Orbit II coronary trial completes patient enrolment


Cardiovascular Systems has announced it has completed enrolment in its ORBIT II clinical trial with 443 patients. ORBIT II is evaluating the safety and effectiveness of the company’s orbital atherectomy technology in treating severely calcified coronary arteries.

It is estimated that moderate to severe arterial calcium is present in nearly 40% of those treated annually for coronary artery disease (CAD). According to the company, ORBIT II is the first premarket approval trial designed to study these difficult-to-treat patients.

“Completing ORBIT II enrolment is a significant milestone in our efforts to secure a coronary indication to treat arterial calcium—a vastly underestimated problem in medicine today,” said David L Martin, president and chief executive officer, Cardiovascular Systems. “At TCT this year, Dr Philippe Genereux presented new data proving, with statistical significance, that patients with moderate to severe calcium were more likely to die, and have major adverse coronary events–results Dr Genereux described as ‘shocking.’”

The data presented at TCT by Genereux, director of the Angiographic Core Laboratory at the Cardiovascular Research Foundation, was from 14 randomised trials and included 11,651 treated with drug-eluting stents. While almost all of the studies were designed to exclude patients with moderate to severe calcium, nearly 21% of the patients enrolled actually had that level of calcium as confirmed by an independent angiographic core laboratory. Results from this patient subset showed statistically higher rates of death and major adverse cardiac events (MACE), including myocardial infarction, definitive stent thrombosis or ischaemic target lesion revascularisation, than patients with no or mild calcium.

Jeffrey Chambers, interventional cardiologist, Metropolitan Cardiovascular Consultants, Minneapolis, USA, and principal investigator for the ORBIT II study, said: “Despite advanced stent technology, moderate to severe calcification remains a real challenge for interventional cardiologists, and new therapeutic approaches are needed. Based on promising results in treating severely calcified coronary arteries in the ORBIT I study, CSI’s orbital technology may be well suited for removing calcified plaque in coronary lesions. I look forward to seeing the results from ORBIT II and I am hopeful that we will have a new therapy in the near future for these difficult-to-treat patients.”

Cardiovascular Systems received FDA investigational device exemption approval for the ORBIT II study in April 2010, and more than 45 US medical centres enrolled patients. The primary endpoints of ORBIT II are based on a 30-day patient follow-up post procedure. Of the 443 patients enrolled in ORBIT II, 343 were treated with the company’s original pneumatic orbital atherectomy system (OAS) and 100 with the company’s new electric OAS.

According to the company, the new electric coronary OAS offers a simpler design that gives physicians complete control of device operation, with minimal set up time. Cardiovascular Systems and the FDA agreed to a modular pre-market approval submission. To date, modules 1 (preclinical) and 2 (manufacturing/system quality) have been submitted to the agency and are currently under review. The company’s pre-market approval will be final on submission of module 3 which includes ORBIT II clinical data and proposed labeling. Cardiovascular Systems anticipates that this will occur in early 2013.