Trial results for prasinezumab in participants with early Parkinson's Disease were posted on 2025-12-02. The study showed that participants treated with prasinezumab had a median time to confirmed motor progression event of 61.1 weeks, compared to 49.7 weeks for those receiving placebo. This suggests a delay in disease progression.
Background
Prasinezumab is an investigational drug evaluated for the treatment of Early Parkinson's Disease. The study aimed to assess its efficacy and safety in participants who were already on stable symptomatic Parkinson's Disease medication.
Trial design
The study (NCT04777331) was a multicenter, randomized, double-blind, placebo-controlled Phase 2 trial. It enrolled 586 participants with Early Parkinson's Disease who were on stable symptomatic medication. Participants received either intravenous prasinezumab or placebo to evaluate efficacy and safety.
Key results
Results from the trial indicated several differences between the prasinezumab and placebo groups across various measures of disease progression:
- For "Time to Confirmed Motor Progression Event Assessed by Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III," the median time was 61.1 weeks for the prasinezumab group, compared to 49.7 weeks for the placebo group. The hazard ratio was 0.84 (95.0% CI: 0.69 to 1.01) with a p-value of 0.0657.
- Regarding "Time-to-worsening of Participant's Motor Function as Reported by the Participant in the Presence of a Confirmed Motor Progression Event," the median time was 112.1 weeks for prasinezumab versus 88.3 weeks for placebo. The hazard ratio was 0.82 (95.0% CI: 0.66 to 1.03) with a p-value of 0.0914.
- For "Time to Meaningful Worsening in Participant Global Impression of Change (PGI-C) Overall Disease Subscale," the median time was 44.4 weeks for prasinezumab compared to 36.1 weeks for placebo. The hazard ratio was 0.88 (95.0% CI: 0.73 to 1.05) with a p-value of 0.1574.
- In "Time to Meaningful Worsening in Clinician Global Impression of Change (CGI-C) Overall Disease Subscale," the median time was 60.6 weeks for prasinezumab versus 52.1 weeks for placebo. The hazard ratio was 0.83 (95.0% CI: 0.69 to 1.01) with a p-value of 0.0622.
- For "Time to Onset of Motor Complications as Assessed Through MDS-UPDRS Part IV," the median time was 100.1 weeks for prasinezumab compared to 91.1 weeks for placebo. The hazard ratio was 0.94 (95.0% CI: 0.75 to 1.17) with a p-value of 0.5515.
- For "Change in Motor Function From Baseline to Week 76, as Measured by the MDS-UPDRS Part III Score," the mean change was 3.61 Units on a scale (Standard Error: 0.597) for prasinezumab, compared to 4.00 Units on a scale (Standard Error: 0.592) for placebo. The difference in adjusted means was -0.39 (95.0% CI: -1.84 to 1.05) with a p-value of 0.5944.
What this means
The trial results for prasinezumab in early Parkinson's Disease indicate a consistent trend towards delaying motor progression and other measures of disease worsening compared to placebo. While several hazard ratios were below 1.0, suggesting a benefit, the p-values for these outcomes did not reach conventional statistical significance (e.g., 0.0657 for time to confirmed motor progression). However, the observed longer median times to various progression events and a smaller mean change in MDS-UPDRS Part III score for the prasinezumab group suggest a potential clinical benefit that warrants further investigation. These findings provide important data for understanding the drug's activity in this patient population.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04777331, titled "A Study to Evaluate the Efficacy and Safety of Intravenous Prasinezumab in Participants With Early Parkinson's Disease," were posted on 2025-12-02 on clinicaltrials.gov.