Inside exosomes: Nature’s drug carriers

Imagine a payload being delivered to the target tissue by a biological, non-toxic transport system. Imagine a drug traveling to the central nervous system without the need for invasive injections or without side effects caused by its untargeted, undesirable reach. Imagine a payload reaching the intended cells through a mechanism that is natural, that can be administered more than once, and is adaptable across applications.

No need to imagine, these possibilities are already being explored by biotech companies developing exosomes (also known as extracellular vesicles) as carriers for a wide range of therapeutics.

What are exosomes?

Exosomes are tiny vesicles (typically ~30–150 nm in diameter) naturally released by cells. They form inside endosomal compartments and are secreted into the extracellular space, where they participate in intercellular communication by transporting lipids, proteins, and nucleic acids (including mRNA and microRNA) between cells. 

As naturally occurring extracellular vesicles, they are inherently biocompatible and typically exhibit low immunogenicity, reducing the likelihood of adverse immune responses and potentially enabling repeated administration, both relevant limitations for viral vectors used today in gene therapies. While lipid nanoparticles (LNPs), which are also currently used as carriers of genetic payloads in molecular therapeutics, rely on synthetic design and often show preferential accumulation in organs such as the liver, exosomes can display intrinsic tissue tropism derived from their parent cells. Because of this, they offer a more biologically guided form of targeting. Exosomes’ endogenous origin also confers a degree of biological “stealth,” allowing them to circulate and interact with cells without being detected and/or eliminated by the immune system.

Targeting the CNS with exosomes

The central nervous system (CNS) represents the holy grail of drug delivery challenges. The blood–brain barrier (BBB) is a highly selective semipermeable border that prevents most compounds from entering the brain, protecting it from toxins and pathogens but also blocking therapeutic agents. Traditional approaches require invasive intrathecal or intracranial injections, which carry significant risks and limit treatment accessibility. This is why many exosome startups prioritize CNS applications.

The natural ability of certain exosomes to traverse the BBB offers a non-invasive route for delivering therapeutics directly to brain tissue. As such, Belgian company EXO Biologics has developed a production platform that enables scalable manufacturing of exosomes with CNS tropism. The company recently announced two new collaborations that will advance toward clinical development for Parkinson’s and multiple sclerosis.

On its part, UK-based Evox Therapeutics has taken this further with ExoEdit, a proprietary genome-editing technology that harnesses exosomes to deliver CRISPR-based editing tools into specific brain cells. “Our pipeline programs are delivering gene editors as ribonucleoproteins inside of exosomes, which gives rapid onset of pharmacology and rapid clearance of the editing machinery, meaning that we have a very efficient delivery modality with an excellent safety profile,” said Per Lundin, CEO of Evox, to European Biotechnology Magazine. He also explained that the team is currently completing IND-enabling non-human primate studies, in which early data have demonstrated robust target editing in the striatum of Huntington’s animal models. “We are tracking toward dosing the first Huntington’s patients in a Phase 1/2 first-in-human trial in 2027,” added Lundin.

Aruna Bio, with dual headquarters in Boston and Athens, made headlines in 2024 as the first company to advance an exosome-based therapy into human clinical trials with its lead candidate, AB126, for acute ischemic stroke. Latest updates from 2025 indicate that the program has successfully progressed to Phase 1b, marking a significant milestone in demonstrating the safety and tolerability of exosome delivery.

Adding to the European and global momentum, NurExone Biologic, with operations in Israel and Canada, is leveraging its proprietary ExoNucleo platform for the treatment of neurodegenerative diseases. Its lead candidate, ExoPTEN, delivers siRNA designed to silence PTEN expression in damaged spinal cord neurons, with first-in-human studies expected in 2026. The company describes the approach as harnessing “Nature’s Guided Missiles.”

In an email exchange with EBM, Anton Hutter, PhD, a patent attorney on the Chemical & Life Sciences team at Venner Shipley, noted that many patent applications now focus on CNS-targeting exosomes, particularly in areas where LNPs and AAVs have historically struggled. “I would not be surprised if exosomes become the preferred delivery modality for CNS applications or for those requiring repeat dosing,” he said. Despite this, other companies are harnessing the versatility of exosomes to target a broad range of diseases beyond the CNS.

Beyond the brain: other targets

In France, EVerZom is pioneering exosome-based therapies for tissue regeneration and repair. Their pipeline targets the healing of digestive tissues, with Crohn’s disease-associated fistulas as a primary indication. By harnessing the regenerative properties of exosomes, EVerZom aims to promote tissue closure and reduce inflammation in the gut, offering a potential alternative to surgical interventions. According to the company’s website, its platform is “protected by several patents, covering the entire technological value chain: cell sourcing, exosome generation, exosome loading, and formulation.”

Another French innovator, Ciloa, is using exosome technology for obesity and type 2 diabetes. Last year, it secured funding to advance its lead candidate, APN-sEV, up to Phase 2a trials and support GMP-scale manufacturing.

Beyond Europe, ILIAS Biologics, a South Korean company, is advancing ILB-202, an exosome-based therapeutic candidate for inflammatory diseases. In a January 2026 presentation, the company reported that ILB-202 demonstrated a favorable safety and tolerability profile in a Phase 1 trial involving healthy volunteers. Based on these findings, ILIAS is now exploring expansion into multiple inflammatory indications.

On the vaccine front, across the Atlantic, Capricor Therapeutics is collaborating with the National Institutes of Health (NIH) to investigate its proprietary StealthX exosome-based vaccine platform for the prevention of SARS-CoV-2 infection. The StealthX platform is designed for engineered protein surface expression, cargo loading, and targeted delivery using exosomes, which is also being investigated for precision therapeutics.

The European exosome landscape

“Europe has a highly competitive, IP driven exosome ecosystem with strong early positioning,” said patent attorney Hutter. “I predict that the next 5–10 years will be defined less by discovery and more by IP consolidation, oppositions, and manufacturability breakthroughs.” 

Hutter noted that many companies are currently seeking expansive patents in exosome technology, but the strength and enforceability of those patents will likely face significant legal and regulatory scrutiny after issuance. “Exosome companies entering the market should assess their freedom-to-operate risks, identify any dominant patents and patent applications that may block their route to market, and determine which may need to be licensed or challenged before the company can proceed,” he said. In his view, the field is unlikely to produce broad patents covering exosomes as universal delivery platforms; instead, intellectual property is expected to become increasingly indication-specific, with the greatest value residing in narrowly targeted and defensible therapeutic applications.