The company uses a novel, cell-free approach to produce viral vectors for gene therapy
Danish start-up Fuse Vectors has received $5.2 million in preseed financing to further develop their gene therapy technology. The company has developed a cell-free platform for producing adeno-associated virus (AAV) vectors for use in gene therapy. Co-CEO and cofounder Jordan Turnbull says that current AAV production processes are “bottlenecking the true potential of gene therapies” and that the company’s process is “able to unlock certain areas that were previously inaccessible with current-generation manufacturing technologies.” Back in 2022, Turnbull and co-CEO Benjamin Blaha, who both have backgrounds in pharmaceuticals and biotechnology, set up a small laboratory using some family funding to try to solve that problem. While they were living off savings, the two developed their process for assembling AAV capsids in a cell-free environment and sought support from the BioInnovation Institute in Copenhagen, Denmark, a start-up incubator financed by the Novo Nordisk Foundation. The pair was joined by Henrik Stage, and the three officially cofounded Fuse Vectors, which emerged from stealth around 1 year ago. By late 2024, the company had matured to the point of developing a relationship with venture capital firm HCVC. Blaha says the company’s approach takes the AAV assembly process outside of the cell. The exact biochemistry underlying the process is a trade secret, but the high-level view is that the AAV capsid, nucleic acids, and packaging proteins can first be efficiently produced inside of cells. But then the process of assembling those components, which is inefficient in a cellular environment, instead takes place in vitro to create filled capsids. Blaha says going cell-free allows the scientists to start pushing the conditions for assembly beyond what a cell would tolerate. “We're no longer constrained by a certain pH or temperature around 37 °C,” he says. Removing those biological constraints has helped result in a much more efficient AAV assembly process, he says. “Right now, we're at a space where we can fill 99% of our capsids quite reproducibly in a single 4 h step, rather than having multiple weeks of culturing time and processing,” Blaha says. That speed up in the process allows the company and its partners to test different combinations of AAV capsid serotypes and payloads at a scale that was previously not possible. “One of the things that we can offer at a very early stage, for drug discovery stage initiatives, is we can really screen unconstrained all possible candidate variants,” Blaha says.