Pharmaceutical giant Shire is raising $2.4 billion (£1.7 billion) by selling its cancer treatment unit to France's Servier.
The sale comes just weeks after Japan's Takeda Pharmaceutical said it was considering a takeover bid for Shire.
Shire says the sale of the oncology business was initiated in December and is unrelated to the possibility of a takeover bid.
The company said it may also sell other assets that it judges as not central to its business.
"While the oncology business has delivered high growth and profitability, we have concluded that it is not core to Shire's longer-term strategy," said Shire's chief executive Flemming Ornskov.
"We will continue to evaluate our portfolio for opportunities to unlock further value and sharpen our focus on rare disease leadership with selective disposals of non-strategic assets," he added.
Shire specialises in developing treatments for rare diseases. The company was founded in the UK and still has a large base in Basingstoke, but relocated its corporate headquarters to Dublin in 2008.
Under UK rules governing takeovers, Takeda has until 25 April to launch a bid for Shire.
It has been reported that Takeda's boss is meeting some of Shire's biggest shareholders this week to discuss a possible takeover offer.
Investors will be keen to know how Takeda intends to fund the takeover of Shire which has a bigger market value.
Not-for-profit
France's Servier is controlled by a not-for-profit foundation and invests all of its profits into drug development.
It also allocates a quarter of its sales to research and development.
Its group president, Olivier Laureau, said the deal will help its ambition to become a leading organisation in cancer treatments and also gives it access to the US market, reports BBC.
