TOKYO & LONDON—Under a recent definitive agreement, Sosei Group Corp. will make an investment in and gain an exclusive option to potentially acquire biopharmaceutical company MiNA Therapeutics. Sosei will invest £35 million into MiNA Therapeutics in return for a 25.6-percent equity share and an exclusive option to acquire further stakes and possibly the company for an additional £140 million. Should Sosei fully exercise its option, MiNA's shareholders could receive up to £240 million based on the achievement of development and regulatory milestones and royalties.