• Decrease font size
  • Return font size to normal
  • Increase font size
U.S. Department of Health and Human Services

Post-Approval Studies (PAS)

  • Print
  • Share
  • E-mail

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.

Learn more...


Concentration and Molecular Weight

Suggest Enhancement / Report Issue | export reports to excelExport to Excel
Study Status Completed
Application Number P090016 / PAS002
Date Current Protocol Accepted 03/08/2013
Study Name Concentration and Molecular Weight
General Study Protocol Parameters
Study Design Bench/Lab Study
Data Source New Data Collection
Comparison Group No Control
Analysis Type Descriptive
Detailed Study Protocol Parameters
Study Design Description Bench/Lab study to evaluate the concentration and molecular weight distribution of low molecular weight hyaluronic acid fragments in Belotero Balance as a function of time.
Study Population Description Not applicable. This is a bench/lab study.
Sample Size Not applicable. This is a bench/lab study.
Data Collection Not applicable. This is a bench/lab study.
Follow-up Visits and Length of Follow-up Not applicable. This is a bench/lab study.
Interim or Final Data Summary
Actual Number of Patients Enrolled n/a - bench study
Actual Number of Sites Enrolled n/a - bench study
Patient Follow-up Rate The concentration and molecular weight distribution of low MW hyaluronic acid (HA) fragments in three Belotero Balance batches are determined in a laboratory study as a function of time during 18 months.
Final Safety Findings ¿The study results fulfilled the second condition of approval: the sponsor should provide ¿results of studies to evaluate the concentration and molecular weight (MW) distribution of low MW hyaluronic acid (HA) fragments in Belotero Balance as a function of time.¿ HA is a listed ingredient and not a proprietary ingredient. This study reports in each additional time point, during 18 months, additional information about the nature of the soluble fraction HA degradation.

¿Changes in soluble HA fraction are due to degradation of soluble HA within the device, as well as conversion of crosslinked HA to soluble HA. Both effects are linked to hydrolysis of the HA molecule. The mechanism for these increased degradation periods remains unclear.

¿As HA degrades, the % and average MW of the soluble HA fraction increases. However, this increase appears to be temporary as degradation of newly soluble HA occurs. Polydispersity is also lowered as high MW HA fragments degrade over time.

¿Because only soluble HA was evaluated (and not the crosslinked portion), and because the nature of the soluble HA was variable from time point to time point, it is difficult to draw correlations between the viscosity of the material and the network structure/MW distribution of the product. Generally speaking, physical properties arise from chemical characteristics. In this case, there are multiple factors, chiefly the distribution and degradation of the soluble HA component (and secondarily the apparent burst release of soluble HA), that may ultimately lead to the decrease in material properties.

Study Strengths & Weaknesses A. Strengths:

¿The evaluation methods used in this study effectively evaluated the concentration and distribution of the MW of HA, and revealed certain empirical information regarding the behavior and properties of this device as it age, particularly the potential for stepwise changes in chemical and mechanical properties.

¿The methodology used in this study could be helpful in the evaluation of this class of devices (HA filler products) and may provide the opportunity to compare results with each other.

B. Weaknesses:

¿The methodology used was limited in scope to evaluate soluble HA.

Recommendations for Labeling Changes No labeling changes are recommended because no unexpected findings were reported and no additional information from the PAS is needed in the labeling.

Concentration and Molecular Weight Schedule

Report Schedule
Date Due
FDA Receipt
Applicant's Reporting Status
interim report (six month) 05/14/2012 05/25/2012 Overdue/Received
one year report 11/13/2012 11/09/2012 On Time
18 month report 05/14/2013 05/14/2013 On Time
two year report 11/13/2013 11/07/2013 On Time
three year report-final report 11/13/2014 11/12/2014 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

Related Links