Unlocking the Power of RNA: Overcoming Manufacturing Challenges
Why we invested in EnPlusOne
When I first joined Breakout Ventures in October of 2021, I knew the future of RNA therapeutics was bright. Having been in graduate school during the COVID pandemic, mRNA vaccines were on my mind, not only as an eager twenty-something ready to get back to normalcy, but also as a budding organic chemist trying to understand the future of medicine. I was bullish, not only on mRNA as a new modality in therapeutics, but RNA as a modality period.
RNA therapeutics have the potential to treat a wide range of diseases in a precise and targeted manner. Unlike traditional small molecule drugs that often have off-target effects, RNA therapeutics can be designed by the rules of DNA and RNA to selectively silence or activate specific genes coding for proteins involved in disease processes. RNA therapeutics have the potential to treat diseases that have been historically difficult to target, such as genetic disorders, certain types of cancer, and even HIV. They can be personalized for a patient’s unique genetic makeup which could lead to more effective treatments and better patient outcomes. As research in this field continues to advance, RNA therapeutics offer the promise of a new era of personalized medicine that has the potential to revolutionize the way we treat disease.
I was curious about how we’d make all the RNA needed to drive this revolution. It turns out, there are two main methods of RNA synthesis used today, chemical and enzymatic, and both face challenges and limitations in manufacturing.
Chemical synthesis, also called phosphoramidite synthesis, involves the stepwise sequential addition of nucleotide building blocks where three chemical steps add one new nucleotide. This approach typically uses protected nucleotide building blocks and reactive intermediates, to add nucleotides to a growing RNA chain. Chemical synthesis can be used to produce RNAs of varying lengths and complexity, including modified nucleotides that are not typically found in natural RNA. There are lots of inherent challenges in phosphoramidite chemistry. The reactions must be rigorously kept away from water and require lots of toxic, explosive organic solvent — resulting in high waste and extraordinary costs. However, the largest commercial challenge with chemical synthesis is a frustrating one: it doesn’t scale well. For context, a 5.0 kilogram batch of RNA oligos consumes about 100,000 liters of acetonitrile, a commonly used organic solvent. For comparison, a 5.0 kilogram batch of small molecules typically consumes between 1 to 100 liters of organic solvent. Additionally, many of the chemicals used in chemical synthesis are toxic and bad for the environment, making handling and disposal tough challenges.
