This week Pfizer revolutionized the entire world with the announcement of the preliminary (not final!) results of phase 3 clinical trials of its vaccine against SARS-CoV-2. This vaccine has a big peculiarity: it is an mRNA vaccine. And, although the potential of mRNA as a therapy against different diseases has been investigated for around 20 years, it is now that we are in front of what could be the first drug approved and used with this type of technology. But how does it work? How does this new technology affect the production process? And how does this advance influence the “rules of the game” within the pharmaceutical industry?
First of all, we are going to explain in a very simple way how this type of vaccine works. We will start by refreshing what many of us learned in school to understand how the vaccine works. The genetic information of living things is found in DNA, which is inside all cells. To “transform” this genetic information into actions, a copy of the DNA is needed. This copy is called messenger RNA or mRNA. With this mRNA, the cell will be able to interpret the genetic information to carry out an action (for example, to produce a protein). And how is this process integrated into a vaccine so that it ends up generating immunity against a virus?
mRNA vaccines to prevent Covid-19 introduce fragments of mRNA into our body. These fragments will reach our cells, which will be able to interpret the mRNA information. The information contained in this mRNA allows our cells to produce a protein found in the envelope of SARS-CoV-2 called protein S. Protein S by itself does not cause any damage, but is capable of acting as an antigen (substance that generates immunity in our body). The cells in our immune system will be able to recognize protein S and generate specific antibodies against it. This way, if the virus were to enter our body, we would already have specific antibodies that would recognize protein S present in the virus envelope. The antibodies would then neutralize and kill the virus before it could cause us illness.
Now we are going to focus on the process to produce this type of vaccine and how it changes compared to the usual production of other types of vaccines. One of the great challenges that often compromise the viability of a vaccine is to be able to produce the antigen in large quantities, since they are very complex compounds. One of the great advantages of mRNA vaccines is that they greatly facilitate the production process. This is because, instead of obtaining an antigen in the production line of a pharmaceutical plant, we give the information to our body (in the form of mRNA) so that it produces the antigen. If we think about it, it makes a lot of sense. Millions of years of evolution have made it possible for our cells to produce proteins with extremely high efficiency. So why produce proteins “artificially” outside our body when it can produce them if we give it the necessary information.
Thus, what must be produced in large quantities in the pharmaceutical plant is the mRNA fragment that contains the information to produce protein S. The process is much easier than the production of a recombinant compound. It basically consists on adding nucleotides (molecules of which RNA is composed), using DNA fragments as a reference and some enzymes that facilitate synthesis. Not using living organisms (as is the case in most types of vaccines) makes scale-up and purification much easier, and greatly reduces the number of contaminants. But the most interesting thing about mRNA vaccines is that the production time is greatly shortened. We must bear in mind that the production process of certain types of vaccines can take months or even years. In contrast, an mRNA vaccine can be ready in a few weeks or days. In addition, at a process level, the changes between mRNA vaccines aimed at preventing different diseases are minimal. This fact would enable the rapid adaptation of a production line in the event that it is required to produce another vaccine of the same type.
In several respects mRNA is still a premature technology and with much room for improvement. But its versatility, together with its large number of advantages, make it a very attractive technology. And not just for prevention treatments, such as vaccines. But also, for curative therapies (once the patient is already ill).
The establishment of this new technology will inevitably lead to changes in the production systems, to which both engineers and production plants will have to adapt.
If you are interested in learning more about processes involving mRNA therapies and how we can help you, contact us: firstname.lastname@example.org
- Pfizer and BioNTech Announce Vaccine Candidate Against COVID-19 Achieved Success in First Interim Analysis from Phase 3 Study. (2020, November 09). Retrieved November 11, 2020, from https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-vaccine-candidate-against
- Schlake, T., Thess, A., Fotin-Mleczek, M., & Kallen, K. J. (2012). Developing mRNA-vaccine technologies. RNA biology, 9(11), 1319–1330. https://doi.org/10.4161/rna.22269
- Jackson, N.A.C., Kester, K.E., Casimiro, D. et al. The promise of mRNA vaccines: a biotech and industrial perspective. npj Vaccines 5, 11 (2020). https://doi.org/10.1038/s41541-020-0159-
- Posted by Klinea
- On 12 November, 2020
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