Roche Advances Prasinezumab Into Phase III Trials for Parkinson’s Despite Mixed Phase II Results
Roche is moving prasinezumab, an investigational anti-alpha-synuclein antibody, into Phase III trials for early-stage Parkinson’s disease despite mixed outcomes in previous studies12345.
Prasinezumab targets aggregated alpha-synuclein, a protein implicated in Parkinson's progression, and aims to slow disease decline by modifying underlying biology35.
Phase IIb PADOVA study and its open-label extensions (OLEs) showed the primary endpoint (time to confirmed motor progression) did not reach statistical significance35.
Despite missing the primary endpoint, Roche highlighted positive trends in reducing motor progression at 104 weeks and favorable safety/tolerability, alongside biomarker evidence of biological impact35.
Approximately 10 million people globally are affected by Parkinson’s disease, representing a significant unmet need and large potential market opportunity5.
Roche’s decision is based on the totality of Phase II data, including efficacy signals and promising long-term safety and effectiveness, making prasinezumab a potential first disease-modifying therapy for early-stage patients35.
Sources:
1. https://www.businesswire.com/news/home/20250615297680/en/Prothenas-Partner-Roche-to-Advance-Prasinezumab-into-Phase-III-Development-for-Early-Stage-Parkinsons-Disease
2. https://www.biopharmadive.com/news/roche-prothena-parkinsons-drug-prasinezumab-phase3/750791/
3. https://www.biotechreality.com/2025/06/roche-advances-prasinezumab-into-phase-iii-for-early-parkinsons-disease-citing-promising-data.html
4. https://pharmafile.com/news/roche-advances-treatment-for-parkinsons-disease/
5. https://www.stocktitan.net/news/RHHBY/roche-to-advance-prasinezumab-into-phase-iii-development-for-early-3hqet89rllbn.html