FDA Announces International Progress in Replacing Horseshoe Crab Testing

WASHINGTON, D.C.—The Physicians Committee for Responsible Medicine applauds the U.S. Food and Drug Administration and its international regulatory partners for advancing an approach that could reduce reliance on horseshoe crab blood in medical product safety testing while protecting human health.

The FDA announced that it had successfully completed an international collaborative assessment of a protocol that companies can use when making manufacturing changes after a medicine has already been approved. The change evaluated in this case involved replacing the traditional Limulus Amebocyte Lysate (LAL) test, which relies on horseshoe crab blood, with a synthetic animal-free test for harmful bacterial contaminants known as endotoxins. The assessment marks an important step toward broader global acceptance of methods that can replace the use of horseshoe crabs.

“Regulatory collaboration can be a powerful catalyst for getting better testing methods into use,” said Janine McCarthy, MPH, director of research policy at the Physicians Committee. “When agencies align their scientific expertise and regulatory expectations, it becomes easier for companies to move away from animal-based methods and toward technologies that are more sustainable, reliable, and relevant to human health.”

Endotoxin testing is an essential quality-control measure for medical products because these harmful substances can cause serious adverse reactions in patients. Synthetic methods offer an alternative to the traditional LAL test without requiring the collection and bleeding of horseshoe crabs. These methods can provide reliable safety testing while supporting the FDA’s broader efforts to modernize pharmaceutical testing and reduce and replace animal use.

The FDA conducted the assessment with regulatory authorities from Australia, Canada, Japan, Switzerland, and the European Union. The collaborative assessment, conducted through the International Coalition of Medicines Regulatory Authorities (ICMRA), resulted in approval of a Post-Approval Change Management Protocol in June 2026. For the first time, several regulators reached almost simultaneous and aligned decisions to approve this type of manufacturing change after reviewing it independently, demonstrating the reliability of the synthetic test method.

The FDA’s involvement in this collaboration signals support for companies to transition their existing product registrations toward nonanimal endotoxin tests and offers a regulatory protocol for them to do so. This announcement demonstrates how regulatory agencies can facilitate a globally coordinated shift away from animal-based approaches and toward more modern nonanimal methods through international coalitions.

The Physicians Committee encourages the FDA to build on this progress by expanding the acceptance and implementation of synthetic endotoxin test methods and other nonanimal approaches across pharmaceutical development and regulatory decision-making, including through guidance updates.

To speak with Ms. McCarthy, please contact Reina Pohl at 202-527-7326 or rpohl [at] pcrm.org.