One-year target vessel failure outcomes with the use of a bioabsorbable polymer-based drug-eluting stent (DES) with a luminal CD34+ antibody coating (COMBO stent) compared with using a durable polymer-based DES (Traditional stent) met the non-inferiority boundary, said researchers presenting the HARMONEE trial at TCT 2017 in Denver.

The trial, a collaboration between U.S. and Japanese regulatory authorities, clinical sites and manufacturers, randomized 572 patients with coronary artery disease from 33 sites in Japan and 17 sites in the U.S. to either the COMBO stent or the Traditional stent. The primary endpoint was target vessel failure at one year, with the primary mechanistic endpoint being one-year healthy tissue strut coverage by optical coherence tomography (OCT).

Overall results found no safety concerns with the COMBO stent, however, the study assay sensitivity criterion was underpowered and not met due to the very low target vessel failure rates (4.2 percent vs. predicted 9 percent). Additionally, study investigators noted that OCT "suggests an active mechanistic role of endothelial progenitor cells (EPC) technology in vivo," given the superior healthy tissue strut coverage in the COMBO group, compared with the Traditional DES group, as well as the more homogenous tissue qualitatively with the COMBO stent vs. Traditional stent.

"This is a small study with limited follow-up," notes ACC.org Editor-in-Chief Kim Eagle, MD, FACC. "While these findings are hypothesis generating, they are far from conclusive."

On a separate, but related, note study investigators suggested that the international collaborative nature of the study offers a "unique platform for investigational devices studies" and could prove beneficial for other similar studies in the future.

Keywords: Coronary Artery Disease, Polymers, Absorbable Implants, Antibodies, TCT17, Transcatheter Cardiovascular Therapeutics

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