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How to deploy mRNA vaccine production and facility design?
We have also seen that people are becoming more and more aware of some relatively complex but significant technologies. Including various vaccine types and subtypes, ranging from cell secretions to AAV vector vaccines, to viral antigen mRNA lipid nanoparticles.
Although traditional platforms are still in use, innovative vaccine delivery systems are emerging, and now include fully synthesized antigen structures, subviral particles, and various chimeric vectors. The antigen production platform uses a variety of methods, such as animal tissue, cell-free expression, plant expression, cell culture, and direct chemical synthesis.
Even if the discussion is limited to cell-based manufacturing, multiple platforms will emerge, from E. coli to yeast to fungi to animal cells. Operating methods range from single-use (SU) to fed-batch microcarriers to fixed-bed continuous systems. In addition, since components such as filters and resins will continue to change and evolve over time, traditional production processes need to keep up.
In addition, we are seeing breakthroughs in many different types of cell products, such as antigen proteins, attenuated or subsequently inactivated viruses, virus-like particles (VLP), vectors or delivery packages, such as extracellular vesicles (EV), and Bacteria or bacterial vector vaccines.
What is an mRNA vaccine?
The mRNA vaccine is a new type of vaccine designed to prevent infectious and chronic diseases. Many classic vaccines introduce isolated natural or recombinant antigen assemblies into our body to trigger an immune response. But mRNA vaccines program our cells to make a protein—just a protein—and then use the protein to trigger an immune response.
For example, the COVID-19 mRNA vaccine uses mRNA to encode multiple immunogenic epitopes of a harmless COVID-19 viral component called a spike protein. They deliver mRNA to our cells in carriers, such as polymers or lipid-based nanoparticles.
After the particles deliver the mRNA, our cells produce spike protein antigens and then decompose the mRNA. The cell then displays the protein on its surface, and our immune system recognizes it as a foreign object and builds an immune response against it.
How is mRNA vaccine production produced?
mRNA API production
The nucleotide portion of the mRNA vaccine can be prepared in four different ways. it can:
1) Chemical production, that is, synthesis in a chemical reactor;
2) Through in vitro transcription, using linearized DNA templates obtained from bacterial plasmids;
3) Using PCR amplified DNA template;
4) Now, a commercially available double-stranded DNA fragment is used as a template. For DNA template-based in vitro transcription (IVT) production, ribonucleotides and T7, T3 or Sp6 phage DNA-dependent RNA polymerase are used to provide all transcription factors (start, extend or stop). We will focus here on this method based on plasmid templates.
Because the mRNA vaccine is a completely different type of product, the current factory only has a small number of small-scale production kits. Unlike facilities that produce egg-based vaccines or even monoclonal antibodies, a fully commercial-scale mRNA vaccine production base usually contains 3 to 5 production kits, one of which supports a 5-50L production fermenter to produce plasmids (DNA templates).
Typically, frozen cells from a central cell bank are thawed and expanded in shake flasks used for inoculation of production fermenters. The fermentor is filled with culture medium and inoculated with the contents of the flask. Then the fermentation process takes 1-2 days. The culture is then cooled at the end of the fermentation, and the harvested culture is centrifuged to separate the cell mass (including the plasmid template of the mRNA) from the spent medium. After cell lysis, the harvest can be clarified by, for example, depth filtration. The DNA plasmid can be purified from the clarified lysate by column chromatography, enzymatic digestion, a series of ultrafiltration/diafiltration filtration and final sterile filtration steps.
MRNA production from plasmids
Then the purified plasmid together with the in vitro transcription (IVT) reagents and enzymes from the buffer preparation area are transferred to the reaction vessel, and the reaction is completed within a few hours. The plasmid can then be removed by incubating and digesting with DNase within a few minutes. The quenched IVT product is concentrated, purified, and conditioned by chromatography and filtration. Finally, the mRNA is processed in a capping reaction within a few hours, and then purified, buffered, diluted, and sterile filtered.
Pharmaceutical preparations and sub-packaging
Prepare delivery systems, such as polymer or lipid-based nanoparticles (LNP), and then encapsulate purified mRNA in them using methods specific to different manufacturers. The resulting mRNA/delivery nanoparticle assembly undergoes concentration, buffer exchange, and sterile filtration. Then it is finally evaluated and packaged in this order into bags/bottles as APIs. The bulk drug is usually frozen and stored before it is finally formed (although not applicable to some processes), and in some cases it needs to be lyophilized later.
Today, factories are providing a larger digital or “4.0” production environment to achieve high throughput and robust manufacturing processes for various products. The enterprise control system can easily realize the flexibility of technology transfer and manufacturing in a highly automated processing environment. In fact, digital technology is now integrated into the entire modern factory, including enterprise resource planning systems with electronic production records, process control systems, data history records, and laboratory information management systems. Such a digital platform simplifies product manufacturing, testing, and release. They also support powerful data management to support process development, characterization, and transmission.
We have seen a wider range of digital system integration in all aspects of the facility, including elements of procurement, process, quality, and distribution systems, thereby providing a more integrated manufacturing and supply chain. This will result in a cloud-based automated system that manages the planning and execution of the vaccine pipeline, from design and scale-up, to manufacturing and distribution, to post-market supervision of the product.
The new design provides more added value while requiring the production process to maintain GMP conditions, facilities and control requirements. They are the result of many technological advancements, including those in building materials, work processes, equipment, utilities, and air conditioning. One-off, closed, continuous and modular process design is changing the style of space allocation and classification.
The rapid delivery of flexible and adaptable facilities is currently provided by qualified suppliers supported by advanced aseptic processing solutions, facility design and construction. These suppliers are providing compliant materials, space allocation, workflow and equipment design for research and manufacturing. It is now necessary to understand high-throughput and straight-through manufacturing methods with product and process flexibility, and expect to be able to establish flexible manufacturing processes and spaces to quickly switch between existing product activities or newly developed product candidates.
Modularity and modular prefabricated facility design has become a regular consideration for many projects. They can reduce floor space, shorten time to market, reduce service requirements and operating expenses. Multi-product, process design and process sequence construction and operation costs are lower, and it can also provide higher flexibility and higher environmental sustainability. Another trend is the nesting of classification spaces. Prefabricated clean facilities can be installed in an unclassified (gray space) environment, and by adding a closed system to them, they can themselves be classified and operated with reduced facilities.
Even traditional warehouse design and operations are changing. Automated storage and retrieval systems can greatly improve storage capacity and picking efficiency. The new warehouse design, software and automatic retrieval equipment can increase productivity, restore floor space and improve picking accuracy through absolutely ergonomic performance.
mRNA vaccine API facility
Many aspects of mRNA vaccine development and production are consistent with many other regulated biological products—for example, most services, supplies, and QC technology. But some elements can be very different. For mRNA vaccines, physical production in relatively small-scale fermentors/reactors distinguishes them from larger-capacity biological manufacturing.
From a regulatory point of view, due to the new components of vaccines, it is even difficult to know which department or department of the agency started filing. For example, the FDA has two basic departments to register biological and pharmaceutical compounds, namely CBER (Center for Evaluation and Research of Biological Products) and CDER (Center for Evaluation and Research of Drugs). The differences need to be studied in detail, because they are not necessarily intuitive in terms. Facts have proved that the current mRNA vaccine is not regarded as Advanced Therapy Medicinal Products (ATMP), and in the United States, a marketing application (BLA) is being submitted under the auspices of CBER.
Regarding facilities, the FDA Industry Guidelines for Vaccine Development and Approval for the Prevention of COVID-19 (FDA-2020-D-1137) provides quite standard guidance for the facility itself, such as operations should be fully designed to prevent contamination; facilities and equipment must be verified to be clean and Processes such as maintenance, sterile filtration and sterile activities; HVAC systems (Heating, Ventilation, Air-conditioning and Cooling) must provide adequate control; and manufacturing equipment should be qualified.
It clearly recommends communicating with CBER’s Office of Compliance and Biological Product Quality to discuss inspections, and inspections are usually conducted after acceptance of the BLA document (21 CFR 601.20). However, it noted that during the COVID-19 public health emergency, the FDA is using other tools to determine whether on-site inspections are required.
The mRNA vaccine bulk drug production facility will support three basic activities, following the outline of the production activities described above. They are:
1) Ferment the transfected bacteria (such as Escherichia coli) to produce DNA plasmids, and then purify the DNA plasmids;
2) Produce and purify mRNA bulk drugs from this plasmid, and purify (and freeze) them;
3) Production of polymer or lipid-based nanoparticles combined with mRNA drug products/carriers. The manufacturing plant will directly support all of these, of course, also requires standard areas such as buffer/medium preparation, weighing/distribution, service, etc.
Usually, equipment contains separate manufacturing kits:
For example, dedicated to:
1) buffer and medium preparation,
2) mRNA production,
3) nanoparticle formulation,
4) mRNA/nanoparticle assembly
5) final API product formulation /Sterilization/packaging.
Some sponsors will operate steps 3 and 4 in the same area. Depending on the scale, the buffer can be dispensed from the buffer preparation chamber in one of two ways: it can be directly from the buffer preparation chamber through a pipe (fixed or flexible disposable pipe) into the production kit, or it can be carried by carrying bags To the device and transmitted via a flexible connection. There are usually practical panels available, including instrument and process air, oxygen and nitrogen, and solvent water-based waste tank stations.
This is an exciting time for vaccine entity sponsors, material suppliers and facility designers. CureVac collaborated with Elon Musk to create a “mobile molecular printer”, illustrating a series of possibilities that can even be used for mRNA vaccine process and kit design. Although the details of the size and requirements of these “mRNA microfactories” have not been disclosed, we do know that they are described as highly automated and designed to be shipped to remote areas. Compared to current mRNA vaccine facilities, this may indicate unique service support and reduced footprint/personnel requirements.
(source:internet, reference only)