Bridging Early Feasibility and Pivotal Trials: Insights From Transcatheter Tricuspid Valve Interventions

Early feasibility studies (EFS) are critical in the clinical development of high-risk cardiovascular devices, enabling first-in-human evaluation and iterative refinement prior to pivotal investigation. Regulatory frameworks supporting EFS have evolved substantially in the United States (US), while structured European pathways are emerging. This narrative review evaluates the evolution of the US EFS framework and examines its alignment with emerging European initiatives, using transcatheter tricuspid valve interventions (TTVI) as a representative case study.

Regulatory guidance documents, peer-reviewed literature, clinical trial registries (ClinicalTrials.gov), and publicly available sponsor disclosures published between 2013 and 2025 were reviewed. Three breakthrough TTVI technologies were analyzed: Abbott TriClip edge-to-edge repair, Edwards Lifesciences EVOQUE transcatheter tricuspid valve replacement, and P&F TricValve bicaval valve implantation. For each program, study design, patient population, sample size, treatment exposure, follow-up duration, safety and effectiveness outcomes, and regulatory progression were examined.

Early US cardiovascular EFS (2013-2016) typically enrolled 15 to 30 patients at ≤10 sites and focused on procedural feasibility and acute safety. Contemporary programs (2020-2025) enroll 50 to 200 patients across multinational sites and incorporate iterative device modification under structured Food and Drug Administration interaction. The TRILUMINATE EFS (TriClip; n = 98), TRISCEND I (EVOQUE; n = 176), and TRICAV-I (TricValve; n = 110) generated safety and performance data supporting transition to randomized pivotal trials. Breakthrough device designation facilitated regulatory engagement and staged evidence generation. CE marking was achieved earlier in Europe for all three devices, whereas US approval required randomized data and, in some cases, longer follow-up.

The US EFS program has evolved into a structured lifecycle development model enabling efficient progression from early feasibility to pivotal trials for first-in-class cardiovascular devices. Emerging European initiatives, including HEU-EFS and Medical Device Coordination Group 2025-9 guidance, indicate increasing transatlantic convergence toward harmonized early feasibility frameworks that balance innovation with patient protection.