A Retrospective Analysis of FDA Warning Letters Issued For Biologics From 2010 To 2025

To lawfully market any drug products, biosimilars, or vaccines in the United States, the Food and Drug Administration (FDA) must provide a valid license or approval. The FDA takes full responsibility for protecting public health by regulating food and drug substances for their purity, safety, and efficacy. Biologics or biopharmaceuticals represent a rapidly growing field due to recent technological advancements and their targeted therapy advantages. To maintain the quality and safety of approved drugs, the FDA conducts periodic inspections.

This study aims to analyze the causes and trends of warning letters issued to biologics for current good manufacturing practices (CGMP) and Data integrity violations during 2010–2025, and provide preventive measures to impart knowledge to drug developers, thereby avoiding warning letters.

The warning letters issued from 2010 to 2025 were pulled from the FDA Compliance and Inspection Dashboard on the FDA website. Complete details on the manufacturer, country, nature of the violation, and other related details were obtained from the warning letter and thoroughly analyzed, summarized, tabulated, and concluded on the most common violations.

The study reveals that most violations are related to CGMP issues, including compromised data integrity and misbranding. In-depth analysis of CGMP warning letters in the study revealed three major repeated violations, namely, written procedure deviations, stability testing, and gaps in production record review by QC, corresponding to 17%, 15%, and 14%, respectively.

Review of warning letter analysis depicts that the FDA’s major enforcement actions are on CGMP Violations. Manufacturers should understand the importance and develop an internal checklist to follow the same, improve documentation practices with the latest technology, and conduct regular applicable training, to avoid any possible actions. The globalisation and advancements in technology should be used wisely to plan an upgraded quality management system on par with current guidelines.