GenEdit, a biotech startup based in South San Francisco, has raised $26 million in series A financing to develop polymer nanoparticles for delivering therapies based on RNA and DNA into the body. The investment, by Eli Lilly and Company and nearly a dozen private investment firms, is a bet that GenEdit’s approach is an alternative to the lipid nanoparticles and viral vectors that currently dominate RNA and DNA delivery.
The startup was founded in 2016 by a group of scientists who thought polymer nanoparticles could be a new way to deliver CRISPR gene-editing therapies. Niren Murthy, a bioengineer at the University of California, Berkeley, and his former graduate students Kunwoo Lee and Hyo Min Park, cofounded GenEdit to develop polymer nanoparticles that could carry the three components of a CRISPR therapy: a Cas9 enzyme that cuts a cell’s DNA, a guide RNA molecule that tells Cas9 where to cut, and a new DNA strand that is pasted at the site of the cut.
Their original nanoparticles relied on a gold core. Murthy’s team and their collaborators, who included CRISPR co-inventor Jennifer Doudna, tested them in mouse models of genetic brain and muscle diseases. Although the results were promising, GenEdit decided to ditch the gold core for human therapies because it ran the risk of damaging cellular DNA. For the past few years, GenEdit has worked to build a library of hydrophilic polymers as the basis for gold-free nanoparticles.
GenEdit’s new nanoparticles have two main parts: the hydrophilic polymer and small molecules attached to the polymer that can help the nanoparticles target certain cells, like neurons or lung cells. The company is working through thousands of combinations to find the best ones. “We can make thousands of the polymers a month. It is a very efficient process,” says Lee, who is the startup’s CEO.
Once the nanoparticles are made, GenEdit tests them in cells growing in a dish before selecting a smaller number to evaluate in mice and monkeys. So far, the firm has developed nanoparticles that travel to the lungs when injected intravenously and to the brain when injected into the spinal cord.
Lee says GenEdit has also expanded its delivery goal beyond CRISPR to any therapy based on RNA or DNA. That could include messenger RNA therapies, small interfering RNA therapies, and DNA-based gene therapies for rare diseases.
Romuald Corbau, GenEdit’s new chief scientific officer, says it will be easier to design and test large numbers of polymer nanoparticles than the adeno-associated virus (AAV) vectors commonly used by gene therapy companies, including two companies he worked at: Freeline Therapeutics and Spark Therapeutics. “The simplicity of the nanoparticle is amazing,” he says.
Although a few commercial therapies already use polymer nanoparticles to deliver chemotherapies or anti-inflammatory drugs into cells, scientists have yet to make a successful polymer nanoparticle for delivering therapies based on RNA or DNA.