Molecular farming in plants: The long road to the market

Abstract

Recombinant proteins can be produced on a commercial scale using a diverse array of host systems based on microbes, animals, and plants. Commercially established processes have resolved to a small number of standard platforms, including the bacterium Escherichia coli, the yeasts Saccharomyces cerevisiae and Pichia pastoris, and certain well-characterized insect and mammalian cell lines. In contrast, many different plant-based systems have been developed and only in the last few years have standardized platforms begun to emerge. The diversity of plant-based platforms has been advantageous to molecular farming by helping to overcome technical issues, but the failure to focus on specific platforms has made the transition from experimental development to a viable commercial process a long and difficult one. As well as the technical and economic principles required to develop a viable manufacturing processes, plants have also been held back by the lack of a harmonized regulatory system for plant-derived pharmaceutical products, such that much of the early commercial development of molecular farming focused on non-pharmaceutical proteins. Despite these hurdles, pharmaceutical molecular farming is now firmly established in the market, and we are witnessing the dawn of a new age in which plants are regarded as competitive platforms for the commercial production of diverse recombinant pharmaceutical protein products.