Pharmaceutical company Shire PLC (SHP.LN) said late Monday the U.S. Food and Drug Administration asked it to seek permission to provide doctors with its experimental treatment for Gaucher disease because of a shortage of Genzyme Corp.'s (GENZ) Cerezyme.

Shire said it filed a treatment protocol for velaglucerase alfa, or vela, at the request of the U.S. Food and Drug Administration because of shortages of Cerezyme, an approved and marketed treatment, caused by manufacturing problems at a Genzyme plant.

If approved by the FDA, the treatment protocol would allow physicians to treat Gaucher disease patients with vela before it is approved for sale and commercially available. Shire said it would provide it initially free of charge.

Shire said it is currently working with the FDA to file a new drug application to get vela approved.

Panmure Gordon & Co. analyst Savvas Neophytou told clients in a research note Tuesday acceptance of the protocol by the FDA would let Shire access the $1.2 billion Gaucher disease market earlier than expected.

"Should the company be able to access this market in 2009, it could represent a good entry into this market because it had previously been assumed that Cerezyme was a very strong incumbent," Neophytou said.

He added if Shire can access the market while Genzyme is "on the floor" then it should be able to convert these initial sales into long-term business. But he added that would work best provided Cerezyme supply was constrained beyond August.

At 0826, shares in Shire were up 13 pence or 1.6% at 850.5 pence, outperforming a higher FTSE 100 index, up 0.3%.

Genzyme's Cerezyme is the only approved enzyme replacement therapy for treating Gaucher disease, an often severe and debilitating condition caused by an enzyme deficiency.

The Cambridge, Massachusetts biotechnology company discovered a virus in a "bioreactor" at a facility used to make Cerezyme last month, and shut down production. Current inventories wouldn't be enough to avoid shortages, Genzyme said.

The company said it expects production to resume later this month.

Monday, Israel's Protalix BioTherapeutics Inc. (PLX) said the FDA approached it about submitting a treatment protocol for its experimental drug to treat Gaucher disease, prGCD. It isn't yet approved for sale either, and a phase three trial is underway.

Protalix said the FDA asked it to consider submitting the protocol because of an expected shortage of Genzyme's Cerezyme.

Company Web site: www.shire.com

-By Jason Douglas, Dow Jones Newswires; 44-20-7842-9272; jason.douglas@dowjones.com