Dexcom has received a warning letter from the U.S. Food and Drug Administration (FDA) after inspections at its manufacturing facilities in San Diego, CA, and Mesa, AZ. The letter, issued on March 4, highlights deficiencies in the company’s responses to earlier inspection findings, known as a Form 483.

The FDA identified issues in Dexcom’s manufacturing processes and quality management system. While the warning letter does not restrict Dexcom’s ability to produce or sell its continuous glucose monitors (CGMs), the company must address the concerns to avoid further regulatory action. Dexcom has already submitted multiple responses to the FDA and is preparing a formal reply to the warning letter.

Despite the warning, the company does not expect a significant impact on its manufacturing capacity or financial guidance for 2025. However, it has not provided a timeline for resolving the matter, and the FDA could take additional action if the concerns are not adequately addressed.

What is an FDA Form 483?

An FDA Form 483 is a document given to a company after an FDA inspection. It lists problems or concerns that inspectors find at facilities that make food, drugs, or medical devices.

Here’s what it means:

• It’s not a penalty or legal action but a notice that improvements are needed.
• Inspectors discuss the issues with company management at the end of the inspection.
• Companies usually have 15 days to respond with a plan to fix the problems.
• Issues can range from minor concerns to more serious problems that could affect product safety or quality.

Think of a Form 483 as a report card from the FDA. It points out areas where a company needs to improve to meet safety and quality standards. If the FDA is not satisfied with a company’s response, it may escalate the situation with a warning letter, as happened in Dexcom’s case. However, unless more serious action is taken, such letters often signal a need for clarification rather than a major compliance failure.

For more information, please visit Drug Delivery Business.

Update – March 28, 2025

The full FDA warning letter issued to Dexcom is now publicly available. It cites unauthorized manufacturing changes to both G6 and G7 continuous glucose monitoring sensors, including modifications to the resistance layer coating that were not disclosed to the agency. According to the FDA, clinical testing showed increased variability in sensor accuracy with the modified component. While Dexcom has stopped distribution of G7 sensors containing the change, the company has not addressed the status of G6 sensors already in commercial use​.

Dexcom has pushed back on the FDA's findings, stating the changes did not affect device safety or performance and did not warrant premarket notification. The company says many of the cited issues have already been resolved and that it continues to cooperate with the FDA​.

For more information, please visit:

FDA Warning Letter to Dexcom, Inc. (March 4, 2025): FDA.gov
Dexcom’s FDA warning letter reveals unauthorized changes to sensors: MedTech Dive
Dexcom rejects claims of unauthorized device changes in FDA warning letter: MedTech Dive