Japanese authorities have approved Shionogi & Co. Ltd.'s single-dose influenza drug Xofluza, the company said Friday, Feb. 23.

The treatment may not be available in Japan prior to May as the national insurer has not yet set a price, The Wall Street Journal reported, citing a Shionogi spokesman.

Later this year, Shionogi intends to file for approval for Xofluza in the U.S. and a decision is not expected before 2019, according to the report.

Japan's Ministry of Health, Labor, and Welfare designated the drug, then known as S-033188, for priority review in October 2015. In October of last year, Shionogi said it had filed for approval to manufacture and sell the treatment.

Xofluza requires a single oral dose. By comparison, patients take Roche AG's  (RHHBY) Tamiflu for five days.

In February 2016, Osaka-based Shionogi signed a license and collaboration pact with Roche for the development and commercialization of S-033188. As part of the deal, Shionogi agreed to develop the treatment in tandem with Roche globally, except Japan and Taiwan, which Shionogi retained exclusively.

Roche's American depository receipts ended Friday's trading session at $29.75, down 0.3%.

Roche gained the right to commercialize the drug worldwide except Japan and Taiwan, with Shionogi retaining certain co-promotion rights in the U.S. Shionogi will be entitled to receive royalties on sales of S-03318. 

In the U.S., flu activity remained elevated during the week ended Feb. 17, according to the Centers for Disease Control and Prevention. There were 13 influenza-associated pediatric deaths reported during the period. A cumulative rate of 74.5 confirmed influenza-associated hospitalizations per 100,000 population was reported, CDC said.

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