A company harnessing computation and advanced chemistry to design drug delivery systems has raised £7.8 million funding.

Sixfold Bioscience, headquartered in London, was founded in 2017 by Dr George Foot, Dr Anna Perdrix Rosell and Zuzanna Brzosko. It has a current focus on short interfering RNA for gene silencing and messenger RNA for gene expression. 

Although rapidly expanding within the last couple of years, the RNA therapeutics field is still largely constrained to targeting the liver or local administration. Sixfold’s Mergo platform is looking to expand this therapeutic approach to other organs.


Mergo consists of the RNA therapeutic and biocompatible building blocks that modulate the pharmacokinetic and pharmacodynamic properties of the system to target selected cell types.

The building-blocks that form Mergo are computationally screened, assembled using high-throughput chemistry, and then tested, with each iteration feeding into the next. 

In essence, the Mergo system rapidly learns which is the best combination for delivery to a given tissue.

Investors in the seed round included Cantos Ventures, Y Combinator, Lombard Street Ventures and Pi Campus, as well as select angel investors. The company received further non-dilutive funding from Innovate UK, MedCity, and the European Commission, where the team leads a series of collaborations on RNA therapeutics.

“This substantial seed financing is testament to the incredible progress the R&D team has made on the Mergo system to date, and will crucially enable us to expand our platform across several therapeutic indications,” said co-CEO Dr Foot.

Ian Rountree, founder and general partner at Cantos Ventures, said: “The global pandemic has catapulted RNA therapeutics into the mainstream, yet 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. 

“We are delighted to support the Company in this seed round and look forward to their rapid progress over the coming years.”

Former CEO Brzosko left the company in 2020 and is now director of corporate strategy and external innovation at Eli Lilly and Company.