Celgene to buy Juno Therapeutics for $9 billion

FDA approves breakthrough CAR-T therapy for leukemia

Biopharmaceutical company Celgene (CELG) is buying the remainder of Juno Therapeutics (JUNO) that it doesn't already own in a deal valued at about $9 billion, which will help it develop medicines for patients with incurable blood cancers.

Juno shareholders will receive $87 per share. The Seattle company's stock soared nearly 27 percent Monday less than three hours before the opening bell.

Celgene Corp., which is based in Summit, New Jersey, had owned almost 10 percent of Juno's outstanding stock.

The deal, which was approved by the boards of both companies, is expected to close in the first quarter.