Much of the funding for commercialization of plant expression technologies is originating from governments that realize that current vaccine technologies are inadequate. The U.S. government is the primary funder of new plant-based recombinant protein manufacturing technologies, particularly for influenza vaccine manufacture.
With conventional influenza vaccine manufacture primarily involving relatively slow and costly culture in vast quantities of chicken eggs, a method not capable of supplying the needs of major developed countries to immunize their populations, alternatives are being funded.
New manufacturing technologies for influenza and biodefense vaccines are needed to meet the rapid manufacture of vaccines. These technologies must be scalable to unprecedented levels, possibly as much as hundreds of millions of doses per week, to cover developed and developing countries’ needs in case of a serious pandemic threat. It is the need for rapid production that is driving the development of many plant expression systems.
Companies developing commercial-scale plant expression systems have certain advantages over conventional technologies. They have been able to design manufacturing systems from the ground up, allowing incorporation of the latest and most cost-effective technologies, avoiding many of the limitations and legacy aspects of fermentation-based technologies.
Plant-expressed versions of many other vaccines can be expected to be developed in the future. This will include vaccines for diseases currently lacking any vaccine or for which the costs restrict access to a relatively affluent few. For example, some plant expression systems, similar to insect cell-based systems, do a very good job of expressing viral subunits that self-assemble into virus-like particles.
Once plant-based influenza and other vaccines come online, this is likely to cause a shift in vaccine manufacture, as the current virtual monopolies of a few companies making most of the world’s vaccines are challenged. It is possible that new manufacturers may begin selling vaccines that may cost pennies to manufacture. Thus, more vaccines may become cheap commodity products.
Complementing this, new vaccine funding that comes through government and nongovernment organizations will require that vaccines be made available at unprecedented low costs. Plant expression technology is readily transferrable and is already on track for worldwide dissemination (licensing), unlike most recombinant technology that has largely been restricted to major developed countries.
Vaccines are currently a $20 billion/year industry, with many analysts projecting growth to $35 billion in five years. However, a few major pharma firms currently manufacture the great majority of the world’s vaccine supply, and this is one of the reasons governments and philanthropies are sponsoring alternative manufacturing systems.
Eventually, due to the need for low-cost vaccines, much of the world’s vaccine manufacturing capacity may be plant-based. New vaccines for diseases, for which none are currently available, will increasingly be manufactured in plant-based systems, with low manufacturing costs being irresistible compared to alternative manufacturing methods. Further, plant-based vaccines eliminate concerns about the risks associated with the use of animal-derived components in manufacture.
Eventually, greater proportions of vaccine manufacture may migrate to plant-based manufacture. This includes not just the current 12 commercial recombinant vaccines in either the U.S. or European markets, but more importantly recombinant versions of the ~85 nonrecombinant vaccines currently in these markets will likely be developed.
So far, the major international pharmaceutical and established biotechnology business model companies have largely avoided involvement in plant expression systems. This is expected to change, however, as these technologies mature and plant-expressed products enter the markets.