The third most common barrier to conducting an effective clinical trial identified 'recruitment of people with Parkinson’s' to specific studies (43%)


Clinical trials are necessary to see how effective or safe certain treatments, interventions or diagnostic tests are in humans. They are also important in gaining information about a disease, how it manifests and the clinical course that it takes.
Drug development is not an expeditious process. For a new treatment to get from the idea stage to the pharmacy shelf it takes time, usually 10–15 years as the initial concept journeys through basic research, preclinical testing, clinical trials and finally regulatory approval.
This process is a costly one. A recent projection by the Tufts Center for the Study of Drug Development [2] puts the total cost for developing a drug at $2.9 billion. $1.4 billion of that amount going towards drug discovery and development costs with the remainder attributable to the loss of potential returns on investment and costs incurred following a drug’s approval.

Part of the problem, borne out in the survey results below, is the timely and successful recruitment of study subjects. As clinical trials have become more rigorous they have also grown larger and more complex, and the work burden for study staff is increasing. For those who choose to volunteer, the last decade has seen a more selective and more stratified approach to the inclusion and exclusion criteria applied to clinical trials. This narrowing of the goalposts by an estimated 58% is likely to be responsible for volunteer patient enrollment rates dropping by 21% and retention rates falling by 30%.

The challenges facing patient recruitment are complex, currently up to 30% of the timeline for the drug development process is spent on suitable subject enrollment. In fact, 45% of clinical studies are delayed because of difficulty enrolling participants. In an effort to evaluate why participation in Parkinson’s clinical research is so poor The Michael J. Fox Foundation for Parkinson’s Research conducted a poll in 2011. This revealed that even though more than 80% of respondents were at least “somewhat likely” to participate in a clinical trial, only one in ten Parkinson’s patients had actually taken part.

It seems there is a discordance between patient perceptions of the likelihood of their involvement and their actual participation in clinical trials. The identification of the cause of this disharmony provides the first step in developing appropriate strategies which could be employed to address these issues.                                                               

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A brief five question online survey was developed by Parkinson’s Movement, an international patient-driven action group created by The Cure Parkinson’s Trust. The survey was shaped with input from an advisory group of four Parkinson’s advocates, and two Parkinson’s specialist neurologists that run clinical trials. 
An invitation to participate was sent out to the charity’s database of people with Parkinson’s (consisting of 544 people who receive regular updates and 4,389 members of Parkinson’s Movement HealthUnlocked) along with most of the major UK speaking charitable organisations in the US and UK representing the interests of patients. Exact numbers invited are hard to estimate but likely exceed 10,000, placing response rates at 3% or lower.


A total of 303 people connected with Parkinson’s completed the survey. Of the 274 respondents that identified themselves, 197 (72%) were people with Parkinson’s, 41 (15%) were care partners, and 31 (11%) identified themselves as clinical researchers, neurologists or scientists (Fig. 1).
Scientists and other health professionals cited funding as a principal barrier to effective Parkinson’s trials (66%). The next biggest problem reported was the lack of administrative support and time available to manage the trial (46%). The third most common barrier to conducting an effective clinical trial identified was recruitment of people with Parkinson’s to specific studies (43%). Other highly cited issues affecting the clinical trial process were matters such as the lack of practical support from other organizations involved in the trial, and the patient community’s perceptions of the need for the trial and the importance of the subject matter (Table 1).
For patients and care partners, the top five reasons for not participating or engaging in clinical trials were varied. More than 56% cited potential adverse consequences and potential side effects of taking part in clinical studies as the most concerning barrier. 54% worried about the possible disruption to their normal medication regimen. Other principal barriers to patient involvement were the prospect of receiving a placebo instead of the active drug (38%) and the upheaval and inconvenience to life that the trial would cause (37%). The fifth most common concern cited by this group, was fear of not being kept fully informed of both the progress and results of the trial when appropriate.
When asked to recall the number of Parkinson’s clinical trials in which the respondents had participated, the vast majority stated between 0 and 5 (83%), followed by 9% having taken part in 6 to 10 studies. 4% of those surveyed participated in 11 to 20 and a small number, 5% , had taken part in more than 20 clinical trials (Fig. 2) – this equates to 13 responders of whom 4 were clinicians, 5 people with Parkinson’s and 5 were unspecified so could have answered the question in error. This question did not ask whether these were drug studies or not. This result needs to be seen in the context of the population sampled. In many respects this is likely to have constituted a highly motivated cohort. Moreover, it is unlikely that all trials are large-scale drug trials. Many may be much simpler trials, often not involving medication.


Success or failure of clinical trials is an area in which the patient body and scientific community have significant personal and professional interest. The results of this survey were presented at a meeting called Rallying to the Challenge in September of 2014 which was organised by VARI in association with Parkinson’s Movement. This meeting was attended by 100 people with Parkinson’s predominantly from the US and was organised specifically to discuss how people living with Parkinson’s can be a valuable resource in clinical trials. The highlights of the questionnaire served as a focus of discussion for those advocates, researchers, patients and care partners in attendance in an effort to develop tangible suggestions and calls to action, keeping in mind the overarching objective to improve the effectiveness of clinical trials in Parkinson’s disease.

Many of these issues can be mitigated by involving the patient community in all areas of treatment discovery and development.

The findings identified the most significant obstacles to carrying out effective clinical trials for those involved in conducting research as being lack of funding and support. In contrast for those with Parkinson’s, the principal barriers to their participation in medical research were found to be fear of potential adverse consequences, interruption of their ongoing medical regimen and concern about receiving placebos. This is in keeping with the perceived psychosocial barriers to clinical trial participation in the field of oncology where fear of side effects has been shown to be the most significant barrier to clinical trial participation as well. We feel that many of the principal barriers reported in this survey can be mitigated by the Parkinson’s community, as was discussed during Rallying to the Challenge. This may be achieved by focusing on the areas of communication, patient education, funding, recruitment and compliance throughout the clinical trial process. In fact, the importance of patient engagement in healthcare research has been shown previously to assist with increasing enrollment rates, securing funding for researchers, choosing study outcomes and designing research protocols.

It seems likely that the gap between the willingness of people living with Parkinson’s (pwP) to participate in clinical trials and the reality of the shortfall in recruitment numbers could be closed if there was better understanding, information and communication between those conducting the trials and the participants. This was the conclusion of the participants at the Rallying to the Challenge meeting – and as a result, a Charter encapsulating education, understanding and communication concerns has been developed by PwP. Much of the current divide between the Parkinson’s research and patient communities (and differing priorities as highlighted in the survey) is encapsulated by the problem of the lack of effective communication, an issue illustrated by other studies. The development of a clinical trial training programme that addresses misconceptions around the treatment development process, demonstrates best practice in patient engagement and identifies roles where those with Parkinson’s can become involved as partners in the process, could contribute significantly to engaging educated patients.

For patients, the charter highlights the key issues to consider when deciding whether or not to participate in a particular trial as well as direction to further resources for use both during and after their trial experience. It is also important to demonstrate to the wider Parkinson’s community that those with Parkinson’s can be a useful resource and have a role to play in accelerating clinical trials. The Parkinson’s community has value in identifying which trials are most relevant to them and in constructively engaging and contributing to the conduct of effective clinical trials; to learn from the experiences of current trial participants to help inform the conduct of future studies. Involvement of the patient community from the outset contributes to a culture of partnership and collaboration.

It is also important to demonstrate to the wider Parkinson’s community that those with Parkinson’s can be a useful resource and have a role to play in accelerating clinical trials.

A clinical trial in Plymouth, to evaluate the potential of simvastatin as a treatment for Parkinson’s, jointly funded by The Cure Parkinson’s Trust, Peninsula University and the J P Moulton Trust, is exploring and evaluating recruitment and retention strategies. The use of the Clinical Trials Charter in this trial will test its effectiveness as a tool for improved education and communication, and, in turn, better understanding, recruitment and retention i.e. employing the recommendations presented at Rallying to the Challenge. This will provide direct practical and experiential input into the process.


The drug development process is a long and arduous one, with many perceived and real barriers adding to its complexity. For researchers, lack of funding and support are cited as major barriers whereas for patients, the concern over side effects and perceived potential disruption of their ongoing medical management were the most influential determinants. Many of these issues can be mitigated by involving the patient community in all areas of treatment discovery and development. Parkinson’s Movement seeks to develop and deliver stronger partnerships between the research and patient communities, and in so doing, expedite the search for better treatments and ultimately a cure.


The document represents a consensus on the views expressed at the Rallying to the Challenge meeting. We thank the participants at that meeting for their contribution. We also thank Jean Burns (Parkinson’s Plan for Life), Helen Matthews (The Cure Parkinson’s Trust) and Leah Mursaleen (The Cure Parkinson’s Trust) for input, logistical support and critical review.

Source: 'Rising to the Challenges of Clinical Trial Improvement in Parkinson’s Disease' - Authors: Mathur, Soania | DeWitte, Steve | Robledo, Israel | Isaacs, Tom| Stamford, Jon

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