Indirect comparisons of tucatinib in combination with trastuzumab for patients with previously treated HER2-positive metastatic colorectal cancer.

Aim: In the single-arm MOUNTAINEER trial (NCT03043313) tucatinib in combination with trastuzumab showed an objective response rate (ORR) of 39.3% in patients with previously treated, HER2+ unresectable or metastatic colorectal cancer (mCRC). This study compared the efficacy of tucatinib in combination with trastuzumab with other treatment options in this population. Materials versus trifluridine-tipiracil, this was 0.34 (0.22-0.51) for OS and 0.38 (0.20-0.58) for PFS. Similar results were seen for OS and PFS in sensitivity analyses. ORR also favored tucatinib in combination with trastuzumab across analyses. Conclusion: These data support that tucatinib in combination with trastuzumab is an effective therapy option in patients with previously treated mCRC.