NEW YORK/LONDON (Reuters) - London-listed rare disease drug maker Shire Plc (SHP.L) said on Thursday it had rejected a $63 billion cash-and-stock acquisition offer by Japan’s Takeda Pharmaceutical Co (4502.T), even as their talks continued, while Allergan Plc (AGN.N) dropped its rival bid.

FILE PHOTO: Takeda Pharmaceutical's signboard is seen on its headquarters building in Tokyo, Japan January 30, 2018. REUTERS/Kim Kyung-Hoon/File Photo

Botox-maker Allergan confirmed on Thursday it was considering an offer for Shire after Reuters reported on its interest, sending its shares down 7 percent.

Later on Thursday, Allergan CEO Brent Saunders decided to drop his pursuit of Shire after receiving pushback from some of his shareholders, who were concerned about the company overstretching its resources, according to people familiar with the matter, who asked not be identified discussing confidential talks.

Dublin-based Allergan, which has a market capitalization of $52 billion, had a debt pile of $30 billion as of the end of December, the legacy of a string of acquisitions.

Allergan’s exploration of a bid for Shire was part of its wider strategic review, Allergan said in a statement. This review is currently unlikely to lead either to a major acquisition or a breakup of the company, one of the sources said.

Reuters also first reported on Thursday that Takeda had made a cash-and-stock offer of 46.50 pounds ($66.20) a share for Shire. This prompted both companies to confirm the move and announce that Shire had rejected it, although their negotiations are continuing.

Buying would be the largest ever overseas acquisition by a Japanese company and propel Takeda, led by Frenchman Christophe Weber, into the top ranks of global drugmakers.

It would be Weber’s boldest move by far, significantly boosting Takeda’s position in rare

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