WHO Issues New Global Guidelines to Replace Animal Experiments for Medicinal Quality Control

Developed by the WHO Expert Committee on Biological Standardization (ECBS) and informed by an independent scientific assessment from the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), the guidelines provide international recommendations for quality control testing and reflect extensive input from stakeholders, including recommendations submitted by the Physicians Committee.

A major highlight is the WHO’s explicit recommendation to use nonanimal testing methods for pyrogenicity and endotoxin testing. Legacy animal-based methods, like the rabbit pyrogen test (RPT) and the horseshoe crab blood–derived Limulus Amebocyte Lysate (LAL) test, are not only cruel but also scientifically limited, and variable. In contrast, validated nonanimal methods, such as the monocyte activation test (MAT) to replace the RPT, and recombinant factor C (rFC) and recombinant cascade reagent (rCR) to replace the LAL test, offer more human-relevant, reproducible, and reliable approaches for ensuring product safety.

By harmonizing international recommendations, these WHO guidelines serve a critical function in quality control for global drug development, where manufacturers must navigate different regulatory requirements across countries. Notably, the WHO’s recommendations for the MAT and rFC/rCR tests were key takeaways from the Physicians Committee’s 2025 Cape May Event on animal-free endotoxin testing, which brought together pharmaceutical leaders to share their progress in replacing animal-based endotoxin tests and to discuss technical insights and strategies to smooth the transition.

A central concern raised by stakeholders is international divergence in endotoxin testing requirements. While Europe and the United States now accept rFC as a compendial or validated method, many countries have yet to update their guidelines. These new WHO recommendations offer a critical resource to help regulators worldwide adopt more ethical, reliable, and sustainable animal-free quality control methods.

Based on our discussions with industry and regulators, the Physicians Committee submitted comments to strengthen the 2025 WHO guidelines and contributed to the International Council on Animal Protection in Pharmaceutical Programmes (ICAPP) response. We are pleased that our recommendations were incorporated, specifically our request to prioritize rFC over LAL to reduce variability, and our recommendation that the guidelines explicitly endorse rFC or rCR for endotoxin testing without supporting LAL.

This is a meaningful win for animals and science. The Physicians Committee Responsible Medicine has been advocating for years to make these changes, and we are very excited to see progress from the World Health Organization. We look forward to the continued transformation of quality control testing methods toward a more predictive, reproducible, and fully animal-free future.