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U.S. Department of Health and Human Services

Post-Approval Studies (PAS) Database

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The FDA has the authority to require sponsors to perform a post-approval study (or studies) at the time of approval of a premarket approval (PMA), humanitarian device exemption (HDE), or product development protocol (PDP) application. Post-approval studies can provide patients, health care professionals, the device industry, the FDA and other stakeholders information on the continued safety and effectiveness (or continued probable benefit, in the case of an HDE) of approved medical devices. This database allows you to search Post-Approval Study information by applicant or device information.

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Study Status Completed
Application Number P140004 / PAS001
Date Current Protocol Accepted  
Study Name SPACER
General Study Protocol Parameters
Study Design Randomized Clinical Trial
Data Source New Data Collection
Comparison Group Concurrent Control
Analysis Type Analytical
Study Population Adult: >21
Detailed Study Protocol Parameters
Study Design Description To demonstrate that the success rate of the study group receiving the Superion Interspinous Spacer (investigational arm) is not inferior to the success rate observed in X-STOP IPD control group when the device is used in patients with moderately impaired degenerative lumbar stenosis at 5 years post-surgery.
Study Population Description Subjects suffering from moderate symptoms of neurogenic claudication secondary to a confirmed diagnosis of moderate LSS at one or two contiguous levels from L1 to L5 who meet all inclusion/exclusion criteria. Study subjects were randomized to treatment with either the Superion ISS or X-STOP IPD interspinous devices.
Sample Size The numbers of patients in the final primary analysis set for effectiveness and safety included 190 patients randomized to Superion® and 201 patients randomized to the X-STOP® IPD® Control group. Eight (8) Superion® patients and 12 X-STOP® IPD patients are from 2 sites that are not participating in the PAS. This reduces the analysis set to 182 and 189, respectively.
Data Collection An individual will be considered a success if they meet all of the following conditions at the 60-month follow-up visit:

Clinically significant improvement as compared to baseline as determined by meeting at least two of the three domains of ZCQ (as defined in the protocol); no re-operations, revisions, removals or supplemental fixation at the index level(s); no major implant or procedure-related complications; and no clinically significant confounding treatments.

Data will be evaluated for safety endpoints by an independent Clinical Events Committee (CEC). Safety outcomes will be determined by evaluating the type, frequency, severity, and relationship to device of adverse events through the 60-month time point for all subjects. Adverse events will be categorized as implant-related or procedure-related. All device-related and major procedure-related failures reported by the site PIs will be adjudicated by the independent CEC. In addition, events reported as having unknown or undetermined relationship to the device by the PI will be adjudicated by the CEC.

Follow-up Visits and Length of Follow-up length of follow-up: 60 months

frequency of follow-up: yearly
Interim or Final Data Summary
Actual Number of Patients Enrolled 28 non-randomized training patients and 391 randomized patients (190 in Superion/treatment arm, 201 in X-STOP/control).
Actual Number of Sites Enrolled 31
Patient Follow-up Rate At 60 months, 85.8% for Superion IDS and 82.1% for X-STOP IPD
Final Safety Findings The incidence of any adverse event, device-related adverse events, procedure-related adverse events, serious adverse events, and device- or procedure-related serious adverse events were similar between both groups at 60 months.
Final Effect Findings The primary effectiveness endpoint was a composite endpoint comprised of four elements:

1. Clinically significant improvement in outcomes compared to baseline, as determined by meeting the following for at least two of three domains of the Zurich Claudication Questionnaire (ZCQ):

2. No re-operations, revisions, removals, or supplemental fixation at the index level(s)

3. No major implant or procedure-related complications

4. No clinically significant confounding treatments.

The overall Composite Clinical Success demonstrates that the Superion is non-inferior to the X-STOP at all yearly time points through the 60-month follow-up.
Study Strengths & Weaknesses Study strengths include comprehensive endpoints, a clinical control, and inclusion of a “patient preference” evaluation. The most notable study weakness is that it lacks a comparison to conservative (non-operative) treatment.
Recommendations for Labeling Changes At the close of the report, we recommended that the sponsor update the labeling with the 60 month data. We are currently reviewing this data.

SPACER Schedule

Report Schedule
Date Due
FDA Receipt
Applicant's Reporting Status
one year report 05/19/2016 05/20/2016 Overdue/Received
Final Report 02/17/2017 02/21/2017 Overdue/Received

Contact Us

Mandated Studies Program
Food and Drug Administration
10903 New Hampshire Ave.
Silver Spring, MD 20993-0002
Email: MandatedStudiesPrograms@fda.hhs.gov

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