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DNA Vaccine Technology by Magda Marquet


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DNA Vaccine Technology by Magda Marquet

  1. 1. V a c c i n e s section oneDNA Vaccine TechnologyBiotechnology’s Brave New Worldby Magda MarquetP icture rows and rows of for a production run down to weeks. chicken eggs incubating not to Last year, the industry managed to hatch chickens, but to produce produce H1N1 flu vaccines in about vaccines. With the exception of 30–40 weeks, but that wasn’t gooda few products on the market now, enough. DNA vaccines take four to sixmost vaccines are still made using this weeks to go from gene sequence to vial.50-year-old technology. Using chicken The production process is safer, as areeggs to produce vaccines takes about the products themselves. We’ve closely research started. A 1993 paperhalf a year to complete and requires examined the potential issue of DNA reported on a collaboration betweenon average one to two eggs to make a integration into the chromosomes of Merck and Vical showing that thesingle vaccine dose. It is inefficient, recipients. In many safety studies, we’ve technology worked quite efficiently inlabor intensive, time consuming, and never found that to happen. The an influenza model (2). In 1994,subject to contamination. The latter product doesn’t integrate, and it gets David Weiner at University ofmay be the most important problem. In removed from a person’s body over time. Pennsylvania filed the first IND for aaddition to the vaccine you want, DNA vaccine technology is also DNA vaccine. And then my group atcontaminants (including other viruses) less expensive than that for traditional Vical developed the first processes tocan get into the product stream. vaccines. It uses bacterial fermentors make pharmaceutical-grade DNA (3). But there may be a way to that can be used for other processes, When I entered the field, all themodernize our vaccine technology. and DNA vaccines can be made using methods used for DNA productionRather than producing a virus or a very simple techniques — even more were based on the use of ethidium-protein to inject into an organism, we straightforward than the recombinant bromide double-cesium purification,can produce a sequence of DNA that DNA technologies used to express resulting in DNA that could not behas been genetically engineered to protein subunits. injected into humans. So we needed aexpress proteins from a specific However, all the market successes process that could be scaled up forpathogen when introduced into an we’ve had so far have been in animals: clinical (and eventually commercial)organism. The idea is that once the horses, salmon, pigs, and dogs (Table vaccine manufacturing. Although noworganism’s cells have made the proteins 1). The dog melanoma vaccine, in it’s pretty obvious to purify kilogramfrom that DNA sequence, the immune particular, has made a big difference in quantities of DNA, fifteen years ago itsystem will recognize them as foreign curing a problem that was previously required a change of mind set forand launch a response against them. very difficult to treat. This validates biochemists who were used to purifying I’ve been working in DNA vaccines the DNA vaccine technology, and it protein and getting rid of DNA.for two decades. At first, as strong also shows that we’re almost ready for The early 1990s generated a lot ofbelievers in a powerful technology, we human vaccines. It demonstrates that excitement about DNA vaccines,thought we would have approval in this technology is very cost efficient followed by some clinicalhumans in less than five years — but because costs in veterinary applications disappointments — except in animals,that didn’t happen. Yet this is still a are necessarily lower than in human where the technology has worked veryfield that I believe will revolutionize the medicine. well. Since then, we’ve seenworld of vaccines. We still have many refinement and optimization of DNAchallenges to overcome, but it’s clear hisTorical oVerView vaccine expression, potency, andthat we have made significant progress. In 1990, by pure serendipity Wolf and immunogenicity. Novel formulations Felgner discovered in a controlled and adjuvants are providing muchTechnological success experiment that injecting DNA in better protection. There’s beenWhy use DNA vaccines? First, they are mice produced an immune response optimization at the genetic level: e.g.,fast: decreasing the traditional months (1). That got the field of DNA vaccine codon optimization to increase T-cell2 BioProcess International 9(8)s S eptember 2011 Supplement
  2. 2. Table 1: Four veterinary vaccines have been licensed, which validates the technology.response. And heterologous prime- Target Company/Sponsor Year Approved Speciesboost vaccination is making West Nile virus Centers for Disease Control and 2005 Horsesignificant inroads (4). Harriet Fort Dodge LaboratoriesRobinson’s group at Emory University Infectious heamatopoietic Novartis 2005 Salmonin Atlanta, GA, has achieved good necrosis virusresults in primates using DNA for Growth-hormone–releasing VGX Animal Health 2007 Swinepriming and recombinant modified hormonevaccinia Ankara (MVA) virus. Melanoma Merial/MSK 2007 DogManufacTuring Progress Figure 1: Fermentation optimization (plasmid yield improvement)Meanwhile, diligent work in 1,200manufacturing technologies hasaddressed yield and stability issues. 1,067.00These methods are scaling up 1,000successfully to at least 1,000 L or more.And a 1,000-L process can yield 866.40 Plasmid DNA (mg/L)millions of vaccine doses, which allows 800for commercial production in a relativelysmall plant. Disposable bioreactors do 652.00not work for DNA vaccine production 600because of oxygen-transfer limitations. Original Batch ProcessBut single-use technologies do play a 381.23significant role in downstream 400 374.92processing to reduce cleaning validationwork, improve manufacturing 186.15efficiencies, and lower overall costs. 200 119.72 Major progress in formulation and 75.79 54.00 62.56 85.50 61.90 82.33lyophilization technologies is making 13.54 0DNA vaccines more shelf stable. The Fed-Batch Development Experimentscold chain is a major issue for allvaccines, especially those sent to 2 Ulmer, et al. Heterologous Protectiondeveloping countries. Not everyone a BraVe new world Against Influenza By Injection of DNAhas the necessary refrigeration or Are DNA vaccines ready for prime Encoding a Viral Protein. Science 259, 1993.freezing equipment to store sensitive time (5)? It’s taken nearly 20 years, 3 Horn, Marquet, et al. Cancer Geneliquid formulations. and development is ongoing. Things Therapy Using Plasmid DNA: Purification of Case Study: Figure 1 shows the didn’t work the way we initially DNA for Human Clinical Trials. Hum. Genekinds of product yields we’ve had over imagined they would, but that’s Ther. 6, 1995.the years at Althea. It begins with similar to the story of monoclonal 4 Robinson HL. Prime Boost Vaccines Power Up in People. Nat. Med. 9, 2003: 642–643.something we thought was pretty antibodies (MAbs). After 20 years, by 5 Kutzler MA, Weiner DB. DNAgood at the time! Now we regularly the time many investors didn’t believe Vaccines: Ready for Prime Time? Nat. Rev. Genetics 9, 2008: 776–788. csee g/L product titers. Human-vaccine in MAbs anymore, the technologylots we’ve produced range mainly from finally worked — and that changedpreclinical to phase 2 scale. We’ve the pharmaceutical industry. I see this Magda Marquet, PhD, is cofounder andworked with clients from Europe, the coming for DNA vaccines as well. cochair of the board of directors for AltheaUnited States, and the Asia–Pacific Major progress has been made not technologies, inc., 11040 Roselle street, sanregion, to produce preclinical, phase 1, only in basic science and product Diego, cA 92121; 1-858-882-0123, fax 1-858-and phase 2 products. development, but also in delivery and 882-0133; Our process development team has manufacturing. Collaboration amongprogressively been able to increase industry, academic laboratories, and this article is adapted from a presentationmanufacturing yields through a range governments has facilitated much of given at Interphex in new York, nY, Marchof fermentors from the 30-L scale to that progress. Clinical trials are 2011 in a lunchtime session moderated bythe 100-L scale and now at the 1,000- ongoing to assess expression, potency, BPi’s editor in chief, s. Anne Montgomery.L level. We’re still working in the and immunogenicity. Once we get oneclinic to make sure that we have the success, then many others will follow, To order reprints of this article, contactright human-vaccine product before and it will be a revolution. Rhonda Brown ( can go to market. But in terms of 1-800-382-0808. Download a low-resolutionmanufacturing, we’re ready. That’s not references PDF online at limiting step. 1 Wolf, Felgner, et al. Direct Gene Transfer into Mouse Muscle In Vivo. Science 247, 1990.Supplement S eptember 2011 9(8)s BioProcess International 3