Population pharmacokinetics of zanidatamab, an anti-HER2 biparatopic antibody, in patients with advanced or metastatic cancer.

Purpose: To characterize the pharmacokinetics (PK) of zanidatamab including evaluation of the impact of intrinsic and extrinsic patient factors. To investigate alternative dosing regimens to improve caregiver convenience and reduce zanidatamab wastage.

Methods: Serum zanidatamab concentrations were obtained from 305 patients with advanced or metastatic breast cancer, gastroesophageal adenocarcinoma (GEA), biliary tract cancer, and other HER2-expressing cancers from four ongoing phase I and II clinical trials.