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Lambert-Eaton Myasthenic Syndrome

Myasthenic Syndromes, Congenital

Myasthenia Gravis

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Paraneoplastic Syndromes, Nervous System

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Lambert Eaton Myasthenic Syndrome

Congenital Myasthenic Syndromes

Laurent SERVAIS, MD, PhD

This is a retrospective study that follows the clinical evolution, the pregnancy and the post-partum perioad of female patients with Congenital Myasthenic Syndrome.

The aim of this study is to better understand the action of hormonal factors that are presumably incriminated for the fluctuation of the disease. The investigators would also like to better adress the issues of women with Congenital Myasthenic Syndrome, who desire a pregnancy : the possibility of decompensation, the problems that can arise during the course of the childbearing, the risk of foetal malformations.

Pregnancy Outcomes in Congenital Myasthenie Syndrome

Retrospective Study :Describe the Changes of the Disease in Many Cases Likely to Aggravate.

Assistance Publique - Hôpitaux de Paris

Institut de Myologie, France

Laurent SERVAIS MD, PhD

Reproductive Control Agents

Respiratory System Agents

All Drugs and Chemicals

Albuterol

Bronchodilator Agents

Anti-Asthmatic Agents

Tocolytic Agents

Adrenergic Agents

Adrenergic beta-Agonists

Adrenergic Agonists

Neurotransmitter Agents

4 mg twice daily by mouth for adults. The dose for children 6 to 12 years is 2 mg two or three times daily; the dose for children 2 to 6 years is 0.1 mg/kg/day (maximum 2 mg) three times daily.

Andrew G Engel, MD

The study tests the notion that patients suffering from certain types of congenital myasthenic syndromes are benefitted by the use of Albuterol at doses used in clinical practice.

The aim of the proposal is to evaluate the effects of albuterol, an adrenergic agonist, in the treatment of congenital myasthenic syndromes (CMS). Over the past 2 decades I found that some CMS patients refractory to or worsened by cholinergic agonists, namely those suffering from defects in acetylcholinesterase (AChE) or Dok-7, respond to ephedrine, a medication used for over half-a-century in the treatment of autoimmune myasthenia gravis. After ephedrine became unavailable, I treated the same type of patients with albuterol in doses ranging from 4 mg daily to twice daily for adults; the dose for children 6 to 12 years is 2 mg two or three times daily; the dose for children 2 to 6 years is 0.1 mg/kg/day (maximum 2 mg) three times daily. Evaluation of the effects of the medications are based on the Table shown below.

Name:

Mayo Clinic no:

Date of this report: (dd/mm/yyyy):

Before taking Albuterol ER On Albuterol (date of this report)

* Current daily dose of albuterol:

Dates when started (d/m/year) Daily dose Distance in feet walked without stopping to rest Number of steps climbed without stopping to rest Difficult to sit up from lying on back\* Difficult to rise from sitting\* Difficult to speak or swallow\* Shortness of breath on exertion\* Shortness of breath at night\* Weakness of arm or hand muscles \* Weakness of leg or foot muscles\*

\*Rate as mild, moderate, severe Describe below any additional changes in your condition such as arm elevation time, number of deep knee bends before having to stop, or in activities of daily living relevant to the effects of the treatment. Also indicate any unwanted side effects of the medication. Continue on other side or separate page if necessary. Return this questionnaire to Dr. Andrew Engel (email:schaefer.cleo@mayo.edu) ,after treatment with albuterol for 1 month and then monthly thereafter, or mail to Dr. Andrew Engel, Department of Neurology, Mayo Clinic, Rochester, MN 55905.

Efficacy of Albuterol in the Treatment of Congenital Myasthenic Syndromes

The primary outcome measures pertain to evaluating the improvement in the patient's strength

Mayo Clinic

Eye Diseases

Nystagmus, Pathologic

Channel Blockers

Amifampridine

Potassium Channel Blockers

Dosage form: tablets containing the equivalent of 10 mg amifampridine per tablet.

Amifampridine Phosphate given based on Investigator assessment of optimal neuromuscular benefit. In adult patients \> 16 years of age, Doses ranged from 30 mg to 80 mg, divided into doses taken 3 to 4 times per day and in pediatric patients age \< 16 years the maximum daily dose was 60 mg/day. No single dose to exceed 20 mg.

Amifampridine Phosphate

Perry Shieh, MD, PhD

Primary:

The primary objective of this study under the original protocol was to provide neuromuscular specialists and neurologists access to amifampridine phosphate therapy for their patients with LEMS, CMS or downbeat nystagmus until the product became commercially available.

Secondary:

The secondary objective of this study under the original protocol was to provide additional long-term safety data on amifampridine phosphate in patients.

Primary The primary objective of this study after its fifth amendment was to provide access to amifampridine phosphate therapy to pediatric patients with LEMS, and pediatric and adult patients with CMS until the product became commercially available for these indications or development of the product for the indication was terminated.

Secondary:

The secondary objective of this study after its fifth amendment was to assess the long-term safety of amifampridine phosphate in pediatric patients with LEMS, and pediatric and adult patients with CMS.

This multicenter, expanded access study was designed to allow EAP-001 Investigators, neuromuscular specialists, and neurologists access to amifampridine phosphate therapy for their patients with LEMS, CMS, or downbeat nystagmus until such time the product became commercially available for these specific indications or development of the product for the indication was terminated. Given that these are chronic conditions, this study obtained some long-term safety data by evaluating Adverse Events, physical exams, vital signs, standard safety laboratory tests (chemistry, hematology, and urinalysis), pregnancy testing (if applicable) and abnormal ECG findings, where each of these data/measures were performed as part of a routine standard of care treatment provided by the Principal Investigator or the patient's personal physician(s) (i.e., could be performed by a different physician not involved in the treatment of neuromuscular disease).

Planned -100 sites in US and up to 200 patients. Actual- 50 sites activated and 200 patients enrolled.

Patients were seen at screening/baseline, Day 1 and at least once per year at the PIs discretion. With the COVID-19 Pandemic, telehealth visits were allowed and assessments that could be completed via remote telehealth visits were performed via phone or videoconference. Follow-up visits included Physical exams, vital signs, standard safety laboratory tests (chemistry, hematology, and urinalysis), pregnancy testing (if applicable) and ECGs.

Patients were titrated to an optimal individualized dose of amifampridine phosphate based on Principal Investigator assessment of optimal neuromuscular benefit. In patients already taking amifampridine base, amifampridine phosphate was started at an equivalent or lower dose of amifampridine phosphate, at the Principal Investigator's discretion. Therapeutic doses were to range from 10 to 80 mg, divided into doses taken two (2) to four (4) times per day, with a maximum single dose of 20 mg. For upward titration, amifampridine phosphate could be increased by 10 mg increments every four (4) to five (5) days to a maximum of 80 mg per day (ages \>16 years), and to a maximum of 60 mg (ages 2 to 16 years) based on optimal neuromuscular benefit and at the discretion of the Principal Investigator. If needed, titration could occur in 5 mg/dose and per day increments. Drug was shipped to the clinic for the first dose ( Day 1) and subsequent shipments were sent to the patients home by a specialty pharmacy.

In addition to amifampridine phosphate, patients received best supportive care (BSC) treatment as determined by the Principal Investigator using concomitant medications permitted by protocol, including selected oral immunosuppressant's (i.e., prednisone or other corticosteroids, azathioprine, mycophenolate) and peripherally acting cholinesterase inhibitors (e.g., pyridostigmine). Changes to BSC could be made at the Principal Investigator's discretion, as long as prohibited concomitant medications were not used.

Firdapse® was approved for adult patients with LEMS in November 2018 and approved for pediatric patients with LEMS ages 6 years and older in September 2022. The indications for CMS and DBN were not pursued.

Expanded Access Study Amifampridine Phosphate in Lambert-Eaton Myasthenic Syndrome (LEMS),Congenital Myasthenic Syndrome

An Open-Label, Expanded Access Protocol for Firdapse® (Amifampridine Phosphate; 3,4-Diaminopyridine Phosphate) Treatment in Pediatric Patients With Lambert-Eaton Myasthenic Syndrome (LEMS), and in Pediatric and Adult Patients With Congenital Myasthenic Syndromes (CMSs)

Catalyst Pharmaceuticals, Inc.

Gastrointestinal Agents

Bismuth subsalicylate

Participants receiving intravenous infusion of ARGX-119 once every other week

Participants receiving intravenous infusion of placebo once every other week

ARGX-119

Placebo

Sabine Coppieters, MD

The purpose of this study is to assess the safety and tolerability of ARGX-119 in adult participants with DOK7- Congenital Myasthenic Syndromes. The study will also assess how ARGX-119 is processed by the body (pharmacokinetics), how the immune system reacts to it (immunogenicity), and how it may improve the way patients feel and function.

After the screening period, eligible participants will be randomized in a 4:1 ratio to receive intravenous infusions of ARGX-119 or placebo during the treatment period. Participants will then enter the follow-up period. The full duration of the study is approximately 11 months.

A Phase 1b Study to Investigate Safety and Tolerability of ARGX-119 in Adult Participants With DOK7-Congenital Myasthenic Syndromes (CMS)

A Phase 1b, Double-Blinded, Randomized, Placebo-Controlled Study to Assess the Safety, Tolerability, Pharmacokinetics, Immunogenicity, and Efficacy of ARGX-119 in Adult Participants With DOK7-Congenital Myasthenic Syndromes

Minimum value: 0 (no disease severity); Maximum value: 39 (highest disease severity)

Minimum value: 0 (normal symptoms); Maximum value: 24 (most severe symptoms)

The participant records their response to each question on a 5-point Likert scale, with lower scores indicating poorer health (Minimum value: 0, Maximum value: 20)

argenx

The investigator will prescribe an initial dose of 3,4 diaminopyridine (DAP) by mouth based on the participant's weight. This initial dose may be modified later according to the participant's response to treatment.

3,4-Diaminopyridine

Ricardo Maselli, MD

Congenital myasthenia is a potentially lethal disorder, which, even with careful management, significantly impedes participation in normal daily functions. Currently approved therapies have had little impact on promoting a normal quality of life activity in these patients. The goal is to systematically examine the effect of 3,4-DAP on the natural course of this disease and to gain additional experience in titrating 3,4-DAP with other available therapies to maximize clinical function and development in this patient population.

The specific aim of this study is to evaluate the use of 3,4 Diaminopyridine (DAP) on selected patients proven by genetic or serum antibody testing to have Congenital Myasthenic Syndrome (CMS), prescribe 3,4 DAP, and then clinically evaluate the response.

The subject population will consist of selected patients proven by genetic testing, muscle biopsy or antibody testing to have CMS. Consideration for entry in our clinical study will require referral from a treating pediatrician or neurologist. Dr. Maselli will examine patients and deem which are appropriate for neurophysiologic examinations at the University of California, Davis Medical Center. In vitro neuromuscular recordings of anconeus muscle biopsy material (as well as standard light and electron morphologic analysis) or documentation of a genetic mutation associated with congenital myasthenia will be required in some patients to confirm the diagnosis of CMS.

If a participant decides to volunteer, and if the diagnosis of Congenital Myasthenic Syndrome (CMS) has not been established, the participant may need to undergo a muscle biopsy or a blood sampling for DNA testing. The investigators will obtain a blood test (serum chemistry) before participants start treatment and then once a year after the start of 3,4-DAP treatment. Participants will also have an electrocardiograph (EKG) before starting treatment, and every 2 years after the start of 3,4-DAP treatment. All study participants will then return to the clinic once each year (or more often if the neurologist feels it is necessary) for follow-up care.

Participants will receive treatment with the study drug until it is approved by the FDA for use in patients with CMS, until the investigator stops the study drug (because it doesn't work for the participant or it is unsafe for to take), or until the study is ended for other reasons (i.e. safety concerns are discovered, etc.), whichever comes first. Participants will be allowed to stay on other medications for myasthenia or add other medications to treat their condition, as necessary.

If participants have an unclear history of episodes resembling seizures as determined by the investigator, they should not to drive or operate heavy machinery for the first 6 months of the study.

Participants may not participate in this study if they are pregnant or breastfeeding or if they are a woman of childbearing potential who plans to become pregnant while on the study. It is unclear how 3,4 DAP can effect an unborn fetus. Therefore, women of childbearing potential will have a pregnancy test prior to starting the study drug and periodically throughout the study, if needed. Participants who think they may have become pregnant during the study should tell the study doctor immediately.

Study title	NCT ID	Conditions	Interventions	Eligibility	Organization
Pregnancy Outcomes in Congenital Myasthenie Syndrome	NCT01474980	Congenital Myas...		18 Years -	Institut de Myologie, France
Efficacy of Albuterol in the Treatment of Congenital Myasthenic Syndromes	NCT01203592	Congenital Myas...	Albuterol	2 Years -	Mayo Clinic
Expanded Access Study Amifampridine Phosphate in Lambert-Eaton Myasthenic Syndrome (LEMS),Congenital Myasthenic Syndrome	NCT02189720	Congenital Myas... Lambert-Eaton M... Nystagmus, Acqu...	Amifampridine P...	2 Years -	Catalyst Pharmaceuticals, Inc.
Pregnancy Outcomes in Congenital Myasthenie Syndrome	NCT01474980	Congenital Myas...		18 Years -	Institut de Myologie, France
Expanded Access Study Amifampridine Phosphate in Lambert-Eaton Myasthenic Syndrome (LEMS),Congenital Myasthenic Syndrome	NCT02189720	Congenital Myas... Lambert-Eaton M... Nystagmus, Acqu...	Amifampridine P...	2 Years -	Catalyst Pharmaceuticals, Inc.
A Phase 1b Study to Investigate Safety and Tolerability of ARGX-119 in Adult Participants With DOK7-Congenital Myasthenic Syndromes (CMS)	NCT06436742	Congenital Myas...	ARGX-119 Placebo	18 Years -	argenx
Treatment Use of 3,4 Diaminopyridine in Congenital Myasthenia	NCT03062631	Congenital Myas...	3,4-Diaminopyri...	3 Months - 75 Years	University of California, Davis

Spots Global Cancer Trial Database for congenital myasthenic syndrome