Gilead Boosts Cancer Focus With $21 Billion Immunomedics Buy (4)

Gilead Sciences Inc. agreed to acquire Immunomedics Inc. for about $21 billion, a substantial premium for the maker of a promising breast-cancer therapy, and another big bet by Gilead that an innovative tumor-fighting drug can boost its fortunes.

The proposed $88-a-share deal values Immunomedics at more than twice its closing price of $42.25 on Friday. The New Jersey-based company makes a breast-cancer treatment called Trodelvy that gained approval from the U.S. Food and Drug Administration in April. Since then, its stock has soared on bets that the clearance could make Immunomedics an attractive takeover target.

Trodelvy’s approval came after clinical ...