2nd Version of the USP Draft Guidance on mRNA-based Therapeutics

The global market for mRNA therapeutics continues to expand as they are more effective, faster to develop and produce, and more flexible than traditional approaches. The development of effective vaccines to combat COVID-19 has demonstrated the potential of mRNA technology and paved the way for a number of novel vaccines and therapies. The development and production of vaccines based on this modality has proven to be faster than other methods, making mRNA a promising solution for combating future infectious diseases. mRNA-based therapeutics and preventive agents are in development for a variety of refractory diseases, including infectious diseases, genetic metabolic diseases, various cancers and cardiovascular diseases.

Because the application of mRNA technology is relatively new, regulatory guidelines and industry standards to govern non-compatible aspects of mRNA quality during development and manufacturing are still evolving. These include areas such as verification of identity, control of impurities and measurement of content for dosage. Without uniform methods for determining quality, developers and manufacturers of mRNA products must develop their own methods and protocols, which takes time and resources away from developing a unique mRNA technology. In addition, quality issues that are not properly identified during product development can compromise product quality, safety and efficacy, lead to poor clinical outcomes, cause costly delays and threaten regulatory approval.

In February 2022, the USP already published the first version of the draft guideline to solicit feedback from global stakeholders on the methods contained therein and to encourage the submission of alternative methods and additional supporting documentation. The initial guideline draft included methods taken from publicly available sources and was reviewed by a USP Scientific Expert Committee on Biologics, which included representatives from industry, government and academia. The document also included best practices described in two of the existing USP standards for vaccines in the United States Pharmacopeia-National Formulary, General Chapters <1235> "Vaccines for Human Use-General Considerations" and <1239> "Vaccines for Human Use-Viral Vaccines".

Change from the first version

In this second version, comments from the first version have been considered and new methods have been added. Major updates in this version include the following:

• RT-qPCR 
• Capillary electrophoresis (CE) 
• Capillary gel electrophoresis (CGE) for RNA size and integrity 
• IP-RP-HPLC method for determination of mRNA purity and percentage of mRNA fragments 
• SEC-HPLC and RP-HPLC for mRNA integrity 
• RP-HPLC-CAD for checking the identity and content of lipids 
• SEC-HPLC for quantification of mRNA aggregation 
• AEX-HPLC method for residual NTP and capping agent 
• RP-LC-MS/MS and DNAzyme-mediated LC-MS method for capping efficiency 
• RP-LC-MS/MS for quantification of modified nucleosides in mRNA 
• ELISA methods for determination of residual protein content, dsRNA and expression of the target protein 
• fluorescence-based assay for RNA encapsulation efficiency 
• additional mRNA and lipid extraction methods to support drug testing

To advance this draft guideline, the USP is seeking feedback on the methods described from mRNA vaccine suppliers and manufacturers, contract manufacturers, drug testing agencies, regulatory authorities, and QA/QC specialists from industry, academia, and government. Recommendations for additional information to support the understanding of mRNA quality, submission of alternative analytical methods and supporting documents (e.g. validation documents) are also encouraged. The deadline for submissions is 25 July 2023.

The draft guideline and further information for your comments and/or supporting documents can be found at "Analytical Procedures form RNA Vaccine Quality (Draft Guidelines) - 2nd Edition".