Tucatinib plus trastuzumab and oxaliplatin-based chemotherapy for HER2+ gastrointestinal cancers - Clinical Trial

We are doing this study to see if the study drug, tucatinib, is safe and effective to use with trastuzumab and oxaliplatin-based chemotherapy. We also want to find the best dose of tucatinib to use to shrink the cancer.

HER2+ Gastrointestinal Cancer

Adults with HER2+ cancer and one of the following tumor types:
-Colorectal carcinoma (cancer of the colon or rectum)
-Gastric adenocarcinoma (a type of stomach cancer)
-Esophageal adenocarcinoma (a type of cancer in the esophagus)
-Gastroesophageal junction adenocarcinoma (a type of cancer that occurs where the esophagus meets the stomach)
-Cholangiocarcinoma (cancer of the bile ducts)
-Gallbladder carcinoma (cancer of the gallbladder)

If you choose to join this study, you will:
-Take the study drug, tucatinib, by mouth twice a day
-Get trastuzumab and chemotherapy every 2 or 3 weeks
-Give blood and urine samples
-Have regular CT or MRI scans