Silk Road Medical announces 30 day results in the Roadster clinical trial for carotid artery revascularization

Sunnyvale, CA. -- Silk Road Medical, Inc. announced the 30 day outcomes from the ROADSTER IDE Study at the VIVA 2014 Vascular Interventional Advances Annual Conference in Las Vegas, Nevada. The trial studied the treatment of carotid artery stenosis with a new device and hybrid procedure combining the best elements of carotid endarterectomy (CEA) and carotid artery stenting (CAS).  The device under study is the ENROUTE™ Transcarotid Neuroprotection System (NPS) (Silk Road Medical, Inc., Sunnyvale, CA) which is designed to provide direct access to the carotid artery and reduce the risk of stroke during CAS by diverting dangerous debris away from the brain with a surgically-inspired mechanism to temporarily reverse blood flow.  

Celebrating its 60th anniversary in 2013, CEA has been the “Gold Standard” in carotid artery revascularization because of the low stroke and death rates in multiple prospective trials, registries, and administrative databases.  Yet CEA is not free of the potential for certain local and systemic complications such as cranial nerve injury and myocardial infarction. The potential for such complications increases in patients with high risk anatomic or physiologic characteristics. .

Fifteen years ago transfemoral CAS with embolic protection was introduced with much initial excitement due to the minimally invasive, endovascular advantage, but fell out of favor for physicians and payors due to the excess risk of peri-procedural stroke compared to CEA.  In a standard surgical risk population, CREST demonstrated peri-procedural strokes occur twice as often in CAS patients.

"With direct carotid access and robust flow reversal, the ENROUTE Transcarotid NPS solves for the excess stroke risk of CAS resulting from catheterization of the arch and inadequate neuroprotection, while enabling a simplified, less invasive method for treating the culprit lesion than CEA." said Dr. Sumaira Macdonald a leading expert in the field of carotid artery disease and the Company's Chief Medical Officer. 

ROADSTER was a prospective, multi-center, IDE study designed to evaluate the safety and effectiveness of the ENROUTE Transcarotid NPS.  Richard Cambria, MD and Christopher Kwolek, MD of Massachusetts General Hospital served as the trial Co-Principal Investigators.  Patients were enrolled at 15 vascular surgery sites, one neurosurgery site, and two multi-specialty sites. The primary endpoint was a composite of Any Stroke (S), Death (D), or Myocardial Infarction (MI) through 30 days.

Symptomatic and asymptomatic patients who were at high risk for complications from CEA were eligible. Between November 2012 and July 2014, 208 patients (67 lead-in, 141 pivotal) were enrolled. FDA-approved carotid stent systems, chosen according to site preference, were delivered through the direct carotid access point under high rate flow reversal afforded by the ENROUTE Transcarotid NPS.  Baseline pivotal population characteristics included 26% Symptomatic, 35% Female, and 47% Age ≥75. 

30-day S/D/MI, S/D, and Any Stroke were 3.5%, 2.8%, and 1.4%, respectively, in the Intention to Treat (ITT) population.  In a Per Protocol (PP) analysis (n=136), the outcomes were 2.9%, 2.2% and 0.7%, respectively. There were no strokes in patients Age ≥75 nor in Symptomatic patients. There was one (0.7%) CNI presenting as hoarseness which fully resolved. 

“These stroke rates in a high surgical risk population are the lowest to date for CAS and comparable to the peri-procedural rates in the standard surgical risk CEA arm of CREST (2.3%).  The Silk Road procedure is less of an operation for the patient than a traditional CEA and can be performed in under an hour with local anesthesia.  With more experience and evidence, vascular specialists can look forward to incorporating this procedure as a true alternative to CEA for patients.” commented Dr. Cambria.

Erica Rogers, CEO for Silk Road Medical, commented, “The ROADSTER data support our hypotheses that led to this device design and procedure.  It’s all about stroke.  Doctors perform these procedures to reduce the risk of stroke, not to cause a stroke.  The ENROUTE Transcarotid platform finally delivers a less invasive alternative with the neuroprotection you would expect from a CEA procedure.”

About the ENROUTE Transcarotid platform

The ENROUTE Transcarotid NPS and the ENROUTE Transcarotid Stent System have been granted CE Mark. The ENROUTE NPS and Stent Systems are limited by United States law to investigational use; the ENROUTE Transcarotid NPS has been submitted for 510(k) review and the ROADSTER trial will also support a Premarket Approval application (PMA) for the ENROUTE Transcarotid Stent System.

About Silk Road Medical

Silk Road Medical, Inc. is a private company located in Sunnyvale, CA, that develops and manufactures less-invasive medical devices intended to improve the treatment of intra- and extra-cranial cerebrovascular disease through proprietary transcarotid access platforms.  Detailed information about Silk Road Medical can be found at www.silkroadmed.com.