Drug-Coated Stents May Not Be Worth The Cost
Recent early release studies published in the New England Journal of Medicine have provided much needed evidence about the long-term use of drug-coated stents. Since their release in 2003, drug-coated stents have become the fastest selling medical devices in history. However, over the past few years, the safety and efficacy of these devices has been challenged due to emerging evidence that demonstrated a risk of stent thrombosis (blood clot within the stent). These concerns prompted the FDA to become involved and convene a meeting of its Circulatory System Devices Advisory panel in December 2006.
Two important factors emerged as contributors to apparent conflicts in stent data:
- “Variable definitions of stent thrombosis; and
- Key differences in the characteristics of patients and coronary lesions. “
These factors made it difficult to pool data for analysis and compare drug-coated stents to bare metal stents. In response, An Academic Research Consortium has proposed new criteria for classifying stent thrombosis. The other key issues affecting the performance and safety of drug-coated stents are the variable characteristics of patients and their coronary lesions. Approved indications, based on the pivotal trials for these devices, comprised non-complex patients with non-complex lesions. However, greater than 60% of drug-coated stents use is off-label (complex conditions and/or complex lesions).
A summary of the evidence from the New England Journal of Medicine articles follows (the studies will be published in print in the March 8, 2007 issue):
- “On-label use of stents is associated with persistent, long-term reduction in the need for revascularization (restoring the flow of oxygen and nutrients to the heart.
- The cumulative incidence of stent thrombosis at 4 years does not differ significantly between patients with drug-coated stents versus those with bare metal stents.
- Both approved drug-coated stents are associated with a small increase in stent thrombosis that emerges 1 year after implantation.
- When compared to bare metal stents, drug-coated stents were not associated with an increased rate of all-cause mortality.
- Registry data suggests that the rates of adverse events, including death, non-fatal MI and stent thrombosis are higher with off-label use compared to labeled use.
- Antiplatelet therapy recommendations (pdf) for drug-coated stents include aspirin therapy for life and clopidigrel for 3 to 12 months after implantation (current labeling recommends 3 months).”
In conclusion, drug-coated stents, considered a breakthrough technology, were granted an expedited review status. Although it is important to bring technologies that have a major impact on patient care to market in an expedited manner, adverse events may be more likely to occur. However, larger and longer post-marketing studies may help prevent similar issues in the future. There are remaining questions that will most likely be answered as additional studies are conducted. Considering that drug-coated stents are approximately 3 times the cost of bare metal stents, appropriate patient selection is prudent, and may reduce the risk of adverse events and help control costs associated with the use of these devices.
Related coverage: Drug-Coated Stents Not Always Best Option.
February 13, 2007 Related topics: Medical Devices & Products, Quality, Safety, Errors, Cardiology