Objective: To evaluate the effect of prasinezumab on delaying disease progression in participants with early-stage Parkinson’s disease (PD) on stable symptomatic medication.

Background: Prasinezumab is a humanised IgG1 monoclonal antibody that selectively binds aggregated α-synuclein.1,2

Method: PADOVA (NCT04777331) evaluated the efficacy and safety/tolerability of prasinezumab in participants with early-stage PD on stable monoamine oxidase type B inhibitor (MAO-Bi) or L-DOPA monotherapy. Primary endpoint was time to confirmed motor progression (≥5-points increase from baseline on the Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale [MDS-UPDRS] Part III in OFF-medication state). Exploratory subgroup analyses based on baseline demographic and clinical characteristics were performed. Secondary and exploratory efficacy assessments included continuous and time-to-event measures of disease progression, and participant- and clinician-rated global measures of change. The long-term effects of prasinezumab were evaluated through 2.5 years of follow-up, including six months of open-label extension (OLE).

Results: Of 586 participants, 74.2% received L-DOPA and 25.8% MAO-Bi. The primary endpoint did not reach statistical significance p=0.0657). However, a trend for clinical efficacy was observed (Hazard ratio [HR]; 95% confidence interval [CI] =0.84 [0.69–1.01]), more pronounced in the L-DOPA subgroup (HR=0.79 [0.63–0.99]). Pre-specified covariate-adjusted analyses showed nominally significant effects in the overall population (HR=0.81 [0.67–0.98]) and in the L-DOPA subgroup (HR=0.76 [0.61–0.95]). Consistent trends favouring prasinezumab were observed across subgroups and secondary time-to-event endpoints. Six-month OLE data showed persistent reduction of motor progression. Prasinezumab was well tolerated with no new safety signals observed.

Conclusion: Although the primary endpoint was not met, the totality of evidence from PADOVA suggests prasinezumab may slow early-stage PD progression alongside standard therapy. Benefits observed during double-blind treatment persisted through six months of open-label follow-up. These clinical and biological signals support continued investigation in the Phase III PARAISO trial. 

This abstract was previously presented at ADPD 2026 on 21 March 2026.

References: 1. Angot E, et al. Lancet Neurol. 2010; 9(11):1128–38

2. Vekrellis K & Stefanis L. Expert Opin Ther Targets. 2012;16(4):421–32

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MDS Abstracts - https://www.mdsabstracts.org/abstract/prasinezumab-in-early-stage-parkinsons-disease-additional-data-from-the-padova-study/