Many Parkinson’s clinical trials fail to reach Phase 3

The number of active clinical trials for Parkinson’s disease has stayed about the same since 2019. However, many potential treatments, especially those aimed at slowing or stopping the disease, are not progressing from Phase 2 to Phase 3 trials, according to a report. A wide range of treatments are being studied, with more focus recently on those targeting inflammation and non-motor symptoms of the disease. The report, now in its fifth year, is a collaboration among Cure Parkinson’s, The Michael J. Fox Foundation, and other research advocates, providing an overview of current Parkinson’s clinical trials. Simon Stott, PhD, from Cure Parkinson’s, noted the stability of trial numbers during the COVID-19 pandemic as a remarkable achievement and credited the dedication of participants and researchers. The report, "Parkinson’s Disease Drug Therapies in the Clinical Trial Pipeline: 2024 Update," was published in the Journal of Parkinson’s Disease. The number of Parkinson’s trials remained stable in 2023, with 136 trials compared to 139 the previous year. Trials are categorized as either disease-modifying therapies (DMTs) aiming to change the disease’s course or symptomatic treatments that ease symptoms without affecting disease progression. The proportion of DMT trials has slightly increased over the past five years. There was a notable rise in trials focusing on inflammation from 2022 to 2023. While dyskinesia (involuntary muscle movements) was the most targeted symptom, there was also an increase in trials for non-motor symptoms like cognition, depression, and psychosis. Most active trials in 2023 were in Phase 2 (58%), with fewer in Phase 1 (30%) and Phase 3 (12%). Only three Phase 3 trials for DMTs were active in 2023, down from six in 2022, possibly due to a limited understanding of Parkinson’s biology. Cure Parkinson’s is working to improve these numbers with projects like the ACT-PD, which aims to speed up DMT trials in the UK by testing multiple treatments simultaneously and providing more opportunities for patient involvement.