(Bloomberg) -- AbbVie Inc. agreed to acquire ImmunoGen Inc. for a total equity value of $10.1 billion, delivering the biotech company’s Elahere cancer drug to the pharmaceutical giant. 

AbbVie will acquire all outstanding shares of ImmunoGen for $31.26 a share in cash, the companies said Thursday in a statement. That’s almost double the stock’s last closing price of $16.06 and higher than it has traded in more than 20 years.

AbbVie shares fell 0.4% in trading before US markets opened. ImmunoGen jumped 81%.

Elahere is an antibody-drug conjugate, a type of therapy that precisely targets tumor cells, allowing stronger doses. The field is widely coveted by drugmakers including Pfizer Inc., which is buying Seagen Inc. to gain conjugate cancer drugs. Enhertu from Japan’s Daiichi Sankyo Co. and AstraZeneca Plc is another therapy in the rapidly expanding category. 

The AbbVie-ImmunoGen deal “should be a pretty straight forward merger” with little scrutiny from regulators since the two companies have little overlap in their products, Jared Holz, an analyst at Mizuho, said Thursday in a note. The acquisition helps AbbVie move further into treating solid tumors, Holz said.

Elahere was approved last year in ovarian and fallopian tube cancer.

(Corrects name of AstraZeneca partner in fourth paragraph of story published Nov. 30.)

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