Paclitaxel and Ramucirumab +/- Zanidatamab in HER2 Postive Advanced Gastroesophageal Adenocarcinoma

Inclusion Criteria

• •Participants must have histologically or pathologically confirmed gastroesophageal adenocarcinoma (stomach, gastroesophageal junction or esophagus) that is unresectable or metastatic and which must be HER2 positive as confirmed by central testing using FDA-approved HER2 assay. HER2 positive is defined as IHC 3+, or IHC 2+ and FISH positive.
• •Participants must have received and failed at least one prior trastuzumab-containing regimen in combination with platinum-based chemotherapy for treatment of locally advanced or metastatic disease. Failure is defined as demonstrated objective disease progression (radiologic) on the most recently administered HER2 targeting agent.
• •Participants must have presence of measurable or evaluable disease as defined by Response Evaluation Criteria in Solid Tumours (RECIST 1.1).
• •Participants must be considered a suitable candidate for, and able to receive chemotherapy for advanced disease with paclitaxel and ramucirumab.
• •Participants must consent to the provision of samples of blood, serum and plasma in order that the specific correlative marker assays may be conducted.
• •Participants must consent to provision of, and investigator(s) must confirm access to a representative formalin fixed paraffin embedded (FFPE) block of tumour tissue/ or a predetermined number of freshly cut slides of representative tumour tissue of adequate amount and quality in order that the central HER2 testing may be done
• •Participants must be ≥ 18 years of age.
• •Participants must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• •Participants must have a life expectancy of at least 12 weeks at the time of study entry
• •Imaging investigations including CT/MRI of chest/abdomen/pelvis or other scans as necessary to document all sites of disease must be done within 28 days prior to randomization
• •Participants must have adequate cardiac function by ECHO or MUGA defined as EF ≥ 50%. This is to be performed within 4 weeks (preferred) but no more than 8 weeks prior to randomization
• •Participants must have adequate normal organ and marrow function
• •Participant is able (i.e. sufficiently fluent) and willing to complete the quality of life and/or health utility questionnaires in either English or French
• •Participant consent must be appropriately obtained in accordance with applicable local and regulatory requirements.
• •Participant must be accessible for treatment and follow-up. Investigators must assure themselves the participants enrolled on this trial will be available for complete documentation of the treatment, adverse events, and follow-up.
• •In accordance with CCTG policy, protocol treatment is to begin within 2 working days of participant enrollment
• •Participants of childbearing potential must have agreed to use a highly effective contraceptive method for the entire period of study treatment and for at least 7 months after discontinuing study therapy.