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The Efficacy of High-Dose Intravenous Immunoglobulin Therapy in Patients With Stiff-Man Syndrome: A Double-Blind, Placebo-Controlled Trial

Phase 1
Not Enrolling
Muscle Rigidity, Spasm, Stiff Man Syndrome

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Trial Information

The Efficacy of High-Dose Intravenous Immunoglobulin Therapy in Patients With Stiff-Man Syndrome: A Double-Blind, Placebo-Controlled Trial

Stiff-man Syndrome (SMS) is a chronic, disabling neurological disorder characterized by
severe and painful axial and limb rigidity enhanced by anxiety, sudden motion or external
stimuli. Although the cause of SMS is unknown, immunologic mechanisms have been implicated
on the basis of circulating autoantibodies in the patient's serum and CSF, against GAD
(glutamic acid decarboxylase), the enzyme involved in the synthesis of GABA (gamma
aminobutyric acid). Uncontrolled studies have also shown that plasmapheresis,
corticosteroids and high dose intravenous immunoglobulin (IVIg) are variably effective in
improving the clinical symptoms of these patients. The purpose of the present study is to
demonstrate in a double blind, placebo-control design, the efficacy of IVIg in patients with
SMS. The effect of IVIg will be assessed with a series of objective measurements including
muscle function, mobility and stiffness. Changes in the circulating anti-GAD antibodies
will be also examined and their pathogenetic role in the cause of SMS will be determined.
If IVIg proves effective, it will be a valuable tool in the treatment of these patients who
are currently dependent on high doses of Valium (up to 60-100 mg daily), or steroids and
experience significant side effects.

Inclusion Criteria

Men and non-pregnant women, between 18-75 years of age, who meet a defined criteria for
the diagnosis of Stiff-man syndrome (SMS) will be screened as inpatients or in the
outpatient clinic.

If the diagnosis is confirmed, the patients will be enrolled into the protocol, provided
their disease remains symptomatic and poorly responsive to benzodiazepines.

Only patients with anti-GAD antibodies will be included.

Patients who have not received IVIg in the past 6 months may be included.

No pregnant or nursing women (confirmed by a pregnancy screening test).

No critically ill patients, such as those with severe cardiomyopathy, and respiratory
insufficiency and severely incapacitated patients that require help for self care.

No patients with severe renal or hepatic disease, COPD or severe coronary artery disease.

No patients with serum IgA level less than 11 mg/dl.

Type of Study:


Study Design:

Endpoint Classification: Safety Study, Primary Purpose: Treatment


United States: Federal Government

Study ID:




Start Date:

April 1996

Completion Date:

May 2002

Related Keywords:

  • Muscle Rigidity
  • Spasm
  • Stiff Man Syndrome
  • Immunotherapy
  • Muscle Stiffness
  • Rigidity
  • Anti-GAD Antibodies
  • Episodic Spasms
  • Intravenous High-Dose Immunoglobulin
  • Stiff-man Syndrome
  • Muscle Rigidity
  • Multiple Endocrine Neoplasia
  • Spasm
  • Stiff-Person Syndrome



National Institute of Neurological Disorders and Stroke (NINDS) Bethesda, Maryland  20892