Crab blood remains vital in America for drug and vaccine-making

by Sara Floyd Hello

Fishermen catch hundreds of horseshoe crabs as they crawl onto shore to mate, every April in South Carolina. An American pharmaceutical company, in Charleston the crabs are transported to labs owned by Charles River.

There they are strapped and, still alive, drained of about a third of their blue-coloured blood to steel countertops. Then they are returned to the ocean. For America’s biomedical industry this liquid is vital. For as much as $15,000 a litre of it goes.

On the horseshoe crab parts of modern medicine unusually have been reliant. An extract that detects endotoxin, a nasty and sometimes fatal chemical produced by certain bacteria, its blood is the only known natural source of limulus amebocyte lysate (lal).

To ensure the safety of medicines and implanted devices drug firms use antibiotics, anti-cancer drugs, heart stents, insulin and vaccines. By giving a visual signal of unwanted contamination the immune cells in the crab’s blood clot around toxic bacteria.

Demand for the blue liquid soared, as pharmaceutical companies ramped up production of the covid-19 jab. Nearly 650,000 crabs were bled in America in 2020, 36% more than in 2018.

Bleeding is not without harm to the crabs. Conservationists estimate that on release between 5% and 30% of them die. Biologists have found that, once bled, females become lethargic and have trouble following the tides to egg-laying areas at the University of New Hampshire.

The International Union for Conservation of Nature listed them as “vulnerable” to extinction in 2016. It blamed overharvesting for use as food, bait and biomedical testing, as well as habitat loss. This also hurts other species. In horseshoe-crab eggs in Delaware Bay, a stopover the red knot, a bird that migrates from South America to the Arctic tundra, is endangered largely because of the decline.

America’s biomedical industry will face a crunch as crab numbers fall and demand for lal rises. Plenty of routine surgical procedures such as hip replacements, whose numbers are growing but to do so billions of covid-19 vaccinations have relied on it.

Using the extract produced at their facility in Charleston, one of four manufacturers of lal in America, Charles River, estimates that 55% of injectable pharmaceuticals and implanted devices globally are tested.

In Europe is rapidly replacing crab blood as the industry standard for testing yet a synthetic alternative to lal is already available. A Swiss biotech company, Lonza, cloned crab DNA to create recombinant Factor c (rfc) in 2003.

Jay Bolden, an avid birdwatcher and biologist, pioneered the use of rfc in America at Eli Lilly, a pharmaceutical company, troubled by the red knot’s decline. In 2017 in a study published Mr Bolden found that rfc detected endotoxins as well as lal, or even better. The test turned up fewer false positives and, moreover, to produce was cheaper.

With rfc that year Eli Lilly vowed to test all new products; instead of lal 80% of the company now uses it. A French pharmaceutical firm, Sanofi, is also making the switch at their American plants.

America’s Food and Drug Administration (fda) approved the first medicine tested with rfc in 2018. Six more of Eli Lilly’s have since been authorized.

In Europe, China and Japan, pharmacopeias list rfc among their approved endotoxin-testing agents. To add the synthetic substance to its list the US Pharmacopeia (usp), a non-profit that helps set medical quality standards on which the fda relies, has been reluctant. To prove their safety to the FDA that means American firms that want to use rfc tests must work harder. Usp says that “one adverse incident might not only set back the adoption of rfc but could damage overall trust in vaccines or other injectables, already plagued by misinformation, to explain its hesitation.”

That holdup comes with its own costs. “We are doing damage to an endangered population and not using an alternative that is equally effective and could be mass-produced” more cheaply, Barbara Brummer, who previously worked at Johnson & Johnson and is now with the Nature Conservancy, an NGO, sums it up.

It has been a vocal critic of the synthetic option, on safety grounds; Charles River argues that supply fears are overblown, and that bleeding does little harm to crabs.

Mr Bolden reckons America’s other drug companies would swiftly turn away from lal but if usp approved synthetic testing. The next several rounds of covid-19 boosters produced will rely on the horseshoe crab in America. But such vampire-like dependence on its blue blood cannot last much longer.

Source:- https://bloggerstow.com/crab-blood-remains-vital-in-america-for-drug-and-vaccine-making/