Optimizing and manufacturing your mRNA therapeutic is a multi-step journey. In addition to decisions about the manufacturing process itself, your team will need to determine the appropriate manufacturing quality grade and analytical testing panel. As the industry leader in mRNA, TriLink offers support and guidance at every step of your custom mRNA program.
The mRNA manufacturing process flow is dependent on which capping method is used. Post-transcriptional capping requires purification and capping steps that are not necessary for co-transcriptional capping, adding time and complexity to the process.
mRNA Manufacturing Process: Post-Transcriptional Capping
mRNA Manufacturing Process: Co-Transcriptional Capping
Sequence Optimization & Chemical Modifications
While not technically part of the manufacturing process, sequence optimization and selection of chemical modifications are important to define at the start. Strategic design of the mRNA sequence can enhance stability and translation in vivo, necessary qualities for an mRNA therapeutic. Both synonymous codons and modified NTPs can be utilized as strategies to deplete uridine content, thus reducing mRNA immunogenicity and improving translation. TriLink offers a wide catalog of modified NTPs for mRNA design, including pseudouridine triphosphate, N1-methylpseudouridine triphosphate, and 5-methoxyuridine triphosphate. Custom NTPs are also available.
Most mRNA therapeutics are produced by transcribing a linearized plasmid DNA template. In order to scale up manufacturing of mRNA, a suitable supply of plasmid DNA is necessary. E. coli containing the plasmid are expanded in a bioreactor via fermentation, and then harvested to produce purified plasmid. TriLink offers a plasmid manufacturing process that is optimized for downstream use in mRNA therapeutics, providing clients with a streamlined end-to-end manufacturing solution.
In vitro transcription is a well-established method of synthesizing mRNA. Mimicking the process in vivo, mRNA is produced by T7 RNA polymerase from a linearized DNA template, most often a plasmid. The poly A tail can be encoded in the template or may be added enzymatically post-transcription. Modified nucleoside triphosphates can be included in the reaction in addition to the standard nucleoside triphosphates, enabling chemical modification of the final mRNA. With decades of experience as an mRNA CDMO, TriLink is capable of supporting even the most complex mRNA manufacturing projects.
A 5’ cap structure is naturally added to mRNA synthesized in vivo. This cap must be added to synthetic mRNA as well, to prevent immune system recognition and enhance translation. There are co-transcriptional capping methods that add the cap during the in vitro transcription step, as well as post-transcriptional capping technology. Selecting a co-transcriptional capping method reduces the total number of manufacturing process steps, shortens the overall timeline, and improves yield. Enzymatic capping enzymes can also add significant expense to the manufacturing process. Legacy co-transcriptional capping methods such as anti-reverse cap analog (ARCA) generate a non-native Cap 0 structure, while TriLink’s CleanCap® capping technology generates the desirable natural Cap 1. Several CleanCap analogs have been developed, enabling the selection of the appropriate AG, AU, or GG start for your sequence.
After certain manufacturing steps it is important to purify the mRNA. Purification removes unwanted materials such as salts, cap analogs, NTPs, proteins, residual DNA, and dsRNA. There are several methods for purification available, but the process selected must meet your product and scale requirements. Silica membrane purification is not scalable to large quantities, so most commercial mRNA manufacturing relies on process chromatography methods for purification.
Quality Control & Release
Depending on your final mRNA application and clinical stage, the quality control testing requirements may vary. It is critical that your quality team determine the appropriate testing and specifications for your application and development stage. Some examples of mRNA-specific quality control testing include capping efficiency, poly A tail length, and residual plasmid DNA. TriLink offers a recommended mRNA analytical panel that can be customized to your specific requirements.