Study design and protocol development
The EU and US differ in their approach to study design and protocol development, and these differences have real consequences for how trials are executed across borders.
In the EU, guidelines provided by the European Medicines Agency (EMA) promote consistency across member states. This harmonization can simplify multi-country submissions within Europe, but it also means sponsors must design protocols that satisfy a shared framework rather than adapting to a single national authority.
In the US, the Food and Drug Administration (FDA) serves as the sole federal regulatory body, which gives sponsors more flexibility to design trials tailored to their specific needs. However, this flexibility can introduce complexity when the same protocol must also meet EMA requirements.
Both regions prioritize scientific rigor, patient safety, and ethical standards. But for sponsors running trials across both markets, the challenge is designing a single protocol that satisfies both regulatory frameworks without introducing unnecessary complexity. As study designs grow more intricate, particularly in precision medicine where eligibility criteria may depend on genetic or biomarker data, the downstream effects of protocol decisions on recruitment feasibility and operational execution become more pronounced.
Patient recruitment
Patient recruitment is frequently the most operationally challenging phase of a clinical trial. Delays in finding and enrolling participants extend timelines and increase cost, often more than any other single factor.
The EU and US present structurally different recruitment environments. In the EU, many member states have public or semi-public healthcare systems with centralized patient records, which can facilitate identification and referral of potential participants. However, healthcare infrastructure varies significantly across EU countries, and sponsors should not assume uniform access or referral pathways across the region.
In the US, the healthcare system is more fragmented. A significant proportion of trial participants are already patients at the recruiting site, which means that site selection directly shapes enrollment capacity. Beyond site-based referrals, US sponsors rely heavily on digital channels, patient registries, and advocacy partnerships to reach new populations.
For multi-region programs, these differences mean that a single recruitment strategy is unlikely to work across both markets. Channel mix, referral workflows, and the role of the clinical site in patient identification all need to be adapted to regional infrastructure. This is particularly important in precision medicine trials, where eligible patient populations may already be small and geographically dispersed.
Prescreening
Prescreening is the process of evaluating potential participants against eligibility criteria before formal enrollment. It is a critical step for narrowing large populations down to qualified candidates, particularly in trials with complex inclusion and exclusion criteria.
In the EU, prescreening may involve accessing centralized healthcare databases or collaborating with healthcare professionals to identify suitable candidates. The availability of structured health data in many EU countries can make it possible to assess eligibility at scale before patients are ever contacted.
Conversely, in the US, the Health Insurance Portability and Accountability Act (HIPAA) imposes strict regulations on the use and sharing of patient data. This means sponsors must navigate privacy requirements and obtain informed consent before accessing medical records for prescreening. As a result, US prescreening workflows often rely more heavily on patient self-reported data, digital questionnaires, and online screening tools to assess preliminary eligibility before clinical confirmation.
In both regions, the challenge is compounded by the fact that many potential participants have never considered clinical trials as part of their care journey. This means prescreening strategies must not only filter for eligibility but also reach and educate patients who may not be actively seeking research participation. For precision medicine trials, where prescreening may include genetic or biomarker assessment, these workflows become even more complex and region-specific.
Informed consent
Obtaining informed consent is essential to protect participants' rights and ensure ethical conduct. How consent is structured and delivered also directly influences a participant's willingness to enroll, making it both a regulatory requirement and a practical factor in recruitment success.
In the EU, consent processes often follow the principles outlined in the EU Clinical Trials Regulation. This involves providing clear trial information to participants and obtaining written consent before enrollment.
In the US, consent processes for medical research studies are governed by the Code of Federal Regulations (CFR), specifically Title 45, Part 46, also known as the “Common Rule.” The US consent process typically involves more extensive documentation.
For instance, when enrolling participants in a clinical trial, researchers must provide detailed information including:
- Study purpose and procedures
- Potential risks and benefits
- Alternative treatments
- Confidentiality measures
- Financial considerations
Cultural differences across regions can also influence how participants interpret and respond to the consent process. In multi-region trials, researchers should tailor consent language, format, and delivery to align with local expectations while maintaining regulatory compliance. This is particularly relevant in precision medicine trials, where consent may need to address genetic data collection, storage, and potential reuse.
Patient engagement
Engaging patients throughout the clinical trial process is essential for retention and overall trial success. When engagement falters, participants drop out, timelines extend, and the cost of recovering lost enrollment compounds. This makes engagement not just a communication exercise but an operational imperative tied directly to whether a trial meets its enrollment targets.
In the EU, patient engagement efforts are often anchored by patient advocacy groups, which play a significant role in trial design, information dissemination, and community trust-building. These organizations frequently serve as intermediaries between sponsors and patient populations, particularly in rare disease programs.
In the US, advocacy groups also contribute, but patient engagement is additionally driven by institutional initiatives like the Patient-Centered Outcomes Research Institute (PCORI), which promotes patient involvement in research decision-making. US engagement strategies also tend to rely more heavily on digital channels, participant portals, and direct-to-patient communication.
Both regions recognize the value of sustained patient engagement, but the mechanisms differ. For sponsors running multi-region programs, this means engagement strategies cannot be standardized across the EU and US without accounting for differences in community infrastructure, communication norms, and the role of advocacy organizations in each market.
Conclusion
The EU and US clinical trial markets differ in meaningful, structural ways across study design, recruitment infrastructure, prescreening workflows, consent frameworks, and engagement models. These are not surface-level variations. They shape how trials are planned, how patients are found, and whether enrollment targets are met.
For sponsors running multi-region programs, treating these differences as implementation details rather than strategic inputs leads to misaligned workflows, inconsistent patient experiences, and avoidable delays. The more complex the trial, particularly in precision medicine where genetic eligibility adds additional layers of regional variability, the more these differences compound.
Understanding EU and US nuances is a starting point. Translating that understanding into coordinated recruitment, prescreening, and engagement strategies across regions is what determines whether a trial delivers on its timeline.
Conclusion
For sponsors managing trials across the EU and US, the challenge is not simply understanding regional differences but building operational workflows that account for them. Sano Genetics provides a unified platform for recruitment, genetic testing, and long-term engagement that is designed to work across borders, with the flexibility to adapt prescreening, consent, and engagement strategies to regional requirements.
To learn more about how Sano supports multi-region precision medicine programs, visit our Sponsors page or get in touch.