Tucatinib and Trastuzumab for HER2-Positive, Metastatic Colorectal Cancer

Prior phase 2 trials have demonstrated consistent activity with various combinations of HER2-targeted agents in patients with HER2-positive, metastatic colorectal cancer (mCRC).

Now, investigators in the U.S. and Europe have conducted an industry-sponsored, randomized, open-label, phase 2 trial (MOUTAINEER) to evaluate dual HER2-targeted therapy with tucatinib and trastuzumab in patients with chemotherapy-refractory, HER2-positive, RAS wild-type mCRC who had received no prior HER2-directed therapy. Among 116 participants, 86 received tucatinib plus trastuzumab, and 30 received tucatinib alone. Of patients who received combination therapy, 85% had left-sided primaries, 78% had received 2 or more lines of prior therapy, and 40% had received 3 …