The crabs’ copper-rich blood clots in the presence of bacterial endotoxins and has long been used in tests to detect contamination in shots and infusions.
More recently, man-made versions called recombinant Factor C (rFC) from Basel-based Lonza and others have emerged.
An industry battle has been brewing, as another testing giant, Lonza’s U.S.-based rival Charles River Laboratories,, has criticized the synthetic option on safety grounds.
Maryland-based U.S. Pharmacopeia (USP), whose influential publications guide the drug industry, had initially proposed adding rFC to a chapter governing international endotoxin testing standards.
USP is now ditching that, it announced late Friday, citing comments it had received from unidentified stakeholders.
The decision means the drug industry will have fewer incentives to end its reliance on animal-based tests, even as companies like Lonza, Eli Lilly and France’s bioMerieux promote man-made alternatives and wildlife advocates worry about crab bleeding’s effect on the coastal ecosystem.
“The Expert Committee decided to cancel the proposal,” USP said, adding it will instead create a new, stand-alone rFC chapter come May 2022. It did not immediately give specific reasons for why it canceled the original plan.
The group’s shift means drug companies seeking to use synthetic products must still do extra, costly validation work to guarantee they match the safety of the crab blood. Despite the move, USP did say it still supports efforts to shift to rFC tests, including for potential COVID-19 tests where it is offering technical assistance.
Eli Lilly, one drugmaker that has shifted to synthetic tests, has said rFC is safe and that the extra validation requirements have been a hurdle to more companies adopting it.
Endotoxin tests number 70 million annually and estimates put the relevant market at $1 billion annually by 2024.
Conservationists, including advocates for migratory birds that dine on horseshoe crab eggs on the U.S. East Coast, have also been pushing for rFC recognition to take pressure off crabs, some of which still die after being released into the Atlantic Ocean following bleeding.
Lonza did not immediately comment on USP’s move.
Charles River also did not return a request for comment.
The New Jersey Audubon Society and Delaware-based Ecological Research & Development Group, a crab conservation group, did not respond to messages seeking comment.
Europe’s drug standards group EDQM in Strasbourg, France, also did not immediately return Reuters messages seeking comment on how the USP move would impact its own separate plans to recognize rFC as on par with crab blood tests.
