Regulatory issues facing the development of drug-eluting stents: a US FDA perspective.
Coronary drug-eluting stents (DES) are a breakthrough technology that has changed the standard of care for many patients undergoing percutaneous intervention for coronary artery disease. Initial trials of two DES demonstrated significant clinical benefit with respect to the need for reintervention when compared with bare metal stents. However, more recent studies of DES involve in-patients with more complex disease, such as bifurcation lesions, chronic total occlusions and multiple-vessel disease. Additionally, DES are now being evaluated in patients previously only considered for surgical intervention. Assessment of DES in these complicated patient populations can lead to challenges in trial design, but the US FDA is willing to consider alternative clinical trial designs and statistical analysis plans. Other complex issues associated with DES include duration of clinical trials to determine safety, and the appropriate dose and duration of concomitant antiplatelet therapy. Finally, the FDA acknowledges that DES are complex products to produce and we believe that through interaction with the FDA during development, difficulties with test methodologies, animal studies and clinical trial designs can be addressed. The future of DES likely involves new stent and carrier materials, including biodegradable materials and new drugs and biologicals. The FDA anticipates continued collaboration with physicians, manufacturers, academic institutions and professional societies.