BPR: In your opinion what are the benefits of enzymatically produced synthetic DNA over plasmid DNA?
There are fundamental issues with the use of plasmid DNA, not limited to the presence of bacterial backbone, antibiotic resistance genes and endotoxins, but also long lead times to produce large-scale (several grams) of clinical grade material that is GMP compliant. Plasmid DNA production involves bacterial fermentation in large-scale bioreactors that are often at risk of batch failures.
In addition, plasmid DNA-encoded homopolymeric sequences (poly(A) tails) recombine during bacterial amplification of the plasmid DNA, resulting in sequence instability and heterogeneity. These prevalent issues, combined with large footprint, often accompanied with low yields, can add extreme cost and time to this upstream step.
A final point to mention is the flexibility of batch size of synthetic DNA. 4basebio’s GMP compliant offering starts at 50mg, which is ideally suited for the personalised cancer vaccine (PCV) space. When using a plasmid alternative, clients often have to commit to significantly larger batches of DNA than required, due to inflexibility in bioreactor sizes.
BPR: What makes 4basebio unique in the field of synthetic DNA?
Owing to the flexibility of our DNA platform, 4basebio is unique in the fact that we can make DNA products that confer application specific benefits. For instance, in osDNA, we can incorporate modifications into the DNA backbone to regulate the immunostimulatory properties of the molecule, a desirable feature when developing a DNA vaccine.
Meanwhile, opDNA templates have an open 3’ end, and therefore, unlike a conventional plasmid or closed synthetic molecule, do not need to be enzymatically linearised prior to in vitro transcription (IVT), Another benefit is the efficient/reliable inclusion of longer ~120 poly(A) tails that is well established in the industry to enhance stability and translational capacity of the mRNA. Furthermore, IVT yields per mass of DNA are higher for synthetic DNA templates as, unlike plasmid DNA, they lack non-transcribing DNA backbone, resulting in an overall cost effectiveness.
Likewise, oeDNA has features incorporated that make it better suited for gene editing applications, whereas hpDNA is our preferred product for use in viral vector manufacturing.
Another differentiator in the space is the priming method by which we amplify DNA templates. Our proprietary Trueprime amplification engine omits the use of primers, allowing us to use less DNA template and conferring high fidelity, leading to a high quality, synthetic DNA product.
Finally, 4basebio doesn’t amplify any bacterial backbone in our manufacturing process, conferring cost and safety benefits, since no antibiotic resistance genes are amplified.
BPR: What does the future hold for synthetic DNA?
The C&G therapy and vaccine space remains buoyant, driven by some recent successes in AAV and gene editing therapies, along with the large-scale validation of mRNA based vaccines in response to the global COVID pandemic. Academic and industrial research into new therapies and vaccines is thriving, with the number of clinical trials continuing to rise sharply.
At the same time, the COVID pandemic also highlighted the necessity for increased global manufacturing capabilities, which has led to governments, leading contract manufacturers, as well as new entrants to invest significantly in building out their capabilities and increasing capacity. Despite the increased investment, demand has continued to outstrip supply, and plasmid DNA in particular remains a bottleneck in the development of new therapies.
We believe synthetic DNA presents a viable solution and is rapidly gaining momentum. AskBio, which is now part of Bayer, and Touchlight have both received regulatory approval for clinical trial for therapies manufactured with enzymatically produced DNA. Meanwhile, we have several clients expected to enter the clinic in the near term, in different geographical locations and in different application areas. Synthetic DNA confers many benefits over traditional plasmid DNA, not limited to speed, scale and safety profile.