Eisai Co. Ltd. (4523.TO) said Thursday it aims to overcome an expected drop in revenue from the expiry of the U.S. patent of its best-selling prescription drug by launching new products and expanding existing operations.

Company president Haruo Naito said the expiry in November this year of the U.S. patent on its Aricept Alzheimer's drug is expected to cause a Y105 billion decline in sales by the fiscal year ending March 2013.

But Naito said his company can offset the drop with a Y65 billion increase in revenue in the U.S. through introducing new drugs and boosting sales of existing drugs, as well as a Y20 billion growth in domestic sales and another Y20 billion boost from its growth in China by March 2013.

Among major products planned for launch in the new fiscal year from April, Eisai expects its breast cancer drug Eribulin to generate peak-level annual sales of $1 billion.

Eisai also expects its sepsis treatment Eritoran to bring in $1 billion in peak annual sales.

As for its business in China, the company aims in two years to double its forecasted sales of Y20 billion for the next fiscal year ending March 2011, Naito said.

Eisai also aims to lift its return on equity to around 15% in the year to March 2012, from 9.7% forecast for the current fiscal year, and earnings per share to Y228 from the current Y141.4 over the same period, Naito said.

-By Kazuhiro Shimamura, Dow Jones Newswires; 813-6269-2790; kazuhiro.shimamura@dowjones.com