TheraXyte and NIFDC Achieve Breakthrough with Engineered EV Platform ExoBoost 2.0, Overcoming Key Clinical Translation Barriers

Recently, Beijing TheraXyte Biotechnology Co., Ltd., in collaboration with the Division of Recombinant Drugs at the National Institutes for Food and Drug Control (NIFDC), published a research paper titled “Developing High-Yield and Safe Therapeutic EVs by Ablating Tissue Factor-Mediated Toxicity” on BioRxiv. This study successfully established the ExoBoost 2.0 technology platform, overcoming two major bottlenecks in clinical translation: the large-scale production of therapeutic extracellular vesicles (EVs) and the safety of systemic administration. This breakthrough lays a critical foundation for EVs to become the next-generation drug delivery platform, marking that China’s research in this field has reached an internationally advanced level.

Amid the rapid advancement of gene therapy, current mainstream delivery systems such as adeno-associated viruses (AAV) and lipid nanoparticles (LNP) face numerous limitations, including limited packaging capacity, high immunogenicity, and insufficient targeting. In contrast, extracellular vesicles (EVs), with their unique advantages of low immunogenicity, ease of engineering, and cargo protection, have emerged as a highly promising novel delivery platform. However, the clinical translation of EVs has long been constrained by two core challenges: excessively low yields that fail to meet therapeutic dosing and scalable production requirements, and the risk of unexplained acute toxicity associated with high-dose systemic administration. These two bottlenecks severely hinder their clinical application.

To address the aforementioned challenges, a joint research team composed of TheraXyte Biotech and the Recombinant Drug Division of the National Institutes for Food and Drug Control (NIFDC) conducted in-depth exploration and identified a key solution. Regarding yield enhancement, the team discovered that GPI-anchored proteins serve as the core "switch" driving extracellular vesicle (EV) biosynthesis. Upon expressing the GPI-anchored proteins CD55 and CD59 in HEK293T cells, EV production was significantly increased; experiments constructing truncated variants of CD55 further confirmed that the GPI anchor structure is critical for boosting yield. Based on these findings, the team stably expressed the high-efficiency variant TR3 in Expi293F cells, successfully establishing the ExoBoost cell line, which increased EV production by more than 50-fold.

In terms of safety optimization, the joint team identified the root cause of toxicity through a series of ingenious experiments. The study found that high-dose intravenous injection of extracellular vesicles (EVs) induced acute lethal toxicity in mice within 30 minutes, whereas intraperitoneal injection of the same or even higher doses caused no adverse reactions, with the toxicity being dependent on the protein components on the EV surface. Further research confirmed that tissue factor (TF) is the core mediator triggering acute coagulation toxicity; EVs derived from keratinocyte stem cells (KSCs), which naturally express high levels of TF, could cause mouse death even at low doses. More notably, the TF expression level in EVs derived from mesenchymal stem cells (MSCs), commonly used in clinical practice, is significantly higher than that in ordinary cells, suggesting potential risks of coagulation toxicity associated with high-dose systemic therapy.

In light of this finding, the joint team employed CRISPR/Cas9 gene-editing technology to knock out the F3 gene encoding tissue factor (TF) in the ExoBoost cell line, while preserving its high-yield production of GPI-anchored proteins, thereby successfully constructing a novel ExoBoost 2.0 cell line. Performance validation demonstrated that extracellular vesicles (EVs) produced by this cell line exhibited an approximately 100-fold increase in yield compared to the original cell line and were completely free of TF. Even after intravenous injection of an ultra-high dose of up to 1.5×10¹² particles in mice, no adverse effects or acute lethal toxicity were observed, thoroughly resolving the safety concerns associated with systemic EV administration.

Even more encouragingly, the study also reveals a breakthrough delivery strategy for high-dose EVs—"dose-saturation clearance." Within one hour after low-dose EV injection, they are rapidly cleared by the liver and spleen. In contrast, high-dose EVs can temporarily "saturate" the hepatic and splenic clearance systems, significantly prolonging their circulation time in the bloodstream and enabling efficient distribution to hard-to-reach tissues such as muscle and brain. Notably, brain exposure increased approximately 30,000-fold compared with the low-dose group, and the EVs successfully crossed the blood–brain barrier and colocalized with neurons in the cerebral cortex, opening up an entirely new avenue for the treatment of central nervous system diseases. Furthermore, experiments involving repeated high-dose injections over six consecutive weeks confirmed that ExoBoost 2.0 EVs did not elicit significant humoral immune responses or tissue inflammation, further validating their safety for long-term use.

As the first enterprise to collaborate with the National Institutes for Food and Drug Control (NIFDC) to publish significant research findings in this field, Beijing TheraXyte Biotechnology Co., Ltd. has not only established an industrial foundation for large-scale EV production and safety control through the successful development of its ExoBoost 2.0 platform, but its proposed high-dose delivery strategy also holds revolutionary significance.

The study also recommends incorporating quantitative tissue factor (TF) assessment into mandatory quality control standards for clinical-grade extracellular vesicles (EVs), providing a significant reference for the standardized development of the industry. Looking ahead, the joint research team will further develop high-efficiency drug-loading technologies, enhance targeting specificity, and comprehensively evaluate the potential impacts of long-term repeated dosing, thereby accelerating the clinical translation of the ExoBoost 2.0 platform. This innovative achievement not only provides robust technical support for EV-based drug delivery systems but also holds promise for revolutionary breakthroughs in the treatment of refractory diseases, such as those affecting the central nervous system, highlighting China’s independent innovation capabilities in the field of biomedical engineering.