Use of Immunotherapy and Symptomatic Therapy Differs Between Clinical Phenotypes of Stiff Person Syndrome Spectrum Disorders
Alexandra Simpson1, Alexandra Balshi1, Danielle Obando2, Ashley Miles1, Elena Taylor1, Sarah Snoops1, Yujie Wang3, Scott Newsome1
1Johns Hopkins Hospital, 2Johns Hopkins University School of Medicine, 3UW Northwest
Objective:

To characterize which clinical phenotypes of SPSD require more immunotherapy or symptomatic treatment.

Background:
Stiff person syndrome spectrum disorders (SPSD) include several phenotypes with unique presentations: classic SPS, SPS-plus, pure cerebellar ataxia (CA), partial-SPS, and progressive encephalomyelitis with rigidity and myoclonus (PERM). First-line therapy in SPSD is typically symptomatic in nature, although many patients will ultimately be placed on immune-based treatment. Little is known regarding frequency of use of these interventions in various phenotypes.
Design/Methods:

Individuals with SPSD evaluated at the Johns Hopkins SPS Center from 1997-2022 are followed through a longitudinal cohort study. Data collection occurs during clinic visits and includes demographic data, disease characteristics, laboratory studies, exam findings, and treatment. Treatment is classified as immunotherapy or symptomatic (pharmacological and non-pharmacological) therapy. All current and historical treatments for a patient were included in the descriptive analysis.

Results:

Ultimately, 235 people with a diagnosis of SPSD meeting criteria for a clinical phenotype (155 classic SPS, 45 SPS-plus, 16 PERM, 11 CA, 8 partial-SPS) were included. Mean age was 58±14 years, with the majority female(75%) and white(69%). For immunotherapy, 94% of PERM, 82% of SPS-plus, 75% of classic SPS, 73% of CA, and 38% of partial-SPS patients were prescribed immunotherapy, most commonly intravenous immunoglobulin, rituximab, and/or plasmapheresis. All PERM, 98% of SPS-plus, 97% of classic SPS, 88% of partial-SPS, and 45% of CA patients were prescribed at least one symptomatic therapy, most commonly benzodiazepines and/or baclofen.  

Conclusions:

Individuals with PERM, SPS-plus, and classic SPS were prescribed more immunotherapy and symptomatic therapies. While people with CA were more likely to trial immunotherapy, those with a partial-SPS were more likely to trial symptomatic medications. Further studies will evaluate if perceptions on phenotype clinical severity or lack of effective interventions to target particular symptoms may lead to these differences in clinical care.

10.1212/WNL.0000000000203355