Study to Evaluate Amifampridine Phosphate in Patients With MuSK-MG
Condition: Myasthenia Gravis, Generalized
MeSH terms: Myasthenia Gravis
Intervention: Amifampridine Phosphate; Placebo Oral Tablet
Intervention description: tablets equivalent to 10mg amifampridine, titrated to an efficacious and tolerable dose, 3 to 4 times a day; tablets matching amifampridine phosphate, 3 to 4 times a day
Intervention MeSH terms: Amifampridine
Phase: Phase 3
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 93.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No
Keywords: MuSK antibody positive

Summary:

      Efficacy and safety of amifampridine phosphate in improving the activities of daily living
      for patients with antibody positive MuSK myasthenia gravis.
    

Eligibility criteria:

        Inclusion Criteria:

          1. Willing and able to provide written informed consent after the nature of the study has
             been explained and before the start of any research-related procedures.

          2. Male or female ≥18 years of age.

          3. Positive serologic test for anti-MuSK antibodies or anti-AChR antibodies as confirmed
             at Screening or by previous antibody test, with report available.

          4. Confirmatory EMG or EMG report.

          5. Myasthenia Gravis Foundation of America (MGFA) Class II to IV at Screening.

          6. MG-ADL score of ≥6 at Screening, with more than 50% of this score attributed to
             non-ocular items.

          7. Patients receiving steroids or pyridostigmine should not have any modification of drug
             regimen during the month before Screening.

          8. Female patients of childbearing potential must have a negative pregnancy test (serum
             human chorionic gonadotropin [HCG] at screening); and must practice an effective,
             reliable contraceptive regimen during the study and for up to 30 days following
             discontinuation of treatment.

          9. Ability to participate in the study based on overall health of the patient and disease
             prognosis, as applicable, in the opinion of the Investigator; and able to comply with
             all requirements of the protocol, including completion of study questionnaires.

        Exclusion Criteria:

          1. Epilepsy and currently on medication.

          2. Concomitant use of medicinal products with a known potential to cause QTc
             prolongation.

          3. Patients with long QT syndromes.

          4. History of thymectomy within 12 months before Screening.

          5. An electrocardiogram (ECG) within 6 months before starting treatment that shows
             clinically significant abnormalities, in the opinion of the Investigator.

          6. Breastfeeding or pregnant at Screening or planning to become pregnant at any time
             during the study.

          7. Patients receiving immunomodulatory treatment (e.g. plasma exchange [PE], therapeutic
             plasma exchange [TPE], intravenous immunoglobulin G [IVIG]) should not have any
             treatment in the previous 4 weeks prior to Randomization or at any time during the
             study.

          8. Use of rituximab or other similar biologic medications for immunomodulation within 6
             months prior to Screening.

          9. Treatment with an investigational drug (other than amifampridine) or device within 30
             days before Screening or while participating in this study.

         10. Any medical condition that, in the opinion of the Investigator, might interfere with
             the patient's participation in the study, poses an added risk for the patient, or
             confound the assessment of the patient.

         11. History of drug allergy to any pyridine-containing substances or any amifampridine
             excipient(s).