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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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Paragon PAS

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Study Status Completed
Application Number P050031 / PAS001
Date Current Protocol Accepted 06/06/2007
Study Name Paragon PAS
General Study Protocol Parameters
Study Design Active Surveillance
Data Source New Data Collection
Comparison Group Objective Performance Criterion
Analysis Type Analytical
Study Population Child: 2-12 yrs, Adolescent: 13-18 yrs, Transit. Adolescent B (as adults) : 18-21 yrs, Adult: >21
Detailed Study Protocol Parameters
Study Design Description The study is a retrospective study design where a randomly selected, stratified sample of 200 practitioners will be identified to determine their patients fit with duration of lens wear, and establish the presence or absence of a history of microbial keratitis. For practitioners who ordered less than 25 pairs of the lenses in 2004 and 2005, all patients will contribute to the analysis and those who ordered 25 or more, no more than 50 patients will contribute to the analysis. This post-approval study condition of approval is being fulfilled by a 522 study that was already proposed when this device was approved.
Study Population Description Study population is as per approved device indication: The lenses are indicated for use in the reduction of myopic refractive error in non-diseased eyes. The lenses are indicated for overnight wear in a Contact Lens Corneal Refractive Therapy fitting program for the temporary reduction of myopia up to 6.00 diopters in eyes with astigmatism up to 1.75 diopters. The lenses may be disinfected using only a chemical disinfection system. Practitioners were surveyed and asked if they had observed microbial keratitis cases among the patients who received the device.
Sample Size Approximately 1,000 pediatrics and 1,000 Adults. A total of 2,000 patient-years had to be accrued
Data Collection Cases of microbial keratitis (MK)
Follow-up Visits and Length of Follow-up On average each subject was to be followed for 1 year
Interim or Final Data Summary
Interim Safety Information Final Report submitted, currently under FDA review.
Actual Number of Patients Enrolled 1317
Actual Number of Sites Enrolled 86
Patient Follow-up Rate 84.8%
Final Safety Findings Incidence of microbial keratitis was the main study endpoint.

A total of 2,599 patient-years of lens wear for 1,317 patients were included in the analysis. At the original fitting date the mean age of the pediatric group was 12.2_+ 2.5 years and for adults was 38.0 + 11.1 years. The mean follow-up for the pediatric group was 2.1+0.8 years, with 620 (92%) having at least 12 months of follow-up, for adults the mean follow-up was 1.8+10 years, with 497 (78%) having at least 12 months of follow-up.

The outcome Assessment Panel identified two cases of microbial keratitis within 2,599 patient years of overnight corneal reshaping lens wear. Both cases of microbial keratitis occurred at least one year after fitting and neither resulted in any documented long-term loss of best corrected visual acuity. The overall estimated incidence of microbial keratitis is 0.00077 per patient-year including the estimated incidence of 0.00139 per patient-year for the pediatric group, and 0.0 per patient-year for adults. The two-sided 95% confidence interval for difference in risk between the two age groups was -0.00139 to 0.00509.

A conservative analysis of 685 patients who began wear of overnight corneal reshaping lenses after January 2005 and had at least one year of document lens wear shows a total of 1,415 patient-years of lens wear (794 pediatric and 621 adult). The two-sided 95% confidence interval for difference in risk between the two age groups was -0.00341 to 0.00927.
Final Effect Findings Not applicable
Study Strengths & Weaknesses Due to the nature of retrospective study design, the study was conducted in relatively short period of time, achieving the required number of patient years, as per protocol. However, there are certain study limitations: loss of follow-up of patients with the event of interest, who could seek medical care elsewhere, may introduce bias that could result in no difference between the comparison groups. Additionally, there was low participation rate among the practitioners who were asked to participate in the study, only 86 out of 200 participated.
Recommendations for Labeling Changes Yes.

The recommended labeling change includes a summary of the 522 study including: introduction, study objective, study design, results, conclusions and strengths and limitations.

Paragon PAS Schedule

Report Schedule
Date Due
FDA Receipt
Applicant's Reporting Status
Status Report 09/05/2008 09/05/2008 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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