Intravenous Immunoglobulin and Plasma Exchange in Myasthenia Gravis

Study Overview
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Brief Summary
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Immunomodulation is effective in treating patients with myasthenia gravis (MG), but prior studies have not adequately defined if plasma exchange (PLEX) in superior to intravenous immunoglobulin (IVIG) in the treatment of myasthenia gravis. This study aimed to determine if PLEX was superior to IVIG in the treatment of patients with myasthenia gravis. Patients with MG requiring immunomodulation are randomized to IVIG or PLEX and treated with a full course of immunomodulation. The quantitative myasthenia gravis score (QMGS) will be evaluated as the primary efficacy parameter at day 14 to determine if PLEX is superior to IVIG.

Official Title
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A Randomized Trial of Plasma Exchange vs. IVIG in the Treatment of Myasthenia Gravis

Conditions
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Myasthenia Gravid

Intervention / Treatment
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* Biological: IVIG
* Procedure: PLEX


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: >18 years old diagnosis of moderate-severe MG (defined as a Quantitative Myasthenia Gravis Score QMGS >10.5) worsening weakness requiring a change in therapy judged by a neuromuscular expert Exclusion Criteria: Worsening weakness secondary to concurrent medications (e.g. Aminoglycosides) Worsening weakness secondary to infection Change in corticosteroid dosage in the 2 weeks prior to screening Other disorders causing weakness or fatigue Known absolute IgA deficiency (risk of anaphylactic reaction to IVIG) History of anaphylaxis or severe systemic response to IVIG or albumin Pregnancy or breastfeeding Active renal failure precluding volume of IVIG (risk of volume overload with IVIG) as judged by the investigators Clinically significant cardiac disease precluding IVIG volume as judged by the investigators Known hyperviscosity or hypercoaguable state (risk of stroke with IVIG) Known coagulopathy with bleeding On another current study medication or protocol within 4 weeks of screening Patients with known refractory status to either IVIG or PLEX Poorly controlled or severe hypertension (exacerbation by IVIG) Patient refuses treatment with either IVIG or PLEX Patient refuses follow-up with electrophysiological studies Patient unable or unwilling to give informed consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: IVIG<br>Intravenous Immunoglobulin, 2G/Kg, infused over 2 days in the Medical Day Unit of the University Health Network | Biological: IVIG<br>* Intravenous immunoglobulin<br>|
| Experimental: PLEX<br>Patients received one plasma volume plasma exchanges with 5% albumin replacement fluid. Five plasma exchange procedures occurred every second day with breaks over the weekend allowed. Patients treated in the apheresis units at the University Health Network. | Procedure: PLEX<br>* Plasma exchange: removal of pathogenic antibodies and constituents and replacement with albumin.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Quantitative Myasthenia Gravis Score (QMGS) from baseline to day 14 after treatment | QMGS is a validated clinical measure of myasthenia gravis ranging from 0 points (no myasthenic weakness) to a maximum of 39 points, with a defined change of 3.4 units required for clinical significance. | QMGS at day 14, and patients followed to day 60 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| QMGS Score change at days 21 and 28 from start of treatment. | Change in QMGS with time to see if effect ad day 14 is sustained. | 28 days | 
| Post intervention status | Categorical scale of improvement, worsening, or no change for myasthenia gravis. | Day 14, 21 and 28 | 
| Single fiber electromyography: jitter, percent abnormal pair, percent blocking | Electrophysiological assessment of neuromuscular transmission. | Days 14 and 28 compared to baseline | 
| Repetitive Nerve stimulation studies | Assessment of decrement | Days 14 and 28 | 
| Acetylcholine Receptor Antibody titers | Laboratory assay of pathogenic antibody | Day 28 (if positive at baseline) | 
| AntiMUSK antibody | Laboratory measure of pathogenic antibody | Day 28 (if positive at baseline) | 
| Need for ICU admission, ventilation, intubation | Myasthenic deterioration and crisis | 60 days | 
| Hospitalization | Myasthenic deterioration and crisis | 60 days | 
| Need for additional myasthenic treatment | Myasthenic deterioration or crisis | Day 60 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Myasthenia Gravis, IVIG, PLEX