Supplemental Material for: Measuring Parkinson’s disease progression with wearable sensors: results from a phase 2 clinical trial of cinpanemab

This report evaluates the sensitivity to longitudinal change of QMA-PD, a pre-specified digital composite score derived from wearable sensors, in 357 people with PD participating in the SPARK phase 2 trial of cinpanemab.</p><p dir="ltr"><b>Methods:</b> The QMA-PD composite score is derived from 36 digital measures collected during 5 in-clinic motor tasks.

Measurement properties of the QMA-PD were analyzed, including sensitivity to longitudinal changes based on mixed models for repeated measures.</p><p dir="ltr"><b>Results:</b> The QMA-PD showed longitudinal changes in PD-related motor signs, indicating disease progression, but did not show superior sensitivity to longitudinal changes compared to the rater-based MDS-UPDRS Part 3. In line with clinical and biomarker results, the QMA-PD did not show differences between the cinpanemab and placebo groups at 52 weeks.</p><p dir="ltr"><b>Conclusions:</b> These findings suggest that the substantial inter‑patient variability in disease progression may dominate effects of increased measurement precision, limiting the ability to assess the utility of digital measures in population-level analyses.