Bristol-Myers Squibb Company (NYSE:BMY) will buy 2Seventy Bio Inc (NASDAQ:TSVT)- a firm it has collaborated with in developing cancer treatments- for about $286 million, 2seventy said in a statement on Monday evening. 

2Seventy Bio shares soared 76.4% in premarket trading Tuesday.

2seventy said it had entered a definitive merger agreement with Bristol Myers, under which the biopharmaceutical giant will offer $5 for each share in 2seventy. The figure represents an 78.6% premium to 2seventy’s Monday close of $2.80. 

The two have collaborated on developing several cancer treatments, with the most successful being Abecma, which was approved by the Food and Drug administration last year for use in treating some variants of Myeloma. 

2seventy CEO Chip Baird said Abecma was the main rationale behind Bristol Myers’ takeover, stating that development of the treatment will “continue to benefit from BMS’ experience and resources.” 

Bristol Myers could not be immediately reached for comment.