US biopharmaceutical company Gilead Sciences agreed to buy Ouro Medicines, which is developing an antibody-based medicine for autoimmune diseases licensed from China’s Keymed Biosciences, in a deal worth up to US$2.18 billion.Gilead Sciences is among a group of global drug makers facing patent expirations and turning to mergers, acquisitions and licensing deals to refill their drug pipelines.Under the agreement, Gilead Sciences would pay shareholders of US-based Ouro Medicines US$1.675 billion...