Warning Letter

A Warning Letter is a formal correspondence from the U.S. Food and Drug Administration (FDA) to a manufacturer, distributor, or other responsible party notifying them of significant violations of the Federal Food, Drug, and Cosmetic Act (FD&C Act) or FDA regulations. It represents one of the most serious regulatory enforcement tools short of legal action.

What triggers a Warning Letter:
Warning Letters are typically issued following:
- FDA inspection with serious Form 483 observations
- Failure to adequately respond to Form 483
- Repeated or serious violations of Good Manufacturing Practices (GMP)
- Marketing unapproved devices
- Misbranding or adulteration of devices
- Failure to submit required reports (MDRs, 510(k))
- False or misleading advertising

Common violations for medical devices:
- Quality System/GMP violations - Inadequate design controls, CAPA system failures, validation deficiencies
- Premarket violations - Marketing devices without required 510(k) clearance or PMA approval
- Labeling violations - False or misleading claims, inadequate warnings
- Registration violations - Failure to register establishment or list devices
- Post-market violations - Failure to report adverse events, recalls conducted improperly
- Clinical trial violations - Conducting studies without IDE approval, informed consent issues

Response requirements:
Companies must respond within 15 business days describing:
- Specific corrective actions taken or planned
- Timeline for implementation
- How the company will prevent recurrence
- Documentation supporting the corrections

Consequences of non-compliance:
Failure to adequately address Warning Letter violations can result in:
- Import detention or refusal
- Product seizure
- Injunction against manufacturing or distribution
- Consent decree with court oversight
- Civil monetary penalties
- Criminal prosecution in severe cases
- Exclusion from federal healthcare programs

Public disclosure:
All Warning Letters are publicly posted on the FDA website, potentially damaging company reputation and affecting stock prices for public companies.

Resolution process:
The FDA closes Warning Letters when satisfied with corrective actions, typically after:
- Review of written response
- Follow-up inspection confirming implementation
- Demonstration of sustained compliance

Warning Letter vs. Untitled Letter:
- Warning Letter - Serious violations that may lead to enforcement action
- Untitled Letter - Less serious violations, but still requiring correction

Companies should treat Warning Letters with utmost seriousness, often engaging regulatory consultants and legal counsel to ensure comprehensive responses.