Medical Device Daily Executive Editor
The halt of a clinical trial can be either bad news — because clearly not meeting endpoints and perhaps even hurting patients — or, with endpoints obviously accomplished and offering patient benefits, very good news.
No doubt about it, Spectranetics (Colorado Springs, Colorado) was celebrating yesterday with its report that, with FDA approval, it was given the go-ahead to stop its CELLO trial after completing about three-quarters of enrollment.
"The FDA agreed that the preliminary data was strong enough to meet the endpoints," Don Markley, a spokesperson for Spectranetics, told Medical Device Daily.
CELLO (pronounced like the instrument) is designed to explore use of the company's TURBO-Booster product in clearing blockages in the superficial femoral artery (SFA), and the company had enrolled 61 of the planned total of 81 patients.
The SFA is the main artery above the knee, and the company's TURBO-Booster is a laser/catheter system for removing blockages in that area that can result in severe complications, including amputation of the leg.
The primary endpoint of CELLO included angiographic core lab measurements of the percent reduction in diameter stenosis following treatment with the company's laser. Other clinical endpoints included 30-day patency using core lab-evaluated duplex ultrasound, improvements in ankle-brachial index and improvement in the ability to walk, 30 days post-procedure.
Thus far, the company has focused on using its technology in blockages below the knee, and the above-the knee application provides a much larger opportunity, since it believes that two-thirds of an estimated 400,000 endovascular procedures in the U.S. are performed to treat blockages above the knee.
"This is potentially a transforming event for us, providing the FDA clears the product," Guy Childs, CFO for Spectranetics, told Medical Device Daily.
Being obviously cautious, Childs characterized the data in the trial, to date, as "preliminary." While he said that both the company and the FDA could characterize the data as "encouraging," he added: "I would qualify that by saying we still have to gather it all and do all the analysis."
The trial was single-arm, he said, because there is really no comparison allowing establishment of a control arm in terms of balloon or stent use, especially for treating lesions up to 15 cm, as seen in CELLO.
"Balloons have been shown to be ineffective," Childs said. "They're used, but the durability of the results is not that good." Stents used for this type of treatment he characterized as having "a high fracture rate."
The company said that the follow-up data for CELLO is expected to be gathered early in 2Q07 and an 510(k) application filed with the FDA later in the quarter.
The TURBO-Booster is a deflecting sheath that is used with Spectranetics' existing TURBO elite laser catheters.
This laser technology is a percutaneous, less-invasive treatment for delivering what it describes as "relatively cool ultraviolet energy to ablate or remove arterial blockages including plaque, calcium and thrombus." The energy is delivered in pulses via a wavelength of 308 nanometers, vaporizing the clot materials into particles. The UV energy is transmitted along flexible glass fibers encased in catheters, which can be passed through arteries and veins in a procedure the company calls "safer and simpler" than other procedures.
The company launched CELLO in July of 2006, the first patient treated being an 72-year-old woman suffering from severe, "lifestyle-limiting claudication" (Medical Device Daily, July 22, 2006.) In that case, the system was used to treat an artery 85% blocked in an artery 6 mm in diameter.
At the time, the company said that the stenosis was reduced by 25% and required no follow-on adjunctive treatment with other devices.
John Schulte, president/CEO of Spectranetics, said in a statement, "Completion of the CELLO trial has been our top priority since the trial began nine months ago, and we are pleased that we have concluded enrollment in the trial ahead of our own expectations.
"We look forward to the opportunity to participate in this large and growing market segment. We will now turn our attention to efficiently gathering and analyzing all of the clinical data from the CELLO trial for our pending submission to the FDA."
Spectranetics broadened focus to clearance of blockages in the upper legs will put it competitively in a sector currently being developed by Fox Hollow Technologies (Redwood City, California), with its SilverHawk atherectomy device.
Rather than using laser energy, the SilverHawk system uses a small rotating blade to shave away plaque from inside the artery. As it is excised, the plaque collects in the tip of the device and then is removed from the patient.
Spectranetics calls its CVX-300 excimer laser the only system approved in the U.S., Europe, Japan and Canada for use in multiple, minimally invasive cardiovascular procedures, including atherectomy — a procedure to remove arterial blockages in the peripheral or coronary vasculature — and the removal of infected, defective or abandoned cardiac lead wires from patients with pacemakers or implantable cardiac defibrillators.
The company reports more than 600 laser ablation systems installed worldwide, about 500 of these in the U.S.
Spectranetics was founded in 1984 by Robert Golobic, PhD, a physicist with the U.S. Air Force physicist, and Johan Sverdrup, an engineer who worked for Hewlett-Packard. Golobic had been working on lasers as part of the Strategic Defense initiative and Sverdrup had done ultrasound work with ADR (Advanced Diagnostic Research) and Doppler imaging with Vingmed. Together they created Spectranetics as one of the first companies to explore the possibility of using the ultraviolet laser for artery clearance. The first patient was treated at the Texas Heart Institute (Houston) in 1989.