UPDATE 3-FDA speeds access to Protalix, Shire Gaucher drugs

* FDA asks Protalix to speed access to Gaucher drug

* FDA says Protalix drug meets expanded access criteria

* FDA action to offset likely shortages of Genzyme drug

* Protalix shares up 8 percent (Updates with comment from analyst, Protalix, Genzyme)

By Toni Clarke

BOSTON, July 6 (Reuters) - The U.S. Food and Drug Administration is moving to speed up access to experimental drugs for Gaucher disease to help offset likely shortages of Cerezyme, the top-selling drug made by Genzyme Corp (GENZ.O).

Biotechnology company Protalix BioTherapeutics Inc (PLX.A) and Shire Plc (SHP.L)(SHPGY.O) said on Monday they have been approached by the FDA to expand access to their experimental drugs for the rare but serious disorder.

Patients with Gaucher are deficient in an enzyme that breaks down a certain type of fat molecule. Fatty cells accumulate in different parts of the body, including the spleen, liver and bone marrow.

The shares of Protalix, which is based in Israel, rose 8.2 percent to close at $4.88 on the American Stock Exchange. Genzyme's shares were up 30 cents, or 0.6 percent, at $55.05. Shire stock rose 1.8 percent to end at $41.03.

Genzyme, which makes Cerezyme, the world's leading treatment for Gaucher disease, recently announced it would shut down its plant in Boston after a virus halted production of Cerezyme and Fabrazyme, its treatment for Fabry disease, another rare condition.

Protalix said the FDA asked the company to consider submitting a treatment protocol that would allow use of its treatment prGCD under an expanded access program. Under this program, a treatment protocol may be submitted for a drug that has not yet been approved, but is in development for a serious disease for which no other therapy is available.

The company is discussing the parameters of a proposed treatment protocol that would allow an increased number of patients with Gaucher disease to have access to prGCD, which is in late-stage development.

Shire said it has already filed a treatment protocol for its drug velaglucerase alfa. Both Shire and Protalix said they would provide their drugs free of charge.

David Aviezer, the chief executive of Protalix, expects approval of the treatment protocol within the next 60 days. He said the company is on track to file an application for full approval of the drug by the end of this year.

Some analysts said the FDA's action gives a good indication of how the agency views the drug.

"We view the FDA's request as clearly positive for Protalix, as it indicates FDA's comfort with prGCD's safety and efficacy data, and increases the likelihood of ultimate prGCD approval," said Brian Abrahams, an analyst at Oppenheimer & Co.