Biotech drug production techniques based on plants, which may prove to be faster, higher yielding and cheaper than current methods using mammalian cells, haven’t caught on with the biggest pharmaceutical companies.

The leading players in so-called “plantibodies” include San Diego’s Mapp Pharmaceutical, which garnered global attention for an experimental Ebola drug given to two American medical workers, as well as companies like Germany’s Icon Genetics, Canada’s PlantForm Corp, and Delaware-based IBio Inc. All of the privately-held companies are working to produce antibodies, protein drugs and vaccines in fast-growing plants.

These companies hope the lower cost of plant-based production — in some cases as little as one-tenth the expense of conventional antibody manufacture — will eventually capture the attention of larger drugmakers. Big pharmaceutical makers have yet to embrace the technique after spending hundreds of millions of dollars on their current manufacturing lines.