The FDA has given Genzyme Corp. the green light to marketCerezyme _ the first recombinant "housekeeping" enzyme to bedeveloped and approved."This is very positive news for Genzyme," said Carol Werther, abiotech analyst with Cowen and Co. in Boston. "We were expecting theapproval this month and determined that it cound raise their earnings$1.45 to $1.50 a share."Cerezyme (recombinant glucocerebrosidase, GCR) is a replacementenzyme for treatment of Type I Gaucher's disease, a debilitating andsometimes fatal genetic disorder. Deficiencies of these enzymes, whichbreak down excess fats and other substances in the cells, are associatedwith several genetic disorders. Cerezyme will eventually replaceGenzyme's current Gaucher's drug, Ceredase (alglucerase forinjection) _ the only other effective treatment.Stephen Push, vice president for corporate communications, said theCambridge, Mass.-based company expects worldwide sales for bothproducts to reach $160 million this year, and to level off at around$200 million by the year 2000. Cerezyme has orphan drug status,entitling Genzyme to seven years of market exclusivity. "For practical purposes, the drugs are similar in structure and inclinical activity," Push said.Cerezyme was developed in less than three years to overcome supplyproblems with Ceredase, which received marketing approval in 1991.Ceredase is derived from human placentas. However, even thoughGenzyme was collecting virtually all placentas available, it still couldnot make enough product to supply more than 1,200 of the 5,000patients worldwide who required treatment.Although Genzyme plans to begin shipping Cerezyme within a month,it will still take some time before Cerezyme replaces Ceredase.Cerezyme is presently being manufactured in limited amounts at thecompany's small plant in Framingham, Mass. A larger plant is nowunder construction in Boston which should come on line in 1995. Atthat time, production of Ceredase will be phased out.Push said Genzyme hopes that large-scale production will help itachieve economies of scale that will bring down the price of Cerezyme.The company has taken a beating in Congress over the cost ofCeredase, which it estimated in 1994 at $150,000 a year per patient.Genzyme said this is about half the 1991 cost.Push said the company has not made a decision on how to price thenew drug, but noted that initially it will cost more to make Cerezymethan Ceredase.Until the supply of Cerezyme is adequate to meet the demand,Genzyme plans to ration its distribution. "We decided that a lotterysystem like that for Chiron's Betaseron did not make sense," Push said."So the drug will be given to people who make contributions tomedical knowledge. This includes people who participate in clinicaltrials of the product and who have not been treated with Ceredase.Since only 30 subjects participated in our Phase III trial, we want tocontinue to monitor its effectiveness and safety as new patients areenrolled. We also hope that this research will help us understand whatis the minimum effective dose. By reducing the dose, we could lowerthe cost of treatment."Cerezyme Advances Manufacturing TechniquesGenzyme says its new product "advances the state of the art inbiopharmaceutical manufacturing." The company predicts thattechniques developed to overcome problems in the manufacture of thedrug may aid in the production of other difficult-to-make proteins,including other housekeeping enzymes implicated in some 25 diseasescaused by genetic deficiencies. Genzyme already has a recombinantenzyme to treat Fabri disease in pre-clinical trials, according to Push.Genzyme said it had to overcome technical challenges to manufactureits recombinant enzyme. GCR could not be produced by bacterialfermentation, nor in large quantities. It is not naturally secreted anddoes not readily enter the patient's macrophages _ the cells thatprotect the tissues against disease organisms, in which it is needed.The solution the company found was to insert the gene for GCR intomammalian cells, together with other genes that increase expression ofthe GCR gene. Nutrients and other supplements were added to theculture medium to aid production and stabilize the protein. In this way,the cells produced unusually large amounts of GCR and expelled someof it into the medium. The enzyme was then purified and chemicallyremodeled so that it could enter the macrophages.Genzyme's (NASDAQ:GENZ) stock closed at $29.50, up 5 cents.News of the approval was not released until after 4 p.m.

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