Biodegradable polymer-based and polymer-free rapamycin-eluting stents have a 1-year safety profile similar to that of the Cypher stent. In a comparison trial, both the biodegradable, polymer-based, and polymer-free, rapamycin-eluting stents were found to be at least as effective as Cypher.

“It remains to be investigated whether the absence of a permanent polymer is associated with an improved outcome at longer term,” said Julinda Mehilli, MD, of Technische Universitat in Munich, Germany.

ISAR-TEST-3

In the ISAR-TEST-3 trial a comparison of the antirestenotic efficacy of biodegradable polymerbased and polymer-free rapamycineluting stents vs. the Cypher (Cordis, Johnson & Johnson) stent, researchers reported comparable rates of late lumen loss in all three stents (P <0 .001for non-inferiority, Figure).

Angiographic restenosis was 9% and clinical restenosis was 5.9% for the biodegradable stent; 16.9% and 12.9%, respectively, for the polymer-free stent; and10.8% and 7.9%, respectively, for the Cypher stent these differences were not statistically significant.

Four patients in each group died (P = .70). Definite/probably/possible stent thrombosis occurred in 1% of patients treated with the biodegradable polymer-based stent; 1.5% of patients treated with the polymer-free stent; and 2% of patients treated with the Cypher.

Jeffrey Popma, MD, said ISARTEST-3 was an important study, with good angiographic follow-up. In-stent late loss was suitable as an endpoint, he said, and was the best measure for the degree of intimal hyperplasia within the stent. He said larger clinical studies examining safety and clinical efficacy are warranted for both biodegradable and polymer-free rapamycin-eluting stent systems.