Standards Needed to ID Patients at Risk for Thrombosis
European researchers say their studies illustrate a need for transparency in drug-eluting stent safety trials.
Two researchers yesterday called for longer-term follow-up data and standardized protocols to help physicians identify which patients may be at an elevated risk for late-onset thrombosis following the placement of drug-eluting stents.
Edoardo Camenzind, MD, of University Hospital in Geneva, Switzerland, and Matthias Briel, MD, with the Basel Institute for Clinical Epidemiology in Switzerland, said that more research is needed because there is a difference between what may be witnessed in clinical trials and what is taking place out in the “real world.”
The biggest difference, researchers note, is that patients with more complicated lesions are stented with DES, leading to higher complication rates in those patients.
Data presented in Europe
Camenzind reviewed the data that he presented at the 2006 World Congress of Cardiology that was based on an analysis of trials of the Cypher (Cordis, Johnson & Johnson) and Taxus (Boston Scientific) drug-eluting stents. Camenzind and colleagues compared those outcomes with bare-metal stent controls, finding an increased rate of late coronary thrombosis and an escalated risk of MI and death in those patients who received drug-eluting stents (Figure 1).
Data from Briel and colleagues that were also presented in Europe suggested that drug-eluting stents did not reduce total mortality when compared with their bare-metal stent counterparts (Figure 2), and that sirolimus-eluting stents may lead to increased noncardiac mortality.
Even though it is widely known that drug-eluting stents reduce the need for revascularization procedures, little is known about the effect of these trends beyond one year after the stents are implemented, Briel said.
In a meta-analysis, his group evaluated total, cardiac and noncardiac mortality rates in randomized controlled trial that compared sirolimus- or paclitaxel-eluting stents.
Seventeen trials were included in their analysis; of these, only two had data out to four years, nine out to three years and 12 out to two years. All 17 had one-year follow-up.
Researchers found a trend toward increased mortality with drug-eluting stents over time, but the differences between drug-eluting stents and bare-metal stents were not statistically significant. Noncardiac deaths were attributed to cancer, stroke and lung diseases, he said.
Transparency needed
Since these findings were reported, Camenzind said, there has been an increased emphasis on “transparency” in clinical trials. Officials with Boston Scientific and Johnson & Johnson have contacted Camenzind and are providing data for a future analysis, which he said would likely be released soon.
In a press conference following the presentations, Gregg W. Stone, MD, said that although the European data clearly illustrated a need for transparency in trials, a structure should be in place for dissemination of the data.
Having it too easily available could mean a competitive disadvantage for the drug manufacturers, Stone said.
