Shire shareholders will own about half of the combined group after the deal, which will be the biggest in the sector since 2000 if approved by shareholders.
For the deal between Takeda and Shire to proceed, 75% of Shire's voting shareholders must support the transaction. Shares in the company will be listed on the Tokyo Stock Exchange and the Local Japanese Stock Exchanges, with Takeda also set to apply for its American Depository Shares to be listed on the NYSE. In response, the Irish firm announced on April 25 that it had told Takeda that Shire's board was willing to recommend the offer to its shareholders. Once complete, the merged firm will leapfrog AstraZeneca and Eli Lilly to become one of the largest pharmaceutical companies by sales. Having Shire also will increase Takeda's focus on gene-oriented treatments rather than traditional chemical compounds. Takeda had pitched a potential tie-up as complementary to its core therapeutic areas of oncology, gastrointestinal disease, and neuroscience.
In particular, Shire would give Takeda access to research and development in fields the Japanese firm has long sought, including digestive systems, mental illness and rare diseases. The company expects $1.4-billion in overall savings by the third year.
Takeda, which has seen its market value slide to US$34 billion since announcing its interest, is taking over a much bigger rival.More news: 23 killed as coal mines collapse in Pak
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Tokyo-listed Takeda's shares, however, climbed nearly four per cent to ¥4,638 (£31.50).
"Together, we will be a leader in providing targeted treatments in gastroenterology, neuroscience, oncology, rare diseases and plasma-derived therapies", he said.
In a separate statement today, Takeda said it will continue to focus on growing its oncology portfolio, which along with its hematology holdings expanded past year when Takeda acquired Ariad Pharmaceuticals for $5.2 billion.
Four previous approaches from Takeda had been rebuffed.
Takeda said the integrated company will be headquartered in Japan, listed in both Tokyo and NY, will expand its R&D presence in the Boston, US, area, and have major regional locations in Japan, Singapore, Switzerland and the US.