Drug maker Daiichi Sankyo Co. said Monday it cut its sales forecast by 4.1 percent because of the stronger yen and pledged it will lower expenses to improve operating income.

Revenue will decline 3.9 percent to ¥930 billion in the year ending next March, missing a July forecast of ¥970 billion, Japan's second-biggest drug maker said.

First-half profit fell 29 percent to ¥37 billion, below the ¥40.8 billion average of three estimates compiled by Bloomberg.