Singapore - Nine-month clinical results from the HEALING II study, presented during the Singapore LIVE congress by Dr Robbert de Winter (Academic Medical Center, Amsterdam, the Netherlands), indicate that a strategy of stent-based recruitment of endothelial progenitor cells (EPCs) is safe and effective, although success of the strategy may depend on patients having normal levels of circulating EPCs.

The EPC-capture strategy was devised to accelerate healing of endothelium damaged during stent delivery, a contributor to adverse outcomes following stenting. To this end, the Genous Bioengineered R-stent (OrbusNeich, Wanchai, Hong Kong) is coated with antibodies specific to bone-marrow-derived EPCs that circulate in the blood. Once "captured" on the stent surface, the EPCs flatten, mature into endothelial cells, and form a functional surface. Since delayed endothelialization, particularly with drug-eluting stents, is believed to be one of the causes of stent thrombosis, a strategy of EPC capture may accelerate healing and reduce risk of thrombotic events.

While no comparison arm was used in the HEALING II study, the clinical event rate at nine months was comparable to results seen in drug-eluting-stent trials for the treatment of similar types of lesions. As de Winter reported during Singapore LIVE, the target-lesion-revascularization (TLR) rate in the 63 patients who received the Genous stent was 6.3%, while the overall MACE rate was 7.9%. No subacute or late thrombosis occurred, despite only one month of dual antiplatelet therapy, de Winter reported.

Six-month angiographic results from HEALING II, presented by Dr Patrick Serruys (Erasmus University Hospital, Rotterdam, the Netherlands) at last year's TCT meeting, highlighted the importance of adequate endothelial-cell capture. Late loss in patients found to have low levels of circulating EPCs was more than double that of patients with normal circulating EPC levels (1.04 mm compared with 0.48 mm). MACE rates also trended higher in patients with lower circulating EPC titers. At the time, Serruys speculated that statin therapy, known to augment levels of circulating EPCs, might be an important way of optimizing results with EPC stenting.

"These low MACE and TLR rates [at nine months] are impressively more in the realm of results from drug-eluting-stent trials than those of bare-metal studies," Serruys commented in a company press release. "In addition, Genous's safety profile makes this an attractive option for treating patients at higher risk of thrombosis."