Randomized Placebo Controlled Trial of IVIg in Glycine Receptor Antibody Positive Stiff-person Syndrome

The purpose of this study is to determine whether intravenous immunoglobulin (IVIG) treatment
reduces stiffness and spasms in patients with SPS spectrum disorders compared to patients who
do not receive any treatment. In this study, investigators want to compare the effects, good
and/or bad, of IVIG with placebo on participants with SPS to find out which is better. This
is a "randomized, double-blind" study. Which treatment participants will receive is randomly
determined. Participants have an equal chance of receiving IVIG or the placebo.

SPS spectrum cohort will include any from the SPS spectrum patient (stiff-limbs, stiff-trunk,
stiff-limbs and trunk, and PERM). Study visits will be considered part of clinical care and
will occur at: enrollment (will coincide with screening visit), and 11 weeks. IVIg/placebo
(saline) treatments will be administered on 2 consecutive days in week 1, week 5, week 9 in
all patients.

Inclusion Criteria

- Patient must be 18 years of age or older

- Must have symptoms of SPS for less than 3 years

- If taking corticosteroids, the patients must be on a stabile dose for 30 days prior to
enrolment

- Patients will have a diagnosis of SPS spectrum disorder based on both of clinical and
serological status

Exclusion Criteria

- Patients on immune suppressants initiated/dose increased in the prior 6 months

- History of thrombotic episodes within the 2 years prior to enrollment

- Known allergic or other severe reactions to blood products including intolerability to
previous IVIG

- Previous adequate trial of IVIG as determined by the Principal Investigator

- IgA deficiency

- Reproductive status:

- Women who are pregnant, breastfeeding

- Women and men of childbearing potential who are unwilling or unable to use an
acceptable method of birth control to avoid pregnancy for the entire study
period, as evaluated by the investigator.

- Any surgical procedure within 4 weeks prior to baseline.

- Evidence of serious uncontrolled concomitant diseases that may preclude patient
participation; Other nervous system disease, cardiovascular disease,
hematologic/hematopoiesis disease, respiratory disease, muscular disease, endocrine
disease, renal/urologic disease, digestive system disease, congenital or acquired
severe immunodeficiency

- Known active infection within 4 weeks prior to baseline.

- Evidence of chronic active hepatitis B or C.

- Active ischemic heart disease in the past year prior to baseline.

- Patients should not have severe renal or hepatic disease

- Severe hypertension