A Medical Device Daily

Angiotech Pharmaceuticals (Vancouver, British Columbia) reported positive preclinical data related to its Vascular Wrap paclitaxel-eluting mesh and Lifespan graft technology at theWestern Vascular Society 2006annual meeting at La Jolla, California.

“We are excited by the potential of the Vascular Wrap paclitaxel-eluting mesh product in a variety of indications, including AV access for hemodialysis patients,” said William Hunter, Angiotech president/CEO.

Although synthetic grafts are currently used in about 40% of hemodialysis patients who require permanent vascular access, primary patency rates remain poor. Most graft failures are caused by scar tissue growth inside the graft (neointimal hyperplasia) at the location where the graft is connected to the vein (the graft-vein anastomosis). Currently, about 50% of grafts fail within one year and about 75% within two years as a result of scar formation, according to Angiotech.

This preclinical study was designed to evaluate the effect of the Vascular Wrap bioabsorbable mesh containing paclitaxel on inhibiting neointimal hyperplasia in an animal model of dialysis access failure, said Angiotech. In this study, neointimal hyperplasia was reduced by a minimum of 87.6% in animals that received a paclitaxel-eluting mesh compared with animals that received no mesh.

Ted Kohler, MD, of the Veterans Affairs Puget Sound Health Care System (Seattle), is the principal investigator of this study. Kohler reported that commercially available grafts were surgically placed between the left common carotid artery and right external jugular vein in 40 animals, which were randomized to receive either no mesh or a 3 cm by 6 cm mesh placed around the graft-vein anastomosis containing one of four doses of paclitaxel [0.0, 0.3, 0.7 or 1.2 (micro)g/mm2].

Animals in both control groups developed significant neointimal hyperplasia at the cross-section taken perpendicular to the graft at its most distal end: 10.5 +/- 6.8 mm2 and 6.4 +/- 3.2 mm2 in the no mesh and zero-dose mesh groups, respectively. Compared with the zero-dose mesh group, neointimal area was significantly reduced in all paclitaxel mesh groups: 0.9 +/- 1.4 mm2, 1.3 +/- 1.5 mm2 and 1.2 +/- 1.4 mm2 in the three dose groups, respectively. There was no significant effect of the paclitaxel mesh on healing of the anastomosis or on the thickness of the adjacent vein.

“We are encouraged by the results of our preclinical data, and believe that we may be able to offer a better treatment option for hemodialysis patients,” said Dr. Rui Avelar, chief medical officer of Angiotech. “These results, complemented by the extensive experience with paclitaxel in cardiovascular applications, have given us further confidence as we look to start our clinical studies in hemodialysis access.”

In August, Angiotech reported its intent to launch a clinical trial in the United Kingdom to determine if hemodialysis patients who receive the Vascular Wrap paclitaxel-eluting mesh/Lifespan graft experience fewer graft failures than those that receive the graft alone. Angiotech expects to enroll the first patient in the UK-based clinical trial this fall. The company also intends to conduct a similar trial in the U.S. Both trials are expected to be about 24 months in duration, with enrollment taking about a year. The goal of the studies is to provide Angiotech with sufficient data to submit to regulatory authorities for the approval to market the products in the U.S. and Europe.

Angiotech develops treatments for diseases or complications associated with medical device implants, surgical interventions, and acute injury.