Trial of ZW25 (Zanidatamab) in Patients With Advanced HER2-expressing Cancers

Part 1 of the study will evaluate increasing doses of ZW25 to find the highest dose of ZW25 that does not cause unacceptable side effects (maximum-tolerated dose or MTD), the lowest safe dose with the highest rate of effectiveness (optimal biological dose or OBD), and/or other recommended dosages (RDs) of ZW25 in up to 7 dose-specific cohorts. Eligible patients include those with selected HER2-expressing locally advanced (unresectable) and/or metastatic cancers that have progressed after receipt of all therapies known to confer clinical benefit (or ineligible to receive therapy). Part 2 of the study will further evaluate the safety, tolerability, and efficacy of ZW25 in patients with selected HER2-expressing locally advanced (unresectable) and/or metastatic cancers that have progressed after receipt of all therapies known to confer clinical benefit (or ineligible to receive therapy) in up to 5 separate disease-specific cohorts. Part 3 of the study will evaluate the safety, tolerability, and efficacy of ZW25 combined with selected chemotherapy agents, including paclitaxel, capecitabine, vinorelbine, or capecitabine and tucatinib. Patients with selected HER2-expressing locally advanced (unresectable) and/or metastatic cancers that have progressed after at least 1 and no more than 3 prior systemic chemotherapy regimens will be evaluated in this part of the study.