Effect of Verdiperstat on Microglial Activation in Well-characterized MSA Patients

This study will comprise of two phases, an observational phase and a treatment phase. In the observational phase the specific aims are: 1. To determine the presence and regional distribution of microglial activation, as assessed by 18F-PBR06 PET, in subjects with MSA as compared to healthy controls, at baseline and at 6-9 months' follow-up. 2\. To assess the relationship between microglial activation and clinical progression at baseline and follow-up. In the treatment phase the specific aims of the study are: The specific aims of the study are: 1. To assess whether verdiperstat (BHV-3241) reduces 18F-PBR06 PET signal, and thus microglial activation and inflammation, in well-characterized MSA patients. 2. To assess the relationship between PET changes and clinical progression at baseline and follow-up in patients treated with verdiperstat. 3. To assess the relationship between PET changes and volumetric brain MRI at baseline and follow-up in patients treated with verdiperstat. Currently there is no known disease modifying therapy for MSA. Recently, the drug verdiperstat (BHV-3241) has appeared in the investigational arena specifically for the indication of Multiple System Atrophy. Verdiperstat (BHV-3241) is currently being used in a phase 3 active drug trial at Massachusetts Hospital. Verdiperstat (BHV-3241) is known to target Myeloperoxidase, an enzyme implicated in neuroinflammation, a major driver in disease pathogenesis. Our previous study (IRB protocol #2016P002373) demonstrated that applying TSPO (translator protein) PET imaging enabled us to track changes in neuroinflammation and thus provide a viable biomarker for disease progression. In this pilot study, the investigators aim to assess the effect of an investigational drug, verdiperstat (BHV-3241) on microglial activation in MSA patients using \[F-18\]PBR06 and to link it with clinical and morphometric MRI brain changes following treatment.