Please cross check with google.com for better results.
Here is the list of pharmaceutical companies in Japan:
1 Takeda Pharmaceutical Co.
2 Astellas Pharma Inc.
3 Daiichi Sankyo Co.
4 Eisai Co
5 Chugai Pharmaceutical Co.
6 Taisho Pharmaceutical Co.
7 Mitsubishi Pharma Corp.
8 Kyowa Hakko Kogyo Co.
9 Shionogi & Co.
10 Dainippon Sumitomo Pharma Co.
11 Tanabe Seiyaku Co.
12 Ono Pharmaceutical Co.
13 Meiji Seika Kaisha Ltd.
14 Asahi Kasei Corp.
15 Teijin Ltd.