Cath Lab Digest

Medtronic: Danish Study, SORT OUT III, Looks at TLR, Stent Thrombosis for Endeavor® and Cypher® Stents

Medtronic, Inc. announced that the target lesion revascularization (TLR) rate for the company’s Endeavor® drug-eluting stent in the real-world Danish trial, SORT OUT III, was 4.0 percent. This result at nine months is consistent with the ENDEAVOR-Five real-world study, which reported an overall TLR of 4.5 percent at 12 months. The rates of myocardial infarction in the SORT OUT III study were very low for both the Endeavor (1.4 percent) and Cypher (0.5 percent) stents. The rate of stent thrombosis in SORT OUT III for Endeavor was 1.2 percent (ARC definition), consistent with typical rates of stent thrombosis for both drug-eluting and bare-metal stents after nine months of patient follow up.

Surprisingly, however, the SORT-OUT III study at nine months reported a 1.0 percent TLR rate for Cypher — considerably less than the 4.5 percent TLR reported in the similar SORT OUT II study, Galloem et al, JAMA 2008, previously conducted in the same five centers by the same group. In addition, the stent thrombosis rate for the Cypher stent was 0.2 percent, compared to 1.7 percent reported in the SORT OUT II study.

Dr. Jens Flensted Lassen, the study investigator, stated, “We were very surprised by these results — specifically those for Cypher and especially compared to the SORT OUT II data.” It was also noted during the presentation that late stent thrombosis becomes meaningful as a safety signal only after one year. Dr. Lassen commented on the safety outcomes in the study, which reported stent thrombosis for Endeavor of 1.2 percent at nine months: “This is only half the story, as we saw with ENDEAVOR IV, we expect late catch-up with Cypher.” Dr. Lassen’s comments acknowledge that while early events were also seen with Endeavor in the ENDEAVOR IV study at 12 months, there were no instances of late stent thrombosis with Endeavor after 369 days, in follow up to two years.

Medtronic soon will complete enrollment in the PROTECT clinical study. The PROTECT study is the largest randomized trial focusing on the safety of drug-eluting stents. This 8,800-patient trial is being conducted at 200 centers worldwide and will compare Medtronic’s Endeavor stent and Cypher, made by Cordis, using key safety endpoints and other clinically relevant outcomes. The primary endpoint for the PROTECT study will be overall stent thrombosis at three years.

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New Data Shows Abbott’s Bioabsorbable Drug-Eluting Stent Is Absorbed Within Two Years, Leaving Behind Functioning Blood Vessels

Abbott announced two-year data from 30 patients in its ABSORB clinical trial, demonstrating that its bioabsorbable drug-eluting stent successfully treated coronary artery disease and was absorbed into the walls of treated arteries within two years, leaving behind blood vessels that appeared to move and function similar to unstented arteries. Patients who received Abbott’s bioabsorbable drug-eluting coronary stent and were followed out to two years experienced no stent thrombosis out to two years and no new major adverse cardiac events (MACE) between six months and two years. These results confirmed earlier positive one-year clinical results with Abbott’s bioabsorbable drug-eluting stent. The results were presented at the Cardiovascular Research Foundation’s 20th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium.

“Now you see it, now you don’t — for the first time, we have data in patients showing that Abbott’s bioabsorbable drug-eluting stent does its job treating diseased coronary arteries and that it is absorbed by two years,” said John Ormiston, MD, principal investigator in the ABSORB trial and medical director at Mercy Angiography in Auckland, New Zealand. “Clinical safety and effectiveness were sustained at two years, and the previously stented portion of arteries demonstrated the ability to expand and contract in a manner similar to a vessel that has never been stented.”

Trends were observed in data from tests of artery movement and function, demonstrating a potential restoration of unstented artery movement to coronary blood vessels after the stent was absorbed.

Abbott also presented intravascular ultrasound (IVUS) and optical computed tomography (OCT) imaging data on its bioabsorbable drug-eluting coronary stent platform at TCT in the “Best of Coronary Interventions Abstracts.” IVUS data revealed a decrease in plaque area in treated arteries corresponding to a similar increase in blood flow area between six months and two years: 12.7 percent decrease in plaque area (p≤0.001, n=17); 10.8 percent increase in luminal area (p=0.03, n=17). OCT imaging data showed absorption of the stent into artery walls and that the blood vessel lining of arteries treated with Abbott’s bioabsorbable stent looks more uniform after two years than it did immediately post-treatment.

“The imaging technology data from the ABSORB trial indicate that Abbott’s bioabsorbable stent has the potential to restore vascular integrity and endothelial function to treated vessels after two years,” said Professor Patrick W. Serruys, MD, PhD, professor of interventional cardiology at the Thoraxcentre, Erasmus University Hospital, Rotterdam, and co-principal investigator in the ABSORB trial. “With these ABSORB data, we have come full circle in interventional time, linking the past, when balloon angioplasty was used without stents, to the future, when disappearing stents may become the new standard of care for patients with coronary artery disease.”