Irwin

Researchers are evaluating whether tucatinib combined with trastuzumab and mFOLFOX6 works better than the standard treatments for people with HER2 positive metastatic colorectal cancer, which is cancer that has spread or cannot be removed by surgery. This phase 3 study also aims to identify the side effects that may occur with this drug combination. Participants must have HER2 positive disease confirmed by testing and measurable cancer according to specific criteria. Participants will be randomly assigned to one of two groups. One group will receive tucatinib taken orally twice daily along with intravenous trastuzumab and the mFOLFOX6 chemotherapy regimen, which includes oxaliplatin, leucovorin or levoleucovorin, and fluorouracil given by IV every two weeks. The other group will receive standard care, which could be mFOLFOX6 alone or combined with either bevacizumab or cetuximab, both given by IV on specific schedules. Treatment continues as per the study protocol. During the study, participants will be monitored for progression-free survival up to about three years using imaging reviewed by independent experts. Researchers will assess side effects and disease response. Participants must be able to provide tumor tissue samples for testing and have a good performance status. The study includes brain imaging to check for metastases and monitors safety closely throughout the treatment period.