Two-Year Follow-Up Data for MiStent SES Presented

October 28, 2013—Micell Technologies, Inc. (Durham, NC) announced the presentation of imaging and clinical results from the DESSOLVE I and DESSOLVE II trials of the MiStent SES, the company's sirolimus-eluting, absorbable polymer coronary stent system. John Ormiston, MD, a principal investigator in the DESSOLVE studies, presented the 2-year follow-up data from the DESSOLVE I and II trials at the TCT 2013: Transcatheter Cardiovascular Therapeutics conference in San Francisco, California. Dr. Ormiston is an interventional cardiologist with the Mercy Angiography Unit in Auckland, New Zealand.

The MiStent SES is a thin-strut drug-eluting stent that features a rapidly absorbable coating designed to control drug release. It was developed to optimize vessel healing in patients with coronary artery disease.

According to Micell Technologies, the DESSOLVE I trial demonstrated minimal progression of late lumen loss between 8 and 18 months of follow-up with no target lesion major adverse cardiovascular events (MACE) through 2 years. The DESSOLVE II randomized trial's 2-year MACE rates were 6.7% for MiStent and 13.3% for the control group treated with the Endeavor Sprint drug-eluting stent (Medtronic, Inc., Minneapolis, MN).

There were no probable or definite stent thromboses related to MiStent use observed in either trial through 2 years. Detailed intravenous ultrasound (IVUS), angiographic, and optical coherence tomography (OCT) imaging with endothelial function testing conducted across the two trials demonstrated bare-metal-stent–type healing with maintenance of normal endothelial function.

In the company's press release, Dr. Ormiston commented, “MiStent is the only product in its class to optimize local drug delivery properties by providing up to 9 months of drug presence with only 3 months for polymer absorption. Because the drug persists three times longer than the polymer, MiStent eliminates the inflammatory effect of the polymer quickly and retains the anti-inflammatory and antirestenotic drug 6 months beyond the presence of the polymer.”

Micell Technologies described the DESSOLVE I trial as the first clinical assessment of safety and efficacy of the MiStent SES. In the study, investigators treated 30 patients with de novo lesions in coronary arteries ranging in diameter from 2.5 to 3.5 mm and amenable to treatment with a maximum 23-mm-length stent. The patients were enrolled across five study centers in New Zealand, Australia, and Belgium. Three independent subgroups of 10 patients each were evaluated using angiography, IVUS, and OCT at three time points: 4, 6, and 8 months. The primary efficacy endpoint was in-stent late lumen loss. Safety was assessed by incidence of MACE and presence of strut coverage with tissue within the treated artery at each time point. William Wijns, MD, of the Cardiovascular Center in Aalst, Belgium, and Dr. Ormiston are coprincipal investigators for this trial.

The DESSOLVE II CE Mark trial is a randomized, multicenter study of patients with documented stable or unstable angina pectoris. The primary endpoint is superiority of the MiStent SES in minimizing in-stent late lumen loss at 9 months compared to Medtronic's Endeavor Sprint drug-eluting stent, as measured by an independent angiography core laboratory in de novo coronary lesions in vessels ranging in diameter from 2.5 to 3.5 mm and amenable to treatment with a maximum 30-mm length stent. The DESSOLVE II study completed enrollment of 184 patients in July 2011. Data analysis confirms that DESSOLVE II met all study objectives, demonstrated a competitive in-stent late lumen loss, and achieved strong signal of safety, reported the company.

The company noted that data presented at TCT were also included in DESSOLVE I's 18-month results that were published recently by Dr. Ormiston, et al in the Journal of the American College of Cardiology: Cardiovascular Interventions (2013;6:1026-1034). The investigators concluded that at 18 months of follow-up, the MiStent SES was associated with a low and stable in-stent late lumen loss, complete strut coverage, and no stent thrombosis. Cardiac Interventions Today's news coverage of the published study is available online.

Micell was granted European CE Mark approval for MiStent SES in June 2013, but the device is not approved in the United States or any other countries. A 2-year follow-up of DESSOLVE I and II patients was completed in 2013, and these patients are currently undergoing long-term follow-up.