DUBLIN, March 23 — Prothena Corporation plc (NASDAQ:PRTA), a late-stage clinical biotechnology company with a robust pipeline of investigational therapeutics built on protein dysregulation expertise, today announced partner presentations on clinical updates from prasinezumab for the treatment of Parkinson’s disease and BMS-986446 for the treatment of Alzheimer’s disease at the International Conference on Alzheimer’s and Parkinson’s Diseases and Related Neurological Disorders (AD/PD™ 2026) in Copenhagen, Denmark, and online.
Roche Presentations on Prasinezumab for the Potential Treatment of Parkinson’s Disease
Industry Symposium – Pathways to Progress: Exploring Innovations in AD and PD for Future Practice
- Chair: Malú G. Tansey, Ph.D., Indiana University School of Medicine Stark Neuroscience Institute
- Date: Tuesday March 17, 2026
This symposium reviewed the evolving understanding of the molecular pathophysiology and disease heterogeneity across Alzheimer’s disease (AD) and Parkinson’s disease (PD). Explored current and emerging treatment pathways, e.g. alpha-synuclein, amyloid-beta and neuroinflammation; including diagnostics, biomarkers and therapeutics. Considered how the advancing understanding of AD and PD informs innovative clinical development approaches and clinical practice.
Oral Presentation – Modeling Parkinson’s Disease Progression to Quantify Long-Term Treatment Effects via the Concept of ‘Time Saved’
- Presenter: Benjamin Ribba, Roche
- Date: Thursday March 19, 2026
The comparison of PASADENA open-label extension (OLE) data with PPMI-based model predictions supports potential disease-modifying efficacy with an estimated two years of ‘time saved’ providing an intuitive measure of long-term benefit. The observed PASADENA OLE outcomes consistently deviated from the model-predicted progression, suggesting a sustained treatment effect. On average, participants were approximately two years less advanced in disease severity five years after the start of the trial compared to the virtual comparator.
Oral Presentation – Prasinezumab in Early-Stage Parkinson’s Disease: Additional Data from the PADOVA Study
- Presenter: Tania Nikolcheva, M.D., Ph.D., Roche
- Date: Saturday March 21, 2026
Longer term data from the PADOVA OLE study in early-stage PD showed a sustained effect of prasinezumab in slowing Parkinson’s progression on top of effective symptomatic therapies. The totality of the evidence suggests a possible clinical benefit of prasinezumab and informed the initiation of the Phase III PARAISO study.
Poster Presentation – Prasinezumab’s Impact on Neuromelanin- and Iron-Sensitive MRI Biomarkers in Parkinson’s Disease: Findings from the PADOVA Phase IIb Study
Exploratory biomarker analysis of PADOVA suggests that prasinezumab is biologically active. This is supported by imaging biomarkers crucial to PD pathology, showing a slowing in the progressive loss of neuromelanin signal in substania nigra pars compacta and reduced iron accumulation in the putamen.
Poster Presentation – Sustained Effect on Prasinezumab on Parkinson’s Disease Motor Progression in the Open-Label Extension of the PASADENA Trial, 5-Year Update
At Year 5, the combined PASADENA arm (delayed- and early-start groups) showed less disease progression compared to the PPMI cohort. This lower progression was observed across multiple measures.
Poster Presentation – Digital Health Technology Detects Group Differences in Practically-Defined OFF L-DOPA State: Results of PADOVA Phase IIb Study of Prasinezumab
Post-hoc Digital Health Technology analyses showed consistent trends favoring prasinezumab in digital data collected in the practically-defined OFF L-DOPA state, in line with the PASADENA Phase 2a Simple Sum digital finding and clinical PADOVA readout.
Bristol Myers Squibb Presentation on BMS-986446 for the Potential Treatment of Alzheimer’s Disease
Oral Presentation – Randomized, Double-Blind, Placebo-Controlled Study Evaluating Safety, Tolerability, Pharmacokinetics, and Immunogenicity of BMS-986446 in Healthy Participants, Including Those of Japanese Ethnicity
- Presenter: Ilena George, M.D., Bristol Myers Squibb
- Date: Saturday March 21, 2026
Single-dose BMS-986446 was safe and well tolerated in all participants, including those of Japanese ethnicity. Plasma exposure of BMS-986446 increased dose proportionally. No anti-drug antibodies were detected. These results support BMS-986446 dosing in ongoing clinical studies without adjustments for Japanese ethnicity.
