Moving beyond intent: Building more diverse clinical trials
The importance of diversity in clinical trials is no longer a matter of debate. Across the pharmaceutical industry, sponsors, regulators, researchers, and patient advocates increasingly recognise that clinical trial populations should better reflect the communities that will ultimately use approved therapies. Representative enrolment is essential for understanding how treatments perform across different populations and for ensuring that new therapies are safe and effective.
Yet, despite widespread commitment to improving diversity, enrolment challenges persist.
The conversation today is no longer about whether diversity in clinical trials matters, but about how the pharmaceutical industry can progress towards achieving it. Sponsors must move beyond intention and focus on the practical and psychological barriers that continue to prevent participation among many patient populations.
Low enrolment is often not the result of a lack of willingness to participate. Instead, many patients face obstacles that make participation difficult, even when they are interested in joining a study. This has important implications for how sponsors approach recruitment, engagement, and trial design.
Willingness does not always translate into participation
For years, discussions around diversity in clinical research have often focused on recruitment and awareness. While awareness remains important, emerging research suggests that interest in participation may be higher than many assume.
A recent published study of ours, for example, found that a majority of respondents expressed willingness to participate in clinical trials. Importantly, this willingness included several populations that have historically been underrepresented in mainstream pharmaceutical research, including women, LGBTQ+ individuals, and Black participants.
Industry’s challenge is not simply convincing patients to participate. Rather, it is understanding why willing participants often do not enrol.
This shift in perspective matters. If patients are interested but unable to participate, recruitment efforts alone will not solve the problem. Sponsors must identify and address the factors that prevent participation in the first place.
Practical barriers continue to limit access
Clinical trial participation requires a significant investment of time, energy, and resources. Study visits, transportation requirements, follow-up appointments, and administrative tasks can create substantial burdens for participants.
According to the study, the time commitment was one of the most cited barriers to participation. Financial considerations, including travel expenses and the broader costs associated with participating in a study – such as the cost of missing a day’s paid work – were also frequently identified as obstacles. Furthermore, the study found that such challenges often extend beyond the financial costs of participating in a trial. Patients may need to take time away from work, arrange childcare, coordinate transportation, or secure support for dependent family members. For many individuals, particularly those already facing economic or logistical challenges, these requirements can make participation unrealistic.
As a result, traditional site-based trial models may unintentionally favour patients with greater flexibility, financial stability, and access to transportation, creating enrolment patterns that do not fully reflect the populations a treatment is intended to serve.
Addressing these barriers requires a broader view of accessibility. Financial reimbursement remains important, but it is only one component of a successful strategy. Flexible scheduling, transportation assistance, hybrid trial models, remote visits, and other participant-centred accommodations can significantly reduce participation burdens and improve access.
Making research more inclusive often begins with making participation more practical.
Psychological barriers remain a significant challenge
Practical barriers are only part of the equation. For example, our recent study also identified several psychological factors that can discourage participation. Fear of side effects emerged as the most frequently cited psychological barrier, While lack of knowledge about clinical trials and concerns about receiving a placebo were also frequently cited obstacles. However, this was more common among individuals who had never participated in a clinical trial compared to those with previous trial experience – suggesting fear may often be driven by uncertainty, rather than direct negative experiences with research.
These concerns are understandable. For many patients, clinical research remains unfamiliar. The enrolment process can feel complex, and uncertainty about what participation entails may create hesitation even among otherwise interested individuals.
Education therefore becomes a critical component of improving enrolment.
Patients need clear, accessible information about how clinical trials work, how participant safety is monitored, and what they can expect throughout the process. Recruitment materials should prioritise clarity and transparency, rather than relying on technical or highly scientific language.
Healthcare providers can also play a valuable role. Physicians remain one of the most trusted sources of information about clinical trials. Strengthening communication between healthcare providers and research teams can help patients feel more informed and confident when considering participation.
Trust is not built through a single recruitment campaign. It is built through consistent communication, transparency, and a patient experience that demonstrates respect for participants' concerns and questions.
Why data-driven recruitment matters
As enrolment challenges become increasingly complex, recruitment strategies must evolve accordingly.
Historically, many recruitment efforts have relied on broad awareness campaigns designed to reach as many patients as possible. While awareness remains important, a one-size-fits-all approach may overlook the specific barriers different populations face.
A working parent balancing childcare responsibilities may require different support than a rural patient who faces transportation challenges. A patient who is unfamiliar with clinical research may need educational resources, while another may need reassurance about safety monitoring and study procedures.
Data-driven recruitment approaches can help sponsors better understand these differences and tailor engagement strategies accordingly.
By leveraging patient insights, geographic data, digital engagement tools, and population-level analytics, sponsors can identify where barriers exist and develop targeted solutions that address them directly. Technology alone will not solve enrolment challenges, but it can help organisations better understand patient needs and design recruitment strategies that are more effective and inclusive.
The goal is not simply to reach more patients. It is to reach the right patients with the right support.
Diversity begins long before recruitment
Perhaps the most important lesson from recent research is that participant diversity should not be addressed for the first time during recruitment.
By the time recruitment begins, many of the factors that influence participation have already been determined. Protocol complexity, site selection, visit frequency, patient communications, and reimbursement policies all shape who can participate in a study.
When accessibility and inclusion are considered only after enrolment challenges emerge, sponsors may find themselves trying to solve problems that could have been addressed during study design.
Building more representative clinical trials requires planning for it earlier in the process and a more patient-centred approach. Sponsors should evaluate whether eligibility criteria are unnecessarily restrictive, whether study visits are realistic for participants, whether educational materials are accessible, and whether support services adequately address practical burdens.
The industry has made meaningful progress in recognising the importance of diversity in clinical research. The next phase of progress will depend on translating that commitment into action.
Improving representation is not simply about increasing awareness or setting enrolment targets. It requires identifying and removing the barriers that prevent willing patients from participating. By addressing both practical and psychological challenges, sponsors can create clinical trials that are more accessible, more inclusive, and ultimately more representative of the patients they aim to serve.
About the author
Shambhavi Chidambaram is the patient insights manager at Clariness, where she prepares pre-screeners for prospective participants of clinical trials. She comes from a strong academic background, having completed a PhD in Life Sciences, during which she also worked as a freelance science journalist. Chidambaram transitioned to the pharmaceutical industry four years ago, where she now applies her extensive background in data analysis, technical literacy, and science communication: designing and running pre-screeners, facilitating patient recruitment for clinical trials, and analysing their results. She also writes blogs drawn from the conclusions of her surveys and pre-screeners, aiming to make clinical trials more accessible and understandable, especially to marginalised communities. In her spare time, Chidambaram can be found hiking, running, swimming in lakes, or with her nose in a book to complete her annual reading challenge.
