Strengthening the evidence base for precision medicine through the utilization of real-world data and real-world evidence: a narrative review from the U.S. perspective.

The expansion of precision medicine has shifted toward individualized care tailored to a patient's genetic profile. While randomized controlled trials (RCTs) remain the gold standard for establishing efficacy, they often struggle to reflect the phenotypic diversity of patients in routine clinical practice. This paper explores the role of Real-World Data (RWD) and Real-World Evidence (RWE) in bridging this translational gap. A structured literature search identified peer-reviewed articles examining RWE applications in identifying rare genetic targets, informing clinical trial design, and supporting U.S. Food and Drug Administration (FDA) regulatory decisions. This review synthesizes recent regulatory advances through early 2026, including frameworks supporting the use of aggregated RWD that expand large-scale, multi-institutional evidence generation. RWE provides a scalable mechanism for identifying rare genetic variants and validating biomarker-driven therapies across heterogeneous patient populations while enabling longitudinal assessment of natural disease history and treatment safety. Operational successes in oncology, transplant medicine, and rare diseases demonstrate regulatory acceptance of RWE alongside critical challenges in data standardization, interoperability, and bias mitigation through causal inference frameworks, including target trial emulation. RWD and RWE serve as necessary complements to RCTs, providing the hybrid evidentiary framework needed to realize precision medicine's potential.