GlaxoSmithKline is to acquire its long-time partner Human Genome Sciences for about $3bn (£1.9bn), ending a three-month hostile pursuit of the US biotech company on friendly terms after sweetening its offer.
The deal comes after weekend talks in which Britain's biggest drugmaker agreed to raise its cash bid to $14.25 a share from $13 previously, which Human Genome had rejected as inadequate.
Reuters earlier reported that the two sides were near a deal. The acquisition will secure GSK full rights to a recently launched drug for lupus and other new medicines.
Biotechnology companies are in increasing demand as Big Pharma companies seek new products to replace older medicines that are going off patent in the biggest wave of drug patent expiries in history.
In addition to gaining 100 percent of Benlysta to treat lupus, a disease of the immune system, GSK also gets full ownership of experimental medicines for diabetes and heart disease that are in late-stage development.
Despite bumping its offer 10 per cent and paying a 99 per cent premium to the share price before its interest was made public, industry analysts said GSK had got a good deal - to the frustration of Human Genome investors hoping for a price in the high-teens per share.
"I'm disappointed with the deal because I think Benlysta is actually going to be a good drug," said Carol Werther, an analyst at Summer Street Research. "Glaxo wanted to get this on the cheap and they were able to do it in the absence of other bidders."
The boards of both companies have now approved the transaction, the two companies said on Monday. Their statement did not specify what future Human Genome Chief Executive Thomas Watkins had within GSK.
City A.M. Reporter