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# FDA Warns 2 Breast Implant Makers on Studies
- URL: https://www.fdaweb.com/fda-warns-2-breast-implant-makers-on-studies/
- Published: 2019-03-19T12:00:00.000Z
- Updated: 2026-09-15T01:14:02.000Z
- Author: David McFarland
- Tags: Devices, #legacy-id-D5143648

FDA has issued Warning Letters to two breast implant manufacturers for failing to comply with post-market study requirements included in their premarket approval orders. The studies were to assess the long-term safety and risks of the companies’ silicone gel-filled implants. Warning Letters went to Mentor Worldwide, Irvine, CA, and Sientra, Santa Barbara, CA.

The Mentor [letter](https://www.fda.gov/ICECI/EnforcementActions/WarningLetters/ucm633710.htm?ref=fdaweb.com) noted several serious deficiencies, including that the company failed to enroll the required number of patients in the study, had poor follow-up rates with study patients, and had significant data inconsistencies, including poor patient accounting and missing race and ethnicity data.

The Sientra [letter](https://www.fda.gov/ICECI/EnforcementActions/WarningLetters/ucm633719.htm?ref=fdaweb.com) said the manufacturer had a follow-up rate of 61%, below the target rate.

Both companies were told to respond with details on how they will correct the violations.