Micell Technologies Presents 3-Year Data From DESSOLVE Trials

September 16, 2014—Micell Technologies, Inc. announced 3-year clinical results from the DESSOLVE I and DESSOLVE II trials of the company’s MiStent SES, a sirolimus-eluting absorbable polymer coronary stent system. 

John Ormiston, MD, who serves as a Principal Investigator in the DESSOLVE studies, presented the data at the 26th Transcatheter Cardiovascular Therapeutics Conference in Washington, DC. William Wijns, MD, serves as Coprincipal Investigator for DESSOLVE I. Dr. Ormiston is an interventional cardiologist with the Mercy Angiography Unit in Auckland, New Zealand, and Dr. Wijns is with the Cardiovascular Center in Aalst, Belgium.

The company advised that the 3-year follow-up of the DESSOLVE I and II clinical studies was completed in 2014, and these patients will continue to undergo long-term follow-up. Micell received European CE Mark approval for the MiStent SES in June 2013, but it is not approved in the United States or any other countries. 

According to the company, the MiStent SES is designed to optimize vessel healing in patients with coronary artery disease. The data demonstrated desirable bare-metal stent–type healing. Normal endothelial function was maintained, and there was minimal progression of late lumen loss through 18-month follow-up. In addition, the DESSOLVE studies had an overall target lesion revascularization rate of 2%, with no probable or definite stent thromboses related to the MiStent SES at 3-year follow-up. 

The DESSOLVE I trial was the first clinical assessment of safety and efficacy of the MiStent SES and included 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. Patients were enrolled across five study centers in New Zealand, Australia, and Belgium. Three independent subgroups of 10 patients each were evaluated using angiography, intravascular ultrasound, and optical coherence tomography 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 the presence of strut coverage with tissue within the treated artery at each time point. 

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 the Endeavor Sprint DES (Medtronic, Inc.). This was 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 confirmed that DESSOLVE II met all study objectives, demonstrated a competitive in-stent late lumen loss rate, and achieved a strong signal of safety. 

Dr. Ormiston commented in Micell’s press release, “The MiStent SES is the sole product among the new generation of bioabsorbable polymer DES to sustain local drug delivery beyond the presence of the polymer, providing therapeutic sirolimus drug levels in the tissue surrounding the stent for up to 9 months. Full elimination of the polymer by 3 months—without loss of antirestenotic drug effects—is different from any other DES formulation.” 

The company noted that the MiStent SES system includes a stent coating that contains sirolimus and an absorbable polymer. The coating provides controlled and sustained release of therapeutic levels of drug as the polymer softens and disperses from the stent into the adjacent tissue. These properties are intended to enhance safety compared to conventional permanent polymer drug-eluting stents. The rapidly absorbable coating of the MiStent SES is intended to precisely and consistently control drug elution and limit polymer exposure duration, thereby reducing the safety risks associated with current commercially available drug-eluting stent technologies.