Intravenous Immunoglobulin and Plasma Exchange in Myasthenia Gravis

Recruitment & Eligibility

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

Study & Design

Arm && Interventions

Group	Intervention	Description
IVIG	IVIG	Intravenous Immunoglobulin, 2G/Kg, infused over 2 days in the Medical Day Unit of the University Health Network
PLEX	PLEX	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.

Primary Outcome Measures

Name	Time	Method
Change in Quantitative Myasthenia Gravis Score (QMGS) from baseline to day 14 after treatment	QMGS at day 14, and patients followed to day 60	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.

Secondary Outcome Measures

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

Recruitment & Eligibility