The integration of clinical and real-world evidence represents one of the most critical transformations in modern drug development and health technology assessment (HTA). Despite increasing regulatory openness, however, clinical trial evidence and real-world data (RWD) still operate largely as parallel rather than fully complementary systems. This commentary argues that experimental and observational research are not competing paradigms but two interdependent components of a unified evidence ecosystem, each capturing distinct yet equally essential dimensions of patient reality. Randomized controlled trials (RCTs) typically enrol highly selected populations and are optimised for internal validity, whereas RWD reflect the heterogeneity, comorbidities, and lived experiences of patients in routine clinical practice. Integrating these two evidence streams is therefore fundamental for personalised medicine, where the objective is to generate evidence that is both scientifically rigorous and meaningfully reflective of individual patient needs. This narrative Policy Practice Commentary synthesises regulatory guidance, methodological literature, and applied case examples to examine how leading regulatorsand HTA agencies, including the U.S. Food and Drug Administration (FDA), European Medicines Agency (EMA), Medicines and Healthcare products Regulatory Agency (MHRA), Pharmaceuticals and Medical Devices Agency (PMDA), and National Institute for Health and Care Excellence (NICE), are developing frameworks to support the use of RWD and real-world evidence (RWE) in regulatory approval and reimbursement decision-making. Areas of convergence and divergence are explored, with particular emphasis on methodological transparency, data provenance, causal inference, and reproducibility as shared quality anchors across jurisdictions. Illustrative case examples from oncology and ophthalmology are used to demonstrate both the opportunities and challenges of hybrid evidence generation. In oncology, RWD are increasingly applied in external and hybrid control arms, pragmatic designs, and post-authorisation safety and effectiveness studies. In ophthalmology, advances in artificial intelligence-enabled image analytics and disease registries illustrate how routinely collected clinical data and patient-reported outcomes can be integrated to inform real-world value assessment. The commentary concludes by proposing actionable policy and practice recommendations to operationalise integrated evidence models, focusing on harmonised governance and methodological standards, transparent reporting and cross-sector collaboration, systematic incorporation of patient-generated data, and incentives for early and lifecycle-oriented RWD generation. By aligning regulatory policy, analytical methodology, and patient-centred design, integrated RWE frameworks can support decisions that are both scientifically robust and genuinely reflective of real-world patient experience.
Alexandros Sagkriotis (Fri,) studied this question.