Pyrogen detection is essential for ensuring the safety of parenteral medicines. For decades, the rabbit pyrogen test (RPT) has been the traditional method. The RPT involves measuring the rise in body temperature in rabbits following intravenous injection of the substance to be examined.

Despite multiple efforts to encourage medicine developers to move away from the RPT, the test is still widely used to detect pyrogenic substances, consuming a large number of rabbits worldwide.

At its 179th session in June 2024, as the outcome of a broad exercise aiming at the complete removal of the RPT from the European Pharmacopoeia (Ph. Eur.), the Ph. Eur. Commission adopted 57 revised texts from which the RPT has been deleted, together with a new general chapter on Pyrogenicity (5.1.13), marking the end of the RPT era in the Ph. Eur.  

As a result, the use of the RPT will no longer be required in any text of the Ph. Eur. and it will be the responsibility of medicine developers to select a suitable in vitro test (e.g. the monocyte-activation test) to control the pyrogenicity of their product, based on a risk assessment as described in the new general chapter.

The revised texts omitting the RPT and Pyrogenicity (5.1.13) will be published in Supplement 11.8 of the Ph. Eur., with an implementation date of 1 July 2025.

Read seminal ALTEX articles on the replacement of the pyrogen test:

Hartung, T., & Wendel, A. (1995). [Detection of pyrogens using human whole blood] [Article in German]. ALTEX 12, 70–75.

Schindler, S., von Aulock, S., Daneshian, M., & Hartung, T. (2009). Development, validation and applications of the monocyte activation test for pyrogens based on human whole blood. ALTEX 26, 265–277. doi:10.14573/altex.2009.4.265

Hartung, T. (2015). The human whole blood pyrogen test – lessons learned in twenty years. ALTEX 32, 79–100. doi:10.14573/altex.1503241

Hartung, T. (2021). Pyrogen testing revisited on occasion of the 25th anniversary of the whole blood monocyte activation test. ALTEX 38, 3–19. doi:10.14573/altex.2101051

Brown, J., Clippinger, A. J., Fritz Briglia, C. et al. (2021). Using the monocyte activation test as a stand-alone release test for medical devices. ALTEX 38, 151–156. doi:10.14573/altex.2012021

Thurman, T. L., Lahti, C. J., Mateffy, J. M. et al. (2023). Comparison of pyrogen assays by testing products exhibiting low endotoxin recovery. ALTEX 40, 117–124. doi:10.14573/altex.2202021