Immunogen Inc. shares (NASDAQ:IMGN) climbed 16.8 percent to close at $8.69 Monday as Japanese drugmaker Takeda Pharmaceutical Co. Ltd. pledged $20 million up front plus potential milestones to license exclusive rights to use the company’s antibody-drug conjugate (ADC) technology to develop and commercialize anticancer therapeutics for up to two undisclosed targets with an option on a third.