Genentech's Phase IIb Study of Prasinezumab in Early-Stage Parkinson's Disease Misses Primary Goal

Genentech, part of the Roche Group, has announced that its Phase IIb study of Prasinezumab in early-stage Parkinson's disease did not achieve its primary endpoint. However, the study suggested possible benefits, including a numerical delay in motor progression and positive trends across multiple secondary and exploratory endpoints.

The Phase IIb PADOVA study involved 586 individuals with early-stage Parkinson's disease, who were treated for at least 18 months while on stable symptomatic treatment. Prasinezumab demonstrated potential clinical efficacy in the primary endpoint of time to confirmed motor progression, with a hazard ratio (HR) of 0.84 [0.69-1.01] and a p-value of 0.0657, which did not reach statistical significance.

A pre-specified analysis revealed a more pronounced effect of Prasinezumab in the population treated with levodopa, which constituted 75% of the participants, showing a HR of 0.79 [0.63-0.99]. The study also observed consistent positive trends across several secondary and exploratory endpoints. Prasinezumab was well tolerated, with no new safety signals identified.

Genentech noted that the Phase II PASADENA and Phase IIb PADOVA open-label extension studies will continue to explore the observed effects. Roche/Genentech plans to further evaluate the data and collaborate with health authorities to determine the next steps.