Par Health USA, LLC & Endo USA, Inc. – FDA Warning Letter, Oct 20, 2025

In a warning letter dated April 15, 2026, the FDA notified Par Health USA, LLC and Endo USA, Inc. of significant manufacturing violations at their Rochester, Michigan facility. Following an inspection conducted from October 6 to 20, 2025, the agency determined that the company’s sterile injectable drug products were manufactured in violation of Current Good Manufacturing Practice (CGMP) regulations, rendering them adulterated under the Federal Food, Drug, and Cosmetic Act.

The primary issues involved fundamental design flaws in aseptic processing lines. The FDA noted that equipment was misidentified as restricted access systems and required excessive manual interventions, which increased contamination risks. Furthermore, airflow studies failed to demonstrate adequate protection of sterile areas, and environmental monitoring was insufficient. Investigators also found that the company’s process simulations did not reflect worst-case production scenarios. Additionally, the facility’s visual inspection program was deemed ineffective, as it failed to consistently detect glass fragments and other particulates in finished drug products.

The FDA requires the company to hire independent consultants to perform a comprehensive risk assessment of their facility design, contamination hazards, and quality oversight systems. The firm must provide a detailed remediation plan that addresses equipment suitability, automated visual inspections, and staff training in aseptic techniques. A formal response outlining these corrective actions must be submitted within 15 working days. The agency warned that failure to resolve these deficiencies could result in legal action, such as product seizures or the withholding of new drug approvals.