Background: Neurodegenerative ataxias, including spinocerebellar ataxias (SCAs), are progressive diseases without effective treatment. There is preclinical evidence that inflammation may contribute to neuronal injury in several neurodegenerative ataxias. Intravenous immune globulin (IVIG) is a therapeutic modality that is used as treatment of several autoimmune and inflammatory disorders.

Methods: The primary objective of this open-label pilot study was to assess the effect of IVIG on neurodegenerative ataxias as measured by total scale for the assessment and rating of ataxia (SARA) score. Three patients received IVIG (2 g/kg of body weight, divided over 5 days) once monthly for 3 months, and were evaluated before the first infusion, 2 weeks after each infusion, as well as 28 and 56 days following the final course of treatment. Secondary measures included SARA subsection scores and gait assessment using the GAITRite® Walkway System. Another SCA 3 patient at a different site was treated with six monthly courses of IVIG, and assessed with the SARA score.

Results: Three out of five patients completed the open-label study (SCA 3, a neurodegenerative ataxia associated with an aprataxin genetic variant, and late onset cerebellar ataxia (LOCA) patient). All three patients demonstrated improvement in the SARA score following IVIG. SARA total scores improved by 30-50% and gait sub-scores improved by 20-50% after the last course of IVIG. Clinical improvements attenuated approximately 2 months following the last infusion. The SCA 3 patient treated at another site with a longer protocol had even greater improvement in the SARA score.

Conclusions: IVIG may have therapeutic efficacy in neurodegenerative ataxias, including SCA and LOCA.