Disease Progression in Multiple System Atrophy: The ASPIRE Multi-Modal Biomarker Study.

Objective: The objective of this study was to characterize changes in candidate biomarkers in early multiple system atrophy (MSA) and identify baseline predictors of faster progression.

Methods: This 1-year, multicenter, prospective study assessed clinical, neuroimaging (3T-magnetic resonance imaging [MRI], dopamine transporter single-photon emission computed tomography [DaT-SPECT]), and neurofilament light chain (NfL) changes in patients with early MSA (< 5 years from symptom onset) and healthy controls (HCs). Clinical and biomarker changes from baseline to 6 months (M6) and 12 months (M12) were analyzed. Survival status was collected at 24 months. Mixed linear regression analyzed repeated measures, whereas univariate regression identified biomarkers linked to progression. Sample size simulations were conducted for future trials.

Results: Forty-one patients with MSA and 20 HCs were included in this study. The Unified Multiple System Atrophy Rating Scale (UMSARS)-I + II scores worsened (mean percent change from baseline was 19.8% at M6; 95% confidence interval [CI] = 13.3 to 26.4% and 31.1% 95% CI = 24.9 to 37.2% at M12). Patients with MSA showed increased cerebellar white matter and pons atrophy (M6 = -5.9 to -2.8% and M12 = -9 to -4.9%) and decreased striatal specific binding ratio (SBR; M6 = -15.8 to -7.9% and M12 = -24 to -10.4%). Patients with multiple system atrophy parkinsonian (MSA-P) exhibited greater striatal SBR reduction, whereas patients with multiple system atrophy cerebellar (MSA-C) had greater cerebellar and pons atrophy, evident at M6. Baseline brainstem and pons volume predicted clinical worsening at M6, whereas SBR predicted worsening at M12. Higher plasma NfL levels correlated with early dropout (14% at M12), worse UMSARS scores, lower SBR, and increased mortality risk within 24 months.

Interpretation: Neuroimaging changes occur within 6 months in early MSA. High plasma NfL levels are linked to increased mortality and dropout risk. Longitudinal biomarker assessments provide valuable insights into disease progression. ANN NEUROL 2025.