Subcutaneous Immune Globulin May Be a Treatment Option in Stiff Person Syndrome Patients Intolerant to Intravenous Immune Globulin

Stiff person syndrome (SPS) is a rare immune-mediated neurological disorder characterized by rigidity in the trunk and limbs, muscle spasms and heightened sensitivity to outside stimuli, which has been shown to respond to intravenous immune globulin (IVIG). However, IVIG therapy can be associated with a number of challenges, including poor tolerability, a requirement for intravenous access, the need for monthly infusion visits, and serious adverse events that can include aseptic meningitis, renal complications and thrombosis. For certain other chronic neurological conditions, subcutaneous immune globulin (SCIG) has emerged as an alternative to IVIG with comparable efficacy.

The Johns Hopkins Stiff Person Syndrome Center identified five SPS patients, with a mean duration of illness of 5.9 years (range 2.5 to 7 years), who switched to SCIG from IVIG as the result of IVIG- related side effects. All patients were treated with IVIG for at least two months (maximum 18 months) prior to switching to SCIG.

The duration of use of SCIG ranged from four months to six years (mean, 19.2 months). SPS symptoms remained stable in all patients following crossover to SCIG therapy. The treatment was well-tolerated in four of the five patients, one of whom reported mild tolerable injection site reactions. A fifth patient, with a history of asthma and bronchospasm reactions to IVIG treatment, developed escalating side effects, including breathing issues suggestive of a hypersensitivity reaction, which resulted in discontinuation of SCIG treatment after four months.

The study authors concluded that SCIG may be a reasonable and safe alternative for SPS patients who do not tolerate IVIG, with the caveat that allergic and injection site reactions can be a limiting factor for some patients. They called for controlled studies to confirm SCIG treatment durability and efficacy in this patient population.