Sixfold bags VC funding to expand RNA delivery beyond the liver

December 7, 2022

London, United Kingdom

Sixfold Bioscience has secured funding to support its effort to deliver RNA to previously untargetable tissues, pulling in $10.5 million from backers including Y Combinator and Cantos Ventures.

Delivery is a long-standing challenge for RNA therapies, with tissue bioaccumulation hindering work to get the nucleic acids to cells beyond the liver. Sixfold is one of a number of companies working to create a delivery system that is safe and has a wide enough therapeutic window outside the liver. If successful, the delivery projects could unlock the therapeutic potential of RNA.

Working out of London, Sixfold’s attempt to improve the delivery of RNA has caught the attention of investors. Y Combinator, Cantos Ventures, Lombard Street and Pi Campus came together to provide seed funding, setting Sixfold up to continue developing its Mergo RNA delivery platform.

“The field is constrained to targeting the liver. Sixfold's iterative platform technology and use of machine learning will unlock the power of mRNA and RNAi for many diseases across various tissue types,” Ian Rountree, founder and general partner at Cantos, said in a statement.

Sixfold’s approach begins with the use of machine learning to screen a chemical space for possible constructs. The RNA therapeutic and construct are then assembled and tested, with the data feeding back into the machine learning screen. Sixfold has designed the system to work with various payloads, including mRNA and RNAi, and to optimize biocompatibility to ensure safety.  

George Foot, founder and co-CEO of Sixfold, said the funding is big enough to enable the company to expand the platform across “several” therapeutic indications. Sixfold is yet to share full details of its therapeutic focus but has revealed an interest in using siRNA to treat cancer.


Sixfold Bioscience is a venture-backed preclinical-stage biotechnology company, founded in 2017, based at the Translation & Innovation Hub in White City, London. Sixfold develops programmable drug delivery systems, with a current focus on siRNA and ASO.

Sixfold’s RNA delivery platform, Mergo®, was conceived by co-founders Dr Perdrix Rosell and Dr George Foot, who were left frustrated by current delivery systems that were either too toxic or faced complex engineering challenges. The Company’s differentiated approach is based on engineering biocompatible nano-architectures with precise chemical profiles that guide the RNA to selected organs.

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