To describe baseline characteristics of participants in the ongoing M-STAR phase 3 study evaluating the disease modifying effect of verdiperstat on multiple system atrophy (MSA).

MSA is a rare, adult-onset, rapidly progressive, and fatal neurodegenerative disease with no disease modifying treatment available. Verdiperstat is a first-in-class, potent, selective, brain-permeable, irreversible myeloperoxidase (MPO) inhibitor. In phase 2 studies in Parkinson’s disease (PD) and MSA, treatment with verdiperstat was generally safe and well tolerated. Verdiperstat decreased MPO activity in plasma, providing evidence of target engagement; reduced translocator protein binding on brain PET imaging in PD, providing proof of mechanism (decreased microglial activation/neuroinflammation); and demonstrated favorable trends on clinical efficacy measures (Unified MSA Rating Scale [UMSARS]) at 12 weeks.

M-STAR is a randomized, double-blind, placebo-controlled, parallel group study. Ambulatory participants, 40-80 years of age, with possible or probable MSA, including MSA-Parkinsonism (MSA-P) or MSA-Cerebellar (MSA-C), are randomized to 48 weeks of treatment with verdiperstat 600 mg twice daily or placebo. The planned sample size is 325 participants. The primary efficacy endpoint is change from baseline to Week 48 in verdiperstat- vs. placebo-treated subjects on a score derived from the UMSARS (based on health authority feedback) optimized to assess clinically meaningful change in ability to function. ClinicalTrials.gov Identifier: NCT03952806. EudraCT Number: 2019-001100-38.

Select baseline characteristics (e.g., age, gender, race, ethnicity, weight) of the enrollees will be presented. Relevant baseline disease characteristics (e.g., disease category [MSA-P vs. MSA-C]; diagnostic certainty [possible vs. probable], UMSARS Part I, Part II, and total score; Clinical and Patient Global Impression of Severity [CGI-S/PGI-S]) scales will be presented.