HIGHLIGHTS • Phase I study of tucatinib and trastuzumab in patients with progressive HER2-positive breast cancer brain metastasis • Two cohorts enrolled: cohort A, twice-daily (BID) tucatinib and cohort B, once-daily (QD) tucatinib • The maximum tolerated dose of tucatinib was 300 mg PO BID in cohort A and 750 mg PO QD in cohort B • The combination of tucatinib and trastuzumab was well tolerated • We observed preliminary evidence of activity, including intracranial responses ABSTRACT...
