadt, Germany, an affiliate of Merck KGaA, Darmstadt, Germany · NCT06463587 · Data updated 2026-11-12

This study is testing a new pill for people with generalized myasthenia gravis to see if it helps them feel better compared to a sugar pill.

Quick facts

PhasePhase 3
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment264 (estimated)
SponsorMerck Healthcare KGaA, Darmstadt, Germany, an affiliate of Merck KGaA, Darmstadt, Germany
Industry-sponsored
Drugs / interventionseculizumab, rozanolixizumab, ravulizumab, nipocalimab, methotrexate, cyclophosphamide, prednisone
Locations154 sites (Phoenix, Arizona and 153 other locations)
StatusRecruiting
StartedJune 25, 2024
Main results expectedAugust 23, 2028
Study endsNovember 12, 2030
Registry record updatedOctober 21, 2026
Trial IDNCT06463587 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates include adults aged 18 and older diagnosed with generalized myasthenia gravis, particularly those with specific antibody profiles.

Probably not a fit

Patients with mild forms of myasthenia gravis or those not meeting the inclusion criteria may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This clinical trial evaluates the efficacy and safety of a new formulation of oral cladribine in patients with generalized myasthenia gravis (gMG) compared to a placebo. The study is structured into three periods: a double-blind placebo-controlled pivotal period, a blinded extension, and a retreatment period. It aims to assess not only the immediate effects of the treatment but also its long-term safety and the pharmacokinetics of the new formulation. Participants will be monitored for sustained efficacy and the need for retreatment over time.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the management of generalized myasthenia gravis, offering patients a new oral therapy option.

How similar studies have gone: Previous studies have shown promise with similar treatments for myasthenia gravis, indicating potential for success with this new formulation.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Adults of ≥ 18 years of age at the time of signing the informed consent.
* Diagnosis of Myasthenia Gravis with generalized muscle weakness, meeting clinical criteria for Myasthenia Gravis Foundation of America Class II to IVa classification.

  * In participants positive for Acetylcholine receptor antibody (anti-AChR) or muscle-specific kinase antibody(anti-MuSK)
  * In participants that are autoantibody seronegative i.e. not positive for anti-AChR and anti-MuSK antibodies and participants who are positive for anti-low-density lipoprotein receptor-related protein 4 antibodies (anti-LRP4)
* Has a Screening and Baseline MG-ADL score more than or equal to (\>=) 6 with \>= 50 percentage (%) of the total score due to non-ocular symptoms. Screening and Baseline MG-ADL scores must be stable. The difference between the Screening and Baseline scores should not be more than 2 and there should be no reported MG exacerbation during the Screening period
* If treated with oral corticosteroids: should be on a stable daily dose for at least 3 months prior to and during screening. In such case, the daily dose of oral steroids should not exceed 20 milligrams(mg)/day for prednisone/ prednisolone, 16 mg/day for methylprednisolone, 3 mg/day for dexamethasone, or 80 mg for hydrocortisone or equivalent doses for other corticosteroids.
* If treated with acetylcholinesterase inhibitor should be on a stable daily dose (pyridostigmine dose ≤ 480 mg/day or neostigmine ≤ 300 mg/day) for at least 3 months prior to and during screening
* Have a body weight \>= 40 kilograms
* Other protocol defined inclusion criteria could apply

Exclusion Criteria:

* Immunologic disorder other than MG or any other condition requiring chronic oral, intravenous, intramuscular, or intraarticular corticosteroid therapy. Well-controlled thyroid disease, as per the Treating Investigator or the participants regular treating physician recorded in the source documents, is not exclusionary
* Molecularly characterized or suspected congenital myasthenic syndrome, Lambert-Eaton myasthenic syndrome, inherited myopathy, muscular dystrophy, acquired myopathy or any other neurologic or systematic disease that mimics MG muscular weakness
* Active, clinically significant viral, bacterial, or fungal infection, including brain MRI or chest X-ray findings consistent with signs of infection such as PML or TB, or any major episode of infection requiring hospitalization or treatment with parenteral anti-infectives within 8 weeks prior or during Screening, or completion of oral anti-infectives within 8 weeks prior or during Screening. Vaginal candidiasis, onychomycosis, and genital or oral herpes simplex virus considered by the Investigator to be sufficiently controlled would not be exclusionary
* Has a history of or current diagnosis of active tuberculosis (TB) or is currently undergoing treatment for latent TB infection or has an untreated latent TB infection as determined by documented results within 3 months of the Screening Visit of a positive TB skin test .
* Active malignancy, or history of cancer or signs of malignancy in any Screening assessment
* Treatment with nonsteroidal immunosuppressants, used in gMG, such as azathioprine, mycophenolate mofetil, methotrexate, cyclosporine, cyclophosphamide, tacrolimus within 4 weeks prior to randomization
* Treatment with FcRn or complement inhibitors (such as eculizumab, rozanolixizumab efgartigimod, ravulizumab, zilucoplan or nipocalimab) within 8 weeks prior to randomization
* History of thymectomy within 6 months prior to Screening.
* History of generalized seizures (except for history of febrile seizures during the participant's childhood).
* Negative or indeterminate for Varicella Zoster Virus antibodies at screening
* History of myasthenic crisis in the last 12 months prior to and during screening
* History of recurrent infections (that is 3 or more infections per year documented in available source data) within the last 2 years
* Discontinuation of treatment with any non-steroidal immunosuppressants used in gMG, such as azathioprine, mycophenolate mofetil, methotrexate, cyclosporine, cyclophosphamide, tacrolimus within the last 6 months prior to Screening
* If treated with non-steroidal immunosuppressants for gMG, the dose at Screening higher than 50 mg/day for azathioprine, 500 mg/day for mycophenolate mofetil, 1 mg/day for tacrolimus, 50 mg/day for cyclosporine, 25 mg/day for cyclophosphamide, or 7.5 mg/week for methotrexate
* Participation in clinical study of any investigational drug within 6 months, or 5 half-lives of the investigational drug used in the previous clinical study prior to randomization, whichever is longer. However, participants with any prior exposure to cladribine may not enter the study regardless of timing of exposure
* Other protocol defined exclusion criteria could apply

Where it's running

  • Arizona Neuroscience Research, LLC
    Phoenix, Arizona, United States
    Recruiting
  • University of Connecticut Health Center - Department of Medicine
    Farmington, Connecticut, United States
    Recruiting
  • The George Washington University Medical Faculty Associates Foggy Bottom South Pavilion
    Washington D.C., District of Columbia, United States
    Recruiting
  • Neurology of Central Florida Research Center, LLC
    Altamonte Springs, Florida, United States
    Recruiting
  • SFM Clinical Research, LLC
    Boca Raton, Florida, United States
    Recruiting
  • University of Florida Health Science Center - 300120311
    Jacksonville, Florida, United States
    Recruiting
Show 44 more locations
  • Neurology Associates, P. A.
    Maitland, Florida, United States
    Recruiting
  • University of South Florida - PARENT - PARENT
    Tampa, Florida, United States
    Recruiting
  • University of Kansas Medical Center Research Institute, Inc. - 3901 Rainbow (MAIN)
    Kansas City, Kansas, United States
    Recruiting
  • UNC Hospitals - PARENT
    Chapel Hill, North Carolina, United States
    Recruiting
  • Atrium Health Wake Forest Baptist
    Winston-Salem, North Carolina, United States
    Recruiting
  • Miami Valley Hospital South
    Centerville, Ohio, United States
    Recruiting
  • University of Cincinnati
    Cincinnati, Ohio, United States
    Recruiting
  • Clinical Trials of South Carolina - Charleston
    Charleston, South Carolina, United States
    Recruiting
  • Erlanger Health, Inc. - 1123255
    Chattanooga, Tennessee, United States
    Recruiting
  • Baylor Scott & White Research Institute - Baylor Scott & White Research Institute
    Dallas, Texas, United States
    Recruiting
  • ANESC Research
    El Paso, Texas, United States
    Recruiting
  • Baylor Scott & White Neurology - McKinney
    McKinney, Texas, United States
    Recruiting
  • The University of Vermont Medical Center
    Burlington, Vermont, United States
    Recruiting
  • BCN Research
    Greenfield, Wisconsin, United States
    Recruiting
  • Expertia S.A- Mautalen Salud e Investigación
    Ciudad Autonoma Buenos Aires, Argentina
    Recruiting
  • Instituto de Investigaciones Neurologicas Raul Carrea, FLENI - de Investigaciones Clinicas del área de Cardiología y enfermedades metabólicas asociadas
    Ciudad Autonoma Buenos Aires, Argentina
    Recruiting
  • Instituto de Investigaciones Metabolicas (IDIM)
    Ciudad Autonoma Buenos Aires, Argentina
    Recruiting
  • Hospital Cordoba
    Córdoba, Argentina
    Recruiting
  • Fundacion Rosarina de Neurorehabilitacion
    Rosario, Argentina
    Recruiting
  • INECO Neurociencias Oroño
    Rosario, Argentina
    Recruiting
  • CER San Juan Centro Polivalente de Asistencia e Inv. Clinica
    San Juan, Argentina
    Recruiting
  • Centro de Investigaciones Medicas Tucuman
    San Miguel de Tucumán, Argentina
    Recruiting
  • Brain and Mind Research Institute
    Camperdown, New South Wales, Australia
    Recruiting
  • Sunshine Coast University Hospital
    Birtinya, Queensland, Australia
    Recruiting
  • Princess Alexandra Hospital - PARENT
    South Brisbane, Queensland, Australia
    Recruiting
  • John Hunter Hospital - PARENT
    City of Burnside, South Australia, Australia
    Recruiting
  • Box Hill Hospital - PARENT
    Box Hill, Victoria, Australia
    Recruiting
  • Gold Coast University Hospital - PARENT
    Southport, Australia
    Recruiting
  • UZ Leuven
    Leuven, Belgium
    Recruiting
  • C. H. R. de la Citadelle - Account 1
    Liège, Belgium
    Recruiting
  • Medical Center Hera - branch Montana
    Montana, Bulgaria
    Recruiting
  • UMHAT 'Dr. Georgi Stranski', EAD
    Pleven, Bulgaria
    Recruiting
  • UMHAT "Sv. Georgi", EAD
    Plovdiv, Bulgaria
    Recruiting
  • MHATNP "Sv.Naum", EAD - Third Neurology Clinic
    Sofia, Bulgaria
    Recruiting
  • UMHATEM 'N.I. Pirogov', EAD
    Sofia, Bulgaria
    Recruiting
  • Burnaby Hospital - Fraser Health Multiple Sclerosis Clinic
    Burnaby, British Columbia, Canada
    Recruiting
  • The First Affiliated Hospital of Bengbu Medical College
    Anhui Sheng, Anhui, China
    Recruiting
  • Xuanwu Hospital Capital Medical University
    Beijing, Beijing Municipality, China
    Recruiting
  • Peking Union Medical College Hospital
    Beijing, Beijing Municipality, China
    Recruiting
  • The First Affiliated Hospital of Guangzhou University of Chinese Medicine - 300164595
    Guangzhou, Guangdong, China
    Recruiting
  • Affiliated Hospital of Zunyi Medical University
    Zunyi, Guizhou, China
    Recruiting
  • Shijiazhuang People's Hospital
    Shijiazhuang, Hebei, China
    Recruiting
  • Henan Provincial People's Hospital
    Zhengzhou, Henan, China
    Recruiting
  • Xiangya Hospital, Central South University
    Changsha, Hu'nan, China
    Recruiting

+104 more sites. See ClinicalTrials.gov for the full list.

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.