Pfizer Inc. will spend up to $115 million for rights to an Israeli biotech company's experimental drug and its promising technology for making that drug and others in carrot cells. The world's biggest drugmaker said Tuesday its deal with Protalix BioTherapeutics Inc. involves a "groundbreaking" technology - the first to use plant cells to make protein-based drugs - that would be safer than the animal cells now used by biotech companies. The deal also gives Pfizer worldwide rights, except in Israel, to sell a genetically engineered drug called taliglucerase alfa to treat a rare inherited condition called Gaucher's disease. Caused by deficiency of a particular enzyme, it damages the liver and bone marrow, sometimes leading to death. "Either one, on their own, would be great," said David Simmons, head of Pfizer's established-products business, referring to the technology and the drug covered by the deal. Dr. David Aviezer, chief executive of Protalix, said his company expects by month's end to complete its submission of data to the US Food and Drug Administration, from which it is seeking approval to sell taliglucerase alfa. The drug produces the enzyme - a type of protein that triggers a biochemical reaction - that's deficient in Gaucher's patients. Protalix already is testing additional possible uses, including other rare, enzyme-related diseases and more-common rheumatoid arthritis, for making drugs with its technology, which Aviezer said is safer than standard biotech manufacturing. Today, biotech companies manufacture drugs in bioreactors - enclosed, sterile vats containing special nutrients and, usually, Chinese hamster ovary cells. Human genes spliced into those ovary cells instruct them to clone, or copy over and over, a specific protein, the active drug ingredient. Occasionally, Aviezer said, those cells have become contaminated by viruses, which could harm patients getting drugs made from them. "The minute you use a different cell line, such as a plant cell line," he said, "you create a biologic firewall. You totally avoid any risk of cross contamination... affecting the patient." Protalix will receive $60 million upfront for licensing rights to the Gaucher's treatment. Taliglucerase alfa has been designated an orphan drug by the Food and Drug Administration. Orphan-drug status is given to drugs aimed at rare conditions or conditions that have a lack of treatments on the market. Incentives include seven years of market exclusivity following FDA approval, assistance in clinical trial design, a reduction in user fees and tax credits. Protalix is eligible to receive additional regulatory milestone payments of up to $55m. Pfizer will pay for 60 percent of the expenses for the development and sales of the drug, while receiving 60% of revenue from sales.