Melbourne biotech Exopharm has solved a crucial bottleneck in the production of exosomes, creating an easily scalable technology to purify exosomes that may have momentous potential in regenerative medicine.
There’s a lot of excitement in the field of regenerative medicine about exosomes, nano-vesicles secreted by cells for intercellular signaling that have been found to stimulate tissue regeneration.
Exopharm managing director and founder Dr Ian Dixon calls exosomes the “secret sauce” of stem cells, and says exosomes have promise to deliver targeted medicine and fighting age-related diseases.
But purifying these exosomes – also known as extracellular vesicles (EVs) – so they can be made in sufficient scale to be used as a new form of medicine has always been an issue.
“Everyone knows that EVs have magical properties,” he says.
“The biggest problem is to purify the EVs from their source and to eliminate the contaminants, and not damage the EVs,” he says.
The most commonly used method today, spinning exosomes in an ultracentrifuge, has major issues of scalability, can damage the vesicles and is time-consuming.
Dr Dixon, also the co-founder of Melbourne stem cell manufacturing company Cynata Therapeutics, said he spent three years working on solving this purification issue with his colleagues.
After a number of false starts the team went into “shotgun mode”, trying everything at once. They eventually realised there was a way to load liquids containing exosomes through a chromatography column – a device used to separate chemical compounds – loaded with an inexpensive polymer charged to attract exosomes. The exosomes are retained while the rest of the biological detritus is simply washed away.
Exopharm calls this purification method LEAP – Ligand-based Exosome Affinity Purification – and it’s applied for a patent on the specific chemicals used in the process.
It’s a real breakthrough because it’s so scalable, says Exopharm chief commercial officer Dr Chris Baldwin.
“One of the great things about the process that the team has designed is, is that all we need to scale is bigger equipment,” he said.
“We don’t need to add time, we don’t need to change the process.”
The chromatography columns Exopharm is using now to produce the small doses needed for its clinical trials are small enough to hold in your hand, he said.
But industrial-sized columns are readily available that easily could produce enough exosomes for millions of doses.
Commercial excitement about exosome medicines
There’s a lot of excitement around exosomes at the moment. To give one example: as of 2008, there had been just 675 scientific papers mentioning exosomes published, according to the National Library of Medicine’s Pubmed search engine.
In 2019 there were 3,213 exosome papers – with another 3,586 published so far in 2020, according to a PubMed search.
Cambridge, Massachusetts-based Codiak BioSciences went public on the NASDAQ last month under symbol CDAK, making it the second exosome company behind Exopharm to list.
Dr Baldwin recently presented at a Boston-based virtual exosome conference, explaining how the company used LEAP to purify exosomes from blood platelets for a clinical trial, the company’s second.
Participants in this phase 1 clinical trial will receive a small puncture biopsy in each of their shoulders – one treated with the company’s Plexaris exosome product and the other treated with placebo in the other shoulder for the phase 1.
“The thing about exosomes is that they’re new,” Dr Baldwin said, so Exopharm wants to build up a body of evidence to convince regulators that introducing the novel vesicle products into human bodies is safe.
“We’re really excited about just ticking the box on this on the way to the next study and the next study,” he said.
“These are very exciting times for young biotechs.”
Source – Stockhead