Recruitment and Retention in Clinical Trials of Deep Brain Stimulation in Early-Stage Parkinson's Disease: Past Experiences and Future Considerations

Neuropsychological and social predictors of participation in a deep brain stimulation study of Parkinson's disease and dystonia

Objectives

Participation is essential to DBS research, yet circumstances that affect diverse participation remain unclear. Here we evaluate factors impacting participation in an adaptive DBS study of Parkinson's disease (PD) and dystonia.

Methods

Twenty participants were implanted with a sensing-enabled DBS device (Medtronic Summit RC+S) that allows neural data streaming in naturalistic settings and encouraged to stream as much as possible for the first five months after surgery. Using standardized baseline data obtained through neuropsychological evaluation, we compared neuropsychological and social variables to streaming hours.

Results

Marital status and irritability significantly impacted streaming hours (estimate=136.7, bootstrapped ( b ) CI b =45.0 to 249.0, p b =0.016, and estimate=-95.1, CI b =-159.9 to -49.2, p b =0.027, respectively). These variables remained significant after multivariable analysis. Composite scores on verbal memory evaluations predicted the number of hours of data streamed (R 2 =0.284, estimate=67.7, CI b =20.1 to 119.9, p b =0.019).

Discussion

Verbal memory impairment, irritability, and lack of a caregiver may be associated with decreased participation. Further study of factors that impact research participation is critical to the sustained inclusion of diverse participants.

Exit from Brain Device Research: A Modified Grounded Theory Study of Researcher Obligations and Participant Experiences

As clinical trials end, little is understood about how participants exiting from clinical trials approach decisions related to the removal or post-trial use of investigational brain implants, such as deep brain stimulation (DBS) devices. This empirical bioethics study examines how research participants experience the process of exit from research at the end of clinical trials of implanted neural devices. Using a modified grounded theory study design, we conducted semi-structured, in-depth interviews with 16 former research participants from clinical trials of DBS and responsive neurostimulation (RNS). Open-ended questions elicited motivations for joining the trial, understanding of study procedures at the time of initial informed consent, the process of exiting from research, and decisions about device removal or post-trial device use. Thematic analysis identified categories related to: limited preparedness for the end of research participation, straightforwardness of decisions to explant or keep the device, reconciling with the end of research participation, reconciling post-trial expectations, and achieving a sense of closure after exit from research. A preliminary theoretical model describes contextual factors influencing the process and experience of exit from research. Experiences of clinical trial participants should guide research practices to enhance the ethical design and conduct of clinical trials in DBS and other brain devices.

Deep Brain Stimulation in Early-Stage Parkinson's Disease: Patient Experience after 11 Years

The deep brain stimulation (DBS) in early-stage Parkinson's disease (PD) pilot trial began more than a decade ago and remains the only investigation of DBS in mildly symptomatic patients. Patients completed therapeutic washouts biannually for two years, outpatient assessments through five years, and a longitudinal washout assessment after 11 years. Here, the patient experience of participating in the early DBS pilot trial is described. Semi-structured interviews were audio-recorded and transcribed. Transcripts were coded, analyzed using an iterative inductive-deductive approach, and used to develop a conceptual framework. Ten participants (n = 6 early optimal drug therapy (ODT), n = 4 early DBS + ODT) were interviewed. Motivations for participation included benefit to future PD patients and potential personal benefit, while hesitations included risk of surgical complications. While early ODT patients who received standard-of-care DBS described significant changes in their functional capacities after surgery, early DBS patients described a maintenance of quality of life that made PD less impactful over an extended period. Patients expressed high satisfaction with trial participation and early DBS. This study suggests that the PD experience with early DBS may notably differ from standard-of-care DBS. The FDA has approved the conduct of a pivotal clinical trial evaluating DBS in early-stage PD (IDEG050016).

Perceptions about Research Participation among Individuals at Risk and Individuals with Premanifest Huntington's Disease: A Survey Conducted by the European Huntington Association

There has been great progress in Huntington's disease (HD) research. Yet, effective treatments to halt disease before the onset of disabling symptoms are still unavailable. Scientific breakthroughs require an active and lasting commitment from families. However, they are traditionally less involved and heard in studies. Accordingly, the European Huntington Association (EHA) surveyed individuals at risk (HDRisk) and with premanifest HD (PreHD) to determine which factors affect their willingness to participate in research. Questions assessed research experience and knowledge, information sources, reasons for involvement and noninvolvement, and factors preventing and facilitating participation. The survey included 525 individuals, of which 68.8% never participated in studies and 38.6% reported limited research knowledge. Furthermore, 52% trusted patient organizations to get research information. Reasons for involvement were altruistic and more important than reasons for noninvolvement, which were related to negative emotions. Obstacles included time/financial constraints and invasive procedures, while professional support was seen as a facilitator. PreHD individuals reported less obstacles to research participation than HDRisk individuals. Overall, a high motivation to participate in research was noted, despite limited experience and literacy. This motivation is influenced by subjective and objective factors and, importantly, by HD status. Patient organizations have a key role in fostering motivation through education and support.

Overcoming Barriers to Parkinson Disease Trial Participation: Increasing Diversity and Novel Designs for Recruitment and Retention

Parkinson disease (PD) is highly prevalent among neurodegenerative diseases, affecting a diverse patient population. Despite a general willingness of patients to participate in clinical trials, only a subset of patients enroll in them. Understanding the barriers to trial participation will help to alleviate this discrepancy and improve trial participation. Underrepresented minorities, older patients, and patients with more medical comorbidities in particular are underrepresented in research. In clinical trials, this has the effect of delaying trial completion, exacerbating disparities, and limiting our ability to generalize study results. Efforts to improve trial design and recruitment are necessary to ensure study enrollment reflects the diversity of patients with PD. At the trial design level, broadening inclusion criteria, attending to participant burden, and focusing on trial efficiency may help. At the recruitment stage, increasing awareness, with traditional outreach or digital approaches; improving engagement, particularly with community physicians; and developing targeted recruitment efforts can also help improve enrollment of underrepresented patient groups. The use of technology, for virtual visits, technology-based objective measures, and community engagement, can also reduce participant burden and increase recruitment. By designing trials to consider these barriers to trial participation, we can improve not only the access to research for all our patients but also the quality and generalizability of clinical research in PD.

A mixed-methods systematic review of patients' experience of being invited to participate in surgical randomised controlled trials

RATIONALE

Randomised controlled trials (RCTs) of surgical interventions are increasing. Such trials encounter challenges that are not present in RCTs of non-surgical interventions because of the nature of the intervention. Several studies have explored patients' experiences of surgical trials to improve recruitment or identify barriers and facilitators to research in this setting. Synthesizing these studies may reveal further insights or confirm whether saturation of relevant themes has been achieved.

OBJECTIVE

This review aimed to understand the experiences of adults who are invited to participate in surgical RCTs.

METHOD

MEDLINE, Web of Science, and CINAHL were searched to identify articles meeting the inclusion criteria. Assessment of quality was conducted with studies given an overall quality rating of good, fair, or poor. A segregated approach was used to synthesize the data. This method included a thematic synthesis of the qualitative data and a narrative review of the quantitative data. The findings of both syntheses were then integrated.

RESULTS

Thirty-four articles reporting 28 trials were included. This review found that the decision to participate in a surgical trial is influenced by multiple factors including patients' individual circumstances and attitudes, and the characteristics of the trial itself. The study identified three themes which encompass both qualitative and quantitative findings. These themes reveal it was important for patients to i) make sense of the trial and trial processes, ii) weigh up the risks and benefits of their different treatment options and participation, and iii) trust the trial and staff.

CONCLUSIONS

A patient-centred approach to trial recruitment may help staff build trusting relationships with patients and address their individual concerns about the trial and the risks and benefits of participation.

Discovery of VU2957 (Valiglurax): An mGlu4 Positive Allosteric Modulator Evaluated as a Preclinical Candidate for the Treatment of Parkinson's Disease

Herein, we report the discovery of a novel potent, selective, CNS penetrant, and orally bioavailable mGlu₄ PAM, VU0652957 (VU2957, Valiglurax). VU2957 possessed attractive in vitro and in vivo pharmacological and DMPK properties across species. To advance toward the clinic, a spray-dried dispersion (SDD) formulation of VU2957 was developed to support IND-enabling toxicology studies. Based on its overall profile, VU2957 was evaluated as a preclinical development candidate for the treatment of Parkinson's disease.