Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2024 Update.

Background: For the past five years, our annual reports have been tracking the clinical development of new drug-based therapies for the neurodegenerative condition of Parkinson's disease (PD). These reviews have followed the progress both of "symptomatic treatments" (ST - improves/reduces symptoms of the condition) and "disease-modifying treatments" (DMT - attempts to delay/slow progression by addressing the underlying biology of PD). Efforts have also been made to further categorize these experimental treatments based on their mechanisms of action and class of drug. Methods: A dataset of clinical trials for drug therapies in PD using trial data downloaded from the ClinicalTrials.gov online registry was generated. A breakdown analysis of all the studies that were active as of January 31st, 2024, was conducted. This analysis involved categorizing the trials based on both the mechanism of action (MOA) and the drug target. Results: There were 136 active Phase 1-3 trials evaluating drug therapies for PD registered on ClinicalTrials.gov, as of January 31, 2024. Of these trials, 76 (56%) were classified as ST trials and 60 (44%) were designated DMT. More than half (58%) of the trials were in Phase 2 testing stage, followed by Phase 1 (30%) and Phase 3 (12%). 35 of the trials were registered since our last report, with the remaining 101 trials appearing in at least one earlier report. Conclusions: The drug development pipeline for PD remains in a robust state with a wide variety of approaches being developed and evaluated in Phase 1 and 2. Yet again, however, only a limited number of DMTs are transitioning to Phase 3.

The development of new medical therapies, particularly for neurodegenerative conditions, is a long process that involves multiple phases of testing before a treatment is approved for use in a doctor's clinic. The first phase assesses the short-term safety of a drug ­ most often in healthy volunteers but sometimes in people affected by the disease. The second phase explores the short-term safety and preliminary efficacy of the agent in people affected by the disease of interest, and the third phase investigates long-term safety and efficacy in a large group of people affected by the disease. For a disease like Parkinson's disease, where the causes of the condition are not well understood, drugs targeting different biological pathways need to be tested to determine which ones may be useful in treating the symptoms, and which could be administered to slow down or stop the progression of the condition. Here, we provide an annual report on the current landscape of both these clinical testing efforts. In total, we reviewed 136 active studies evaluating therapies for Parkinson's disease registered on a clinical trial database called 'ClinicalTrials.gov'. Of these trials, approximately 55% were testing experimental symptomatic treatments, while the rest were focused on slowing down disease progression. More than half (58%) of the studies were in the second phase of clinical testing (short-term safety and preliminary efficacy), but only three studies were found to be testing treatments to stop the progression of Parkinson's in the Phase 3 testing. We concluded that the drug development pipeline for Parkinson's is robust, but more progress needs to be made with late-stage testing of treatments to slow the disease.

Patient and Public Involvement and Engagement in the Development of a Platform Clinical Trial for Parkinson's Disease: An Evaluation Protocol.

Background: Patient and public involvement and engagement (PPIE) in the design of trials is important, as participant experience critically impacts delivery. The Edmond J Safra Accelerating Clinical Trials in PD (EJS ACT-PD) initiative is a UK consortium designing a platform trial for disease modifying therapies in PD. Objective: The integration of PPIE in all aspects of trial design and its evaluation throughout the project. Methods: PwP and care partners were recruited to a PPIE working group (WG) via UK Parkinson's charities, investigator patient groups and participants of a Delphi study on trial design. They are supported by charity representatives, trial delivery experts, researchers and core project team members. PPIE is fully embedded within the consortium's five other WGs and steering group. The group's terms of reference, processes for effective working and PPIE evaluation were co-developed with PPIE contributors. Results: 11 PwP and 4 care partners have supported the PPIE WG and contributed to the development of processes for effective working. A mixed methods research-in-action study is ongoing to evaluate PPIE within the consortium. This includes the Patient Engagement in Research Scale -a quantitative PPIE quality measure; semi-structured interviews -identifying areas for improvement and overall impressions of involvement; process fidelity- recording adherence; project documentation review - identifying impact of PPIE on project outputs. Conclusions: We provide a practical example of PPIE in complex projects. Evaluating feasibility, experiences and impact of PPIE involvement in EJS ACT-PD will inform similar programs on effective strategies. This will help enable future patient-centered research.

An International Multi-Stakeholder Delphi Survey Study on the Design of Disease Modifying Parkinson's Disease Trials.

BACKGROUND: Design of disease modification (DM) trials for Parkinson's disease (PD) is challenging. Successful delivery requires a shared understanding of priorities and practicalities. OBJECTIVE: To seek stakeholder consensus on phase 3 trials' overall goals and structure, inclusion criteria, outcome measures, and trial delivery and understand where perspectives differ. METHODS: An international expert panel comprising people with Parkinson's (PwP), care partners (CP), clinical scientists, representatives from industry, funders and regulators participated in a survey-based Delphi study. Survey items were informed by a scoping review of DM trials and PwP input. Respondents scored item agreement over 3 rounds. Scores and reasoning were summarized by participant group each round until consensus, defined as≥70% of at least 3 participant groups falling within the same 3-point region of a 9-point Likert scale. RESULTS: 92/121 individuals from 13 countries (46/69 PwP, 13/18 CP, 20/20 clinical scientists, representatives from 8/8 companies, 4/5 funders, and 1/1 regulator) completed the study. Consensus was reached on 14/31 survey items: 5/8 overall goals and structure, 1/8 Eligibility criteria, 7/13 outcome measures, and 1/2 trial delivery items. Extent of stakeholder endorsement for 428 reasons for scores was collated across items. CONCLUSIONS: This is the first systematic multi-stakeholder consultation generating a unique repository of perspectives on pivotal aspects of DM trial design including those of PwP and CP. The panel endorsed outcomes that holistically measure PD and the importance of inclusive trials with hybrid delivery models. Areas of disagreement will inform mitigating strategies of researchers to ensure successful delivery of future trials.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2023 Update.

BACKGROUND: Since 2020, annual reports on the clinical development of new drug-based therapies for the neurodegenerative condition of Parkinson's disease (PD) have been generated. These reviews have followed the progress of both "symptomatic treatments" (ST - improves/reduces symptoms of the condition) and "disease modifying treatments" (DMT - attempts to delay/slow progression by addressing the underlying biology of PD). Additional efforts have been made to further categorize these experimental treatments based on their mechanisms of action and class of drug. METHODS: A dataset of clinical trials for drug therapies in PD was obtained using trial data downloaded from the ClinicalTrials.gov online registry. A breakdown analysis of all the studies that were active as of January 31st, 2023, was conducted. RESULTS: There was a total of 139 clinical trials registered on the ClinicalTrials.gov website as active (with 35 trials newly registered since our last report). Of these trials, 76 (55%) were considered ST and 63 (45%) were designated DMT. Similar to previous years, approximately a third of the studies were in Phase 1 (n = 47; 34%), half (n = 72, 52%) were in Phase 2 and there were 20 (14%) studies in Phase 3. Novel therapies again represented the most dominant group of experimental treatments in this year's report with 58 (42%) trials testing new agents. Repurposed drugs are present in a third (n = 49, 35%) of trials, with reformulations and new claims representing 19% and 4% of studies, respectively. CONCLUSIONS: Our fourth annual review of active clinical trials evaluating ST and DMT therapeutics for PD demonstrates that the drug development pipeline is dynamic and evolving. The slow progress and lack of agents transitioning from Phase 2 to Phase 3 is concerning, but collective efforts by various stakeholders are being made to accelerate the clinical trial process, with the aim of bringing new therapies to the PD community sooner.

Alpha-synuclein and the Parkinson's disease drug pipeline.

The process of protein aggregation involves the transformation of soluble peptides into insoluble cross-beta amyloids. In Parkinson's disease (PD), soluble monomeric α-synuclein transforms into the amyloid state known as Lewy pathology. Monomeric (functional) α-synuclein depletes as the fraction of Lewy pathology increases. We examined the allocation of disease-modifying projects in the PD therapeutic pipeline classified based on whether they aimed to reduce directly or indirectly the insoluble or increase the soluble α-synuclein. A project was defined as a drug development program that may include more than one registered clinical trial, according to the Parkinson's Hope List, a database of therapies under development for PD. Of 67 projects, 46 aimed to reduce α-synuclein, 15 (22.4%) directly and 31 (46.3%) indirectly, amounting to 68.7% of all disease-modifying projects. No projects explicitly aimed to increase soluble α-synuclein levels. Altogether, α-synuclein is the target of more than two-thirds of the disease-modifying pipeline, with treatments aimed at reducing or preventing an increase in its insoluble fraction. As no treatments aim to restore soluble α-synuclein levels within a normal range, we propose rebalancing the therapeutic PD pipeline.

Towards a multi-arm multi-stage platform trial of disease modifying approaches in Parkinson's disease.

An increase in the efficiency of clinical trial conduct has been successfully demonstrated in the oncology field, by the use of multi-arm, multi-stage trials allowing the evaluation of multiple therapeutic candidates simultaneously, and seamless recruitment to phase 3 for those candidates passing an interim signal of efficacy. Replicating this complex innovative trial design in diseases such as Parkinson's disease is appealing, but in addition to the challenges associated with any trial assessing a single potentially disease modifying intervention in Parkinson's disease, a multi-arm platform trial must also specifically consider the heterogeneous nature of the disease, alongside the desire to potentially test multiple treatments with different mechanisms of action. In a multi-arm trial, there is a need to appropriately stratify treatment arms to ensure each are comparable with a shared placebo/standard of care arm; however, in Parkinson's disease there may be a preference to enrich an arm with a subgroup of patients that may be most likely to respond to a specific treatment approach. The solution to this conundrum lies in having clearly defined criteria for inclusion in each treatment arm as well as an analysis plan that takes account of predefined subgroups of interest, alongside evaluating the impact of each treatment on the broader population of Parkinson's disease patients. Beyond this, there must be robust processes of treatment selection, and consensus derived measures to confirm target engagement and interim assessments of efficacy, as well as consideration of the infrastructure needed to support recruitment, and the long-term funding and sustainability of the platform. This has to incorporate the diverse priorities of clinicians, triallists, regulatory authorities and above all the views of people with Parkinson's disease.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2022 Update.

BACKGROUND: As the international community dealt with the ongoing COVID-19 pandemic, important progress continued to be made in the development of new drug-based therapies for the neurodegenerative condition of Parkinson's disease (PD) in 2021. This progress included both "symptomatic treatments" (ST - improves/reduces symptoms of the condition) and "disease modifying treatments" (DMT - attempts to delay/slow progression by addressing the underlying biology of PD), which can be categorised further based on their mechanisms of action and class of drug. OBJECTIVE: This report continues previous efforts to provide an overview of the pharmacological therapies - both ST and DMT - in clinical trials for PD during 2021- 2022, with the aim of creating greater awareness and involvement in the clinical trial process. We also hope to stimulate collaboration amongst all stakeholders, including industry, academia, advocacy organizations, and most importantly patient community. METHODS: We conducted a review of clinical trials of drug therapies for PD using trial data obtained from the ClinicalTrials.gov and World Health Organisation (WHO) registries, and performed a breakdown analysis of studies that were active as of January 31st 2022. We also assessed active drug development projects that had completed one clinical phase but were yet to start the next. RESULTS: There was a total of 147 clinical trials registered on the ClinicalTrials.gov website as active during the period of analysis. Of these trials, 91 (62%)were investigating STs, while 56 (38%)focused on DMTs. Approximately 1/3 of the studies (34.7%; 51 trials) were in Phase 1, while over half of the trials were in Phase 2 (50.3%; 74 trials). Only 15% (22 trials) of the studies were in Phase 3, of which only 3 trials were evaluating DMTs. Novel therapeutics (42%)were the most common type of agents being tested across all phases of testing, followed by repurposed agents (34%)and reformulations (20%). CONCLUSION: Despite significant global health constraints, the development of new drug-based therapies for PD continued in 2021. Hopefully with a shift towards a post-pandemic world in which COVID-19 is better managed, we will see an increase in the number of clinical trials focused on drug development for PD. The need for more Phase 3 studies for DMTs remains acute.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2021 Update.

BACKGROUND: Despite the COVID-19 pandemic, there has been considerable activity in the clinical development of novel and improved drug-based therapies for the neurodegenerative condition of Parkinson's disease (PD) during 2020. The agents that were investigated can be divided into "symptomatic" (alleviating the features of the condition) and "disease modifying" (attempting to address the underlying biology of PD) treatments, ST and DMT respectively, with further categorisation possible based on mechanism of action and class of therapy. OBJECTIVE: Our goal in this report was to provide an overview of the pharmacological therapies -both ST and DMT - in clinical trials for PD during 2020-2021, with the aim of creating greater awareness and involvement in the clinical trial process. We also hope to stimulate collaboration amongst commercial and academic researchers as well as between the research and patient communities. METHODS: We conducted a review of clinical trials of drug therapies for PD using trial data obtained from the ClinicalTrials.gov and World Health Organisation (WHO) registries, and performed a breakdown analysis of studies that were active as of February 18th 2021. We also assessed active drug development projects that had completed one clinical phase but were yet to start the next. RESULTS: We identified 142 trials on ClinicalTrials.gov and 14 studies on the WHO registries that met our analysis criteria. Of these 156 trials, 91 were ST and 65 were DMT, Of the 145 trials registered on ClinicalTrials.gov in our 2020 analysis, 45 fell off the list and 42 were added. Despite this change, the balance of ST to DMT; the distribution across phases; the profile of therapeutic categories; and the proportion of repurposed therapies (33.5%); all remained very similar. There are only two DMTs in phase 3, and we identified 33 in-between-phase projects. CONCLUSIONS: Despite the effects of the coronavirus pandemic, investment and effort in clinical trials for PD appears to remain strong. There has been little change in the profile of the clinical trial landscape even though, over the past year, there has been considerable change to the content of the list.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2020.

BACKGROUND: The majority of current pharmacological treatments for Parkinson's disease (PD) were approved for clinical use in the second half of the last century and they only provide symptomatic relief. Derivatives of these therapies continue to be explored in clinical trials, together with potentially disease modifying therapies that can slow, stop or reverse the condition. OBJECTIVE: To provide an overview of the pharmacological therapies- both symptomatic and disease modifying- currently being clinically evaluated for PD, with the goal of creating greater awareness and opportunities for collaboration amongst commercial and academic researchers as well as between the research and patient communities. METHODS: We conducted a review of clinical trials of drug therapies for PD using trial data obtained from the ClinicalTrials.gov database and performed a breakdown analysis of studies that were active as of January 21, 2020. RESULTS: We identified 145 registered and ongoing clinical trials for therapeutics targeting PD, of which 51 were Phase 1 (35% of the total number of trials), 66 were Phase 2 (46% ), and 28 were Phase 3 (19% ). There were 57 trials (39% ) focused on long-term disease modifying therapies, with the remaining 88 trials (61% ) focused on therapies for symptomatic relief. A total of 50 (34% ) trials were testing repurposed therapies. CONCLUSION: There is a broad pipeline of both symptomatic and disease modifying therapies currently being tested in clinical trials for PD.