The Food and Drug Administration Tuesday approved a new treatment developed by Protalix Bio Therapeutics Inc. (PLX, PLX.TV) for children and adults with a type of Gaucher disease, a rare genetic disorder.

The treatment, taliglucerase alfa, will be sold in the U.S. under the brand name Elelyso by Pfizer Inc. (PFE).

Pfizer also will sell the drug in most places outside the U.S. The drug, which is the first plant-derived cell-based enzyme replacement, replaces an enzyme called glucocerebrosidase in people with type 1 Gaucher disease. Elelyso is produced using genetically engineered carrot cells.

People with Gaucher disease lack glucocerebrosidase, which causes an accumulation of a fatty substance inside cells. The fatty accumulation can lead to enlargement and malfunctioning of the liver, spleen, bone marrow and occasionally, the lung, kidney, and intestine. About 6,000 people in the U.S. have type 1 Gaucher disease according to FDA.

Pfizer and Protalix have already been making Elelyso available to some Gaucher disease patients as part of an early access program because of manufacturing issues at Genzyme, a unit of Sanofi (SNY) which makes another glucocerebrosidase-enzyme replacement product, Cerezyme. Earlier this year Genzyme said the manufacturing problems had been fixed and that the company is able to make enough of the product to supply current patients in the U.S.

Shire PLC (SHPGY, SHP.LN) which also makes a Gaucher disease treatment, Vpriv, has said inventories of the product will be "below target levels" until the FDA signs off on a second manufacturing plant in the U.S. However, the company also said it has the capacity to meet anticipated demand for Vpriv.

Officials from Pfizer and Protalix said the companies have already built enough inventory of Elelyso to supply to patients for at least 24 months.

Elelyso is an infusion that is administered by health-care professionals every other week.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com