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U.S. Department of Health and Human Services

Post-Approval Studies (PAS)

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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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Durability PAS

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Study Status Completed
Application Number P110023 / PAS001
Date Current Protocol Accepted 11/23/2016
Study Name Durability PAS
General Study Protocol Parameters
Study Design Prospective Cohort Study
Data Source Sponsor Registry
Comparison Group Objective Performance Criterion
Analysis Type Analytical
Detailed Study Protocol Parameters
Study Design Description The PAS is a prospective, multi‐center, non‐randomized, single arm study with sequential enrollment of all qualified subjects undergoing treatment of atherosclerotic lesions in the native superficial femoral artery or the superficial femoral and proximal popliteal arteries. All eligible subjects who provide informed consent will undergo PTA and stenting using the EverFlex device. Follow‐up will take place at pre‐ discharge, 30 days, 1 year, 2 years and 3 years.
Study Population Description Adult patients with lesions no greater than 180 mm in length in the native superficial femoral artery or the superficial femoral and proximal popliteal arteries, who do not meet any of the exclusion criteria for this device.
Sample Size The sample size of 108 is driven by the need for the above noted precision confidence interval for stent fracture rate. This sample size will ensure precision of the stent fracture rate at 1 year with a 95% confidence interval upper bound of 6.6%, assuming a proportion of 1 year fracture rate of 3.0%, and a 10% attrition at 1 year. Also, assuming that the true 36 month composite primary endpoint rate is 55% (with a performance goal of greater than 35%) and 30% attrition at 36 months, the resulting 108 evaluable subjects are greater than the 89 required to power the primary endpoint.

Twenty (20) to 30 sites will be used in the study.

Data Collection Primary endpoints

A composite endpoint defined as freedom from acute death, freedom from 36‐month amputation, and freedom from 36‐month clinically‐

driven target lesion revascularization

Secondary endpoints

 Freedom from stent fracture at 1, 2, and 3 years

 Freedom from 36‐month amputation at 1, 2, and 3 years

 Freedom from 36‐month clinically driven target lesion revascularization at 1, 2, and 3 yrs

 Freedom from acute death (within 30 days of the procedure)

 Device success ¿ ability to employ the device as intended

 Improvement in Rutherford clinical category at one year

 Improvement in ankle‐brachial index at one year

 Walking improvement at one year

 Adverse events, including all cause mortality

Follow-up Visits and Length of Follow-up Follow‐up visits will occur pre‐discharge, at one month, at one year, and annually thereafter, up to three years.
Interim or Final Data Summary
Actual Number of Patients Enrolled One hundred and eight (108) subjects were enrolled in the study.
Actual Number of Sites Enrolled Twenty-three (23) sites were enrolled in the United States.
Patient Follow-up Rate Follow-up rate at 1 year was 90.7% (98/108), at 2 years was 83.3% (90/108), and at 3 years was 76.9% (83/108).
Final Safety Findings The primary safety endpoint is a composite endpoint of freedom from acute death (death

within 30 days post procedure), freedom from 36- month amputation, and freedom from 36-

month clinically driven target lesion revascularization (CD-TLR).

The 36-month freedom from the primary safety composite event was 77.1% with 97.5% lower

confidence bound of 67.8%, that is greater than the prespecified performance goal of 35%

(p<0.001). Therefore, the study met the primary safety composite endpoint.
Final Effect Findings Freedom from Stent Fracture at 1-year (365 days) was 100%, 98.9% at 2 years (730 days) and

96.5% at 3-years (1095 days) post procedure.

Freedom from acute death, freedom from amputation and freedom from CD-TLR rate at 1-year

post procedure was 86.0%, and at 2 years post procedure was 78.2%.

Freedom from Amputation was 100% at 1 year and 99.0% at 2- and 3 years post-procedure.

Freedom from Clinically Driven TLR was 86.0% at 1-year post-procedure, 79.2% at 2

year post procedure and 78.1% at 3 years post-procedure.

Acute death rate at 30 days was 0%.

Freedom from all-cause mortality rate at 1 year was 100%, at 2 years was 97.1%, and at 3 years

was 91.6%.

There were 118 stents implanted in 108 enrolled subjects. Device success rate was 100%


Improvement in Rutherford Clinical Category at 1 year compared to baseline was observed in

92.6% (88/95) of the Subjects.

The mean Ankle-Brachial Index (ABI) at 1- year post-procedure improved by 0.26 (+/- 0.20) compared to baseline. The proportion of subjects with improvement was 87.3% (62/71).
Study Strengths & Weaknesses Strength: The study met its primary safety composite endpoint compared to the pre-specified performance goal, (lower bound 67.8% vs 35% PG, p<0.001). Follow-up was achieved in approximately 80% of subjects at 3 years. Study was conducted on US subjects only.


This was a single- arm observational study and therefore did not have the inherent advantages of a randomized control trial.
Recommendations for Labeling Changes Labeling change is recommended to reflect the long-term results of the post-approval study.

The labeling change should include a new section on the label showing a summary of the post-

approval study methods (including study objectives, design, population, number of enrolled

sites/subjects, key endpoints, follow-up visits etc.), final results, strengths and limitations of the


Durability PAS Schedule

Report Schedule
Date Due
FDA Receipt
Applicant's Reporting Status
six month report 09/05/2012 08/24/2012 On Time
one year report 03/07/2013 03/05/2013 On Time
18 month report 09/05/2013 09/04/2013 On Time
two year report 03/07/2014 03/04/2014 On Time
three year report 03/07/2015 02/27/2015 On Time
four year report 03/06/2016 03/02/2016 On Time
five year report 03/06/2017 03/03/2017 On Time
six year report 03/06/2018 03/05/2018 On Time
final report 03/06/2019 03/27/2019 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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