This article is more than 5 years old. Information may no longer be current.
Panel recommends FDA approve VertiFlex spinous spacer by 5-1 vote, 2 abstentions
The Orthopaedic and Rehabilitation Devices Panel of the FDA voted in favor of three questions posed to them when they met on February 20 about the safety, efficacy and benefits vs. perceived risks of an interspinous spacer device to treat moderate lumbar spinal stenosis.
The sponsor, VertiFlex Inc., San Clemente, Calif., manufactures the Superion InterSpinous Spacer (ISS), and presented its premarket approval application (PMA) (P140004).
Eight voting members of the panel, which included spine surgeons and orthopedic surgeons, were presented with three questions and for the first two questions they voted 5 to 1, with two abstentions, which meant they felt there was reasonable assurance the sponsor’s device was safe to treat moderate lumbar spinal stenosis (LSS) and was effective in patients who met the criteria in the proposed indications.
The proposed indications were for skeletally mature patients with pain, numbness, and/or leg cramping (neurogenic intermittent claudication) secondary to a diagnosis of moderate LSS, with or without Grade 1 spondylolisthesis.
Spinous process fractures were focused on in the FDA’s questions. When asked if the probable benefits of the sponsor’s device outweighed the probable risks, four panel members voted yes, two voted no and two abstained.
Raj D. Rao, MD, chair of the FDA panel and a Spine Surgery Today Editorial Board member, told Spine Surgery Today after the meeting the panel generally supported the VertiFlex PMA.
“Having said that, there were some general concerns with the comparator group, and how the comparator group X-STOP had less than optimal results for our patients,” he said.
Presentations focused on results of the Superion investigational device exemption trial, which enrolled 470 adults with moderate spinal stenosis treated who were randomized 1:1 to receive the Superion ISS or the X-STOP (Medtronic; Langhorne, Pa.) device used as control treatment, which has similar indications.
Success was defined as clinically significant improvement in outcomes compared to baseline for at least two of three Zurich Claudication Questionnaire domains and no clinically significant confounding treatments.
At 24-months follow-up, 52.7% of the Superion ISS group and 50.2% of the X-STOP group were considered successful. Study data showed spinous process fractures developed after treatment in 16.3% of Intent-to-Treat (mITT) subjects in the Superion ISS group and 8.5% of control mITT subjects. Some fractures in both groups exhibited healing at various times during follow-up.
At the meeting, Stephen Lyman, PhD, temporary voting member of the panel, said, “As we heard earlier, and we did not have verification from the FDA or anyone else, the panel originally did not want to approve X-STOP but did anyway….In my mind, if you are taking something that was a controversial device from the beginning and using that as a comparison group, you are setting a very low bar clinically. On top of that, you are only looking at noninferiority. You are not looking at improvement.”
If the device is deemed approvable by the FDA, Vertiflex proposed two studies with 5 years follow-up to compare the outcomes of patients with the interspinous device to those who underwent decompression. – by Robert Linnehan