Long Term Safety Study of Amifampridine Phosphate in MuSK-MG (Muscle Specific Tyrosine Kinase Myasthenia Gravis)

Phase 3

Terminated

• Conditions: Myasthenia Gravis, MuSK; AChR Myasthenia Gravis
• Interventions: Drug: Amifampridine Phosphate

• Registration Number: NCT03579966
• Lead Sponsor: Catalyst Pharmaceuticals, Inc.

Brief Summary

Evaluate the long-term safety of amifampridine phosphate in patients with MuSK antibody positive and AChR antibody positive myasthenia gravis.

Detailed Description

The Primary objective :

To characterize the long-term safety and tolerability of amifampridine phosphate in patients with MG

The Secondary Objective:

To assess the clinical efficacy of amifampridine phosphate over time in patients with MG based on change in Myasthenia Gravis Activities of Daily Living Score (MG-ADL)

This was a long-term extension study for subjects who participated in Protocol MSK-002 where the efficacy and safety of amifampridine was evaluated in subjects diagnosed with MuSK MG or AChR-MG. The optimal dose and schedule for amifampridine from the end of the Run-in Period from Study MSK-002 was initially used for each patient. The Investigator could adjust the dose of amifampridine during the course of the trial, in order to optimize neuromuscular benefit for the patient. Clinic visits for safety assessment and for evaluation of MG-ADL were made at Months 3, 6, 9, 12, 15, 21, 27, 33 and 39. Additional visits could occur at the discretion of the Investigator.

The Original protocol (12 Nov 2017) included analysis of MG-ADL change over time, however, Statistical Analysis Plan (SAP), dated 21 Feb 2023, removed the analysis of MG-ADL score change over time.

Study Timeline

• Study First Submitted: 2018-06-05
• Study Start: 2018-06-11
• Study First Submitted QC: 2018-07-05
• Study First Posted: 2018-07-09
• Primary Completion: 2022-08-05
• Study Completion: 2022-08-05
• Results First Submitted: 2024-03-12
• Status Verified: 2024-04
• Results First Submitted QC: 2024-04-15
• Last Update Submitted: 2024-04-15
• Results First Posted: 2024-05-07
• Last Update Posted: 2024-05-07

Recruitment & Eligibility

• Status: TERMINATED
• Sex: All
• Target Recruitment: 63

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
amifampridine phosphate	Amifampridine Phosphate	tablets equivalent to 10mg amifampridine, 3 to 4 times per day. Initially, the daily amifampridine doses were to be the doses that were determined at the end of the Run-in Period from the MSK-002 study. The usual range was from 30 to 80 mg total daily dose, given in three (3) or four (4) doses, with no single dose \> 20 mg

Primary Outcome Measures

Name	Time	Method
Number of Participants With Treatment-Emergent Adverse Events (Safety and Tolerability)	over 39 months	Evaluate the long-term safety and tolerability of amifampridine phosphate through the number of patients with treatment-emergent adverse events mapped to the Medical Dictionary for Regulatory Activities (MedDRA) SOCs and PTs. \[ Time Frame: over 39 months \] Descriptive statistics will be used to summarize study data.

Trial Locations

Locations (3)

Cleveland Clinic; 🇺🇸 Cleveland, Ohio, United States

Univerity of Pennsylvania; 🇺🇸 Philadelphia, Pennsylvania, United States

Department of Neuroimmunology and Neuromuscular Diseases Carlo Besta Neurological Institute Via Celoria; 🇮🇹 Milan, Italy