Jazz Pharmaceuticals announced on Friday the FDA approval of ZIIHERA (zanidatamab) for heavily pretreated gastroesophageal junction and HER2-positive gastric cancer, triggering a 4.7% increase in the company's shares, while immediately boosting AstraZeneca’s prospects as the co-developer of the targeted antibody-drug conjugate. The authorization is expected to reshape the HER2-targeted oncology landscape, where Jazz positions Ziihera to compete directly against major blockbusters and disrupt standard-of-care treatment paradigms.