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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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Single Tined Lead (protocol 1634)

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Study Status Completed
Application Number P970004 S022/ PAS003
Date Current Protocol Accepted 04/02/2010
Study Name Single Tined Lead (protocol 1634)
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 Prospective, multicenter Phase I -randomized trial Phase II- non-randomized
Study Population Description Phase I: Subjects enrolled and randomized either to InterStim Therapy (without OAB medications) or to Standard Medical Therapy and followed for # months. At month #, subjects in the Standard Medical Therapy group may undergo test stimulation and if successful receive the InterStim device.

Phase II: A sufficient number of additional subjects will be enrolled and not randomized. They will undergo test stimulation and if successful will receive the InterStim device in order to meet long-term follow-up sample size requirement.

Sample Size Phase I: # (#) will be randomized.

Phase II: # subjects receiving full implant for # year endpoint

Data Collection Efficacy: At least # improvement in average voids/day from baseline or a return to normal voiding frequency (#) for subjects with urinary frequency at baseline. At lease # improvement in average leaks/day from baseline for subjects with urinary incontinence at baseline.

Subjects with both frequency and incontinence at baseline must meet at least one of the above criteria to be considered a success.

Safety: Demonstrate that the upper bound of the #CI for the cumulative five-year rate of adverse events related to tined lead that require surgery after a full system implant is less than #.

Follow-up Visits and Length of Follow-up 5 years

After full-system implant, follow-up visits will be completed for subjects at months 3, 6, 12, 24, 36, 48, and 60 months. For subjects randomized to InterStim who fail test stimulation will be followed for # months.

Subjects in Phase II who fail test stimulation will be exited from the study.

Interim or Final Data Summary
Actual Number of Patients Enrolled 571 subjects were enrolled in the study, 272 subjects were implanted with the full system, and 169 had 5year data.
Actual Number of Sites Enrolled 38 sites
Patient Follow-up Rate 62% (169/272)
Final Safety Findings The primary safety objective was to demonstrate that the upper bound of the 95% confidence interval for the cumulative 5-year rate of adverse events related to the tined lead requiring surgery was less than 33%. In the InSite study, the 5-year cumulative event rate was 22.4% (95% CI: 16.6%-27.7%). With an upper 95% CI limit of 27.7%, the study primary safety endpoint was met.
Final Effect Findings The primary effectiveness analysis demonstrated that, at 5 years post-implant, 67% of subjects were OAB responders (meaning reduced symptoms of urinary urge incontinence). In addition, 64%, and 57% of subjects were urge incontinence (UI) responders and urgency-frequency (UF) responders, respectively, at 5 years. Sensitivity analyses demonstrated similar results, indicating that the main study findings regarding the treatment effect of InterStim is impacted substantially by missing data.

Study Strengths & Weaknesses Strengths of this study include a multi-center, prospective design of adequate sample size for long-term (5-year) evaluation of the safety and effectiveness endpoints. The main weakness of the study is the limited generalizability of the long-term results. Given the attrition rate of 26.9% at 5 years, the main study findings may be an over-estimate of true device performance by potentially excluding patients who were poor responders to InterStim treatment.
Recommendations for Labeling Changes Labeling changes are recommended based on the long-term (5-years) safety and effectiveness results of the PAS.

Single Tined Lead (protocol 1634) Schedule

Report Schedule
Date Due
FDA Receipt
Applicant's Reporting Status
6 month report 10/23/2010 09/30/2010 On Time
1 year report 04/02/2011 04/04/2011 On Time
18 month report 10/02/2011 09/30/2011 On Time
2 year report 04/02/2012 03/30/2012 On Time
3 year report 04/02/2013 04/01/2013 On Time
4 year report-Phase I 04/02/2014 04/03/2014 Overdue/Received
5 year report 04/02/2015 04/01/2015 On Time
6 year report 04/02/2016 04/01/2016 On Time
amended 6 year report 05/13/2016 05/13/2016 On Time
Final Report 10/31/2016 10/31/2016 On Time

Contact Us

Julie Unger
Project Manager, Post-Approval Studies Program
Food and Drug Administration
10903 New Hampshire Ave
WO66-4206v Silver Spring, MD

Phone: (301) 796-6134
Fax: (301) 847-8140

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