Eisai's acid reflux drug gets US priority review

TOKYO, March 2 (Reuters) - U.S. regulators have granted priority review for a new application of Eisai Co Ltd's (4523.T) Aciphex acid reflux drug, Japan's fourth-largest drug maker said.

A priority review means the Food and Drug Administration (FDA) will likely decide within six months whether to approve the treatment, rather than the usual 10-month review period.

Aciphex, known chemically as rabeprazole sodium, belongs to a class of drugs known as proton pump inhibitors designed to suppress production of stomach acid that can burn and damage the esophagus, a condition known as gastroesophageal reflux disease.

Eisai said on Saturday that the FDA had accepted a supplemental New Drug Application (NDA) for Aciphex for the short-term treatment of gastroesophageal reflux disease in patients of age 12-16.

It said the FDA has indicated it would grant the new application priority review status.

Eisai derives nearly half of its U.S. drug sales from Aciphex and it is its second-biggest selling drug after Aricept, which is used to treat Alzheimer's disease.

It competes with other popular medicines such as Nexium and Prilosec from AstraZeneca (AZN.L), Wyeth's (WYE.N) Protonix and Prevacid from TAP Pharmaceuticals, a joint venture of Abbott Laboratories (ABT.N) and Takeda Pharmaceutical Co (4502.T).

A unit of Johnson & Johnson (JNJ.N) (JNJ.N) co-markets Aciphex with Eisai in the United States. (Reporting by Nathan Layne; Editing by Erica Billingham)