CHICAGO — Zanidatamab exhibited durable antitumor activity among patients with previously treated advanced HER2-amplified biliary tract cancer, according to results of the phase 2B HERIZON-BTC-01 study presented at ASCO Annual Meeting.More than half of patients who received zanidatamb (Jazz Pharmaceuticals/Zymeworks) monotherapy survived at least a year and median OS exceeded 15 months.