Researchers have leveraged antibodies from a man who self-injected snake venom multiple times to develop a potential universal antivenom. This experimental antivenom shows promise against several Australian snake species, including taipans, tiger snakes, and king brown snakes, demonstrating a proof-of-concept for broader effectiveness.
Combining antibodies from the man's blood with an existing toxin inhibitor, the researchers achieved broad protection against various elapid snakes. The study, published in Cell, suggests a potential solution for all Australian elapid snakes.
Professor Bryan Fry, a venom expert, raises concerns about the limited cross-reactivity to Australian snakes, citing the non-Australian origins of the venom used for self-injection. He also highlights the ethical implications of the self-injection practice and expresses skepticism about the antivenom's complete effectiveness. He emphasizes that existing species-specific antivenoms remain crucial, especially in developing regions.
The researchers plan to test the antivenom on dogs, given their closer physiological similarity to humans compared to lab mice. While a fully universal antivenom is unlikely due to the complexity and diversity of snake venoms, the study represents a significant advancement towards broader protection.
Snake bites cause substantial mortality and disability globally, with up to 137,000 deaths annually. The development of more effective antivenoms is crucial to reduce this significant public health burden.
Combining that antibody with an existing toxin inhibitor called varespladib (which is already used in Australia) expanded protection to taipans and tiger snakes.
Adding a second antibody isolated from Friede’s blood called SNX-B03 offered complete protection against four snakes including the mulga, or king brown – a two-metre Australian native known to “hang on and chew” victims as it injects venom – but only partial protection for death adders, which are also native.
Glanville and his co-authors write in the resulting paper published in Cell on Saturday that their results show proof of principle for building a universal antivenom.
“Australia has many venomous species of snake, but they are all of the neurotoxic ‘elapid’ type,” Glanville said. “Our Cell study presents a broad solution to elapids. Therefore our cocktail is potentially relevant to all Australian snakes.”
University of Queensland venom expert Professor Bryan Fry, however, believes the treatment would have “patchy” coverage against Australian snake bites given the ad-hoc way Friede injected himself over the years, mostly with the venom of US and exotic species.
“There would be very, very limited cross-reactivity to anything Australian, which is reflective of the fact that he injected himself with snakes that are common on the US pet trades, such as mambas and cobras,” Fry said.
“If they’re having poor cross-reactivity with death adders, I wouldn’t expect better cross-reactivity with even more divergent kinds of snakes. There’s definitely going to be limits.”
Fry also said there was a “zero chance” a university ethics unit would’ve approved the injection of snake venom into a human under scientific circumstances.
Friede injected the venom of his own volition and had given up the practice in 2018, before the researchers began studying his blood.
Glanville said an Australian vet approached him after he presented Centivax’s early findings from the study on Friede at a venom conference, and said she was interested in trialling the treatment at her network of clinics.
The trial hasn’t been confirmed, but the researchers want to test the experimental antivenom in bitten dogs because they’re more similar in body weight and heartbeat to humans in comparison to lab mice.
Current antivenoms are generally specific to one, or just a handful, of species. Melbourne’s Commonwealth Serum Laboratories make them using venom milked and dehydrated by staff at the Australian Reptile Park near Gosford, north of Sydney.
To make antivenom, small amounts of venom are injected into an animal such as a horse over several months. Antibodies build up in the horse’s bloodstream and are extracted to make vials of treatment serum.
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Treatments that work across multiple species are desperately needed given victims often can’t identify what kind of snake they copped a bite from. But is a universal antivenom ever likely to fully replace species-specific serum?
“Realistically? No, because venoms are so extraordinarily complex and so tremendously divergent,” Fry said.
Existing antivenoms remain the cheapest and safest way to treat bites for developing regions in sub-Saharan Africa and South-East Asia, where the most people die from snake bites, he added.
Snake bites kill up to 137,000 people per year and permanently disable 300,000 people, often through amputation.
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