Regional cerebral glucose metabolism after pridopidine (ACR16) treatment in patients with Huntington disease.

Objectives: Huntington disease is a hereditary neurodegenerative disorder resulting in loss of motor, cognitive, and behavioral functions and is characterized by a distinctive pattern of cerebral metabolic abnormalities. Pridopidine (ACR16) belongs to a novel class of central nervous system compounds in development for the treatment of Huntington disease. The objective of the study was to investigate the metabolic changes in patients with Huntington disease before and after pridopidine treatment.

Methods: [(18)F]Fluorodeoxyglucose positron emission tomographic imaging was used to measure the regional cerebral metabolic rate of glucose at baseline and after 14 days of open-label pridopidine treatment in 8 patients with Huntington disease. Clinical assessments were performed using the Unified Huntington's Disease Rating Scale.

Results: Statistical parametric mapping analysis showed increased metabolic activity in several brain regions such as the precuneus and the mediodorsal thalamic nucleus after treatment. In addition, after pridopidine treatment, the correlation between the clinical status and the cerebral metabolic activity was strengthened.

Conclusions: Our findings suggest that pridopidine induces metabolic changes in brain regions implicated as important for mediating compensatory mechanisms in Huntington disease. In addition, the finding of a strong relationship between clinical severity and metabolic activity after treatment also suggests that pridopidine treatment targets a Huntington disease-related metabolic activity pattern.