Hernexeos is an oral tyrosine kinase inhibitor used to treat adult patients with unresectable or metastatic non-squamous non-small cell lung cancer (NSCLC) whose tumors harbor HER2 (ERBB2) tyrosine kinase domain (TKD) activating mutations. Treatment is indicated following prior systemic therapy, and eligibility requires confirmation of the HER2 mutation via an FDA-approved test.