UPDATE 2-Protalix Gaucher drug successful in clinical trial

* Protalix Gaucher drug successful in trial

* Company says could be approved in mid-2010

* Drug would compete with Genzyme's Cerezyme

BOSTON, Oct 15 - The Israeli biotechnology company Protalix Biotherapeutics Inc said on Thursday that its experimental drug to treat Gaucher disease, a rare genetic disorder, was successful in a late-stage clinical trial.

If approved, the drug, Uplyso, would compete with Genzyme Corp's biggest-selling drug, Cerezyme.

Protalix said it expects to complete its marketing application with the U.S. Food and Drug Administration by the end of this year, and could have the drug on the market by mid-2010.

The company said it will have enough capacity, on approval, to supply 1,000 patients. Gaucher is a rare disease that affects about 5,000 people around the world. Sales of Cerezyme were $1.2 billion last year.

Protalix said it is expanding its manufacturing capacity and will have enough product to supply 2,500 patients by the end of next year.

Patients with Gaucher are deficient in an enzyme that breaks down a certain type of fat molecule, leading to potentially deadly organ damage. To date, Cerezyme has been the world's dominant supplier.

But a viral contamination at Genzyme's manufacturing plant in Boston earlier this year has caused shortages of Cerezyme, which prompted the U.S. Food and Drug Administration to allow Protalix and British drugmaker Shire Plc to supply patients with their own drugs before they have received official approval.

Protalix, which makes its product using genetically engineered carrot cells, said a late-stage, Phase III trial of Uplyso, which is known generically as taliglucerase alfa and was previously referred to as prGCD, reduced spleen volume by a statistically significant amount after nine months.

The differences were experienced by patients who took a higher dose of 60 units per kilogram, as well as patients who took a lower dose of 30 units per kilogram.

Shares of Protalix closed at $8.88 Wednesday on American Stock Exchange.