Gilead Sciences Inc. (NASDAQ: GILD) is gearing up to purchase drug innovator Immunomedics Inc. (NASDAQ: IMMU) for a price tag exceeding $20 billion.Per the Wall Street Journal, Immunomedics — a biotech known for breast-cancer treatment Trodelvy — was initially a partner of Gilead before takeover talks began. Terms are expected to be announced Monday. Immunomedics, whose valuation hovers $10 billion, is just the latest in a series of deals Gilead made in 2020.In June, Foster City, California-based Gilead acquired a 49.9% stake in cancer drug developer Pionyr Immunotherapeutics for $275 million. Before that, it spent $4.9 billion for Forty Seven Inc., a company that makes blood cancer treatments.Gilead closed Friday, Sept. 11 at $65.58 a share, while Immunomedics shares closed at $41.93.See more from Benzinga * SoftBank Close To Selling Chip Designer To Nvidia For B * CBD Saved This Exec's Life: Now He's Launching His Own 'Connoisseur Cannabis' Brand * Amyris Denies 'Patent Infringement' Allegations On Heels Of 1M Lavvan Lawsuit(C) 2020 Benzinga.com. Benzinga does not provide investment advice. All rights reserved.