GSK's GSK5764227 (GSK’227), a B7-H3-targeted antibody-drug conjugate, received FDA Breakthrough Therapy Designation for treating relapsed or refractory osteosarcoma, a rare bone cancer with no approved treatments post two prior therapies. This designation aims to expedite development, supported by ARTEMIS-002 study data, highlighting GSK’227's potential in addressing unmet medical needs in difficult-to-treat cancers.