Moving beyond Cas9, Excision licenses CRISPR gene editors

The UC Berkeley team sees the discoveries leading to valuable genome editing tools.

Excision BioTherapeutics has licensed recently discovered CRISPR gene editors from UC Berkeley. The deal gives Excision the exclusive right to use the Cas9 alternatives to treat infectious diseases. 

Philadelphia-based Excision, like other CRISPR biotechs, uses Cas9 to make the breaks in DNA that are essential to its therapeutic approach. Cas9 became established at the forefront of the CRISPR gene editing boom because it is made by bacteria isolated by researchers. But, as a UC Berkeley team showed in February, microbes collectively have a larger toolkit.

Excision’s deal with UC Berkeley clears it to use these recently discovered gene editing tools in the treatment of infectious diseases, the biotech's area of specialization. The company thinks the tools will open up new ways to tackle viruses including herpes and hepatitis B.    

“These newly discovered gene editors have the potential to offer flexibility and complementary gene editing approaches beyond the currently employed CRISPR/Cas9,“ Kamel Khalili, Ph.D., a professor at Temple University and co-founder of Excision, said in a statement.
Excision plans to use the editing tools to grow its own pipeline and make money by sublicensing them to other drug companies. 

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The license was made possible by research published by Jennifer Doudna, Ph.D., and colleagues earlier this year. Moving beyond the isolated bacteria that yielded Cas9, the UC Berkeley team used metagenomics to look for gene editing tools made by the huge numbers of uncultivated microbes. That led to the discovery of Cas9 made by an archaeon and two new bacterial systems: CasX and CasY.

Doudna and her collaborators talked up the research applications of the discoveries.

“The small number of proteins that are required for interference and their relatively short length make these systems especially valuable for the development of genome editing tools,” the authors wrote.

Excision will now investigate the tools in parallel to its Cas9-enabled projects. The lead candidate from the Cas9 research is EBT101, a drug designed to use gene editing to eradicate HIV provirus from the body. Excision plans to move into the clinic next year.