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MOUNTAINEER

MOUNTAINEER: A Phase II, Open Label Study of Tucatinib Combined With Trastuzumab in Patients With HER2+ Metastatic Colorectal Cancer

Phase 2N = 117NCT03043313

Population
Chemotherapy-refractory, HER2-positive, RAS wild-type unresectable or metastatic colorectal cancer
Design
Global, open-label phase 2 study at 34 sites in five countries. Initially single-cohort (cohort A, tucatinib 300 mg twice daily plus trastuzumab); after an interim analysis, patients were randomised 4:3 to tucatinib plus trastuzumab (cohort B) or tucatinib alone (cohort C). The primary endpoint was confirmed objective response rate per blinded independent central review in cohorts A and B combined.
Primary endpoint
ORR
Arms
  • Tucatinib + trastuzumab (cohorts A and B) (experimental, n = 84): Tucatinib 300 mg orally twice daily plus intravenous trastuzumab
  • Tucatinib alone (cohort C) (experimental, n = 30): Tucatinib 300 mg orally twice daily
People
Strickler JH
Show the numbers
Results reported for MOUNTAINEER
EndpointAnalysisTucatinib + trastuzumab (cohorts A and B) / Tucatinib alone (cohort C)ControlEffect
ORR84 patients in cohorts A and B in the full analysis set (HER2-positive by local assessment, at least one dose)Confirmed objective response rate per blinded independent central review, cohorts A and B combined (primary endpoint)primaryStrickler 202338.1% (27.7–49.3%)—Three complete and 29 partial responses. Cohort C (tucatinib alone, 30 patients) is not reported as a response rate in the abstract. Cohort B was randomised against cohort C, but the primary endpoint combines cohorts A and B; no comparison between arms is made.
Results reported for MOUNTAINEER
EndpointAnalysisTucatinib + trastuzumab (cohorts A and B) / Tucatinib alone (cohort C)ControlEffect
ORR84 patients in cohorts A and B in the full analysis set (HER2-positive by local assessment, at least one dose)Confirmed objective response rate per blinded independent central review, cohorts A and B combined (primary endpoint)primaryStrickler 202338.1% (27.7–49.3%)—Three complete and 29 partial responses. Cohort C (tucatinib alone, 30 patients) is not reported as a response rate in the abstract. Cohort B was randomised against cohort C, but the primary endpoint combines cohorts A and B; no comparison between arms is made.
Primary publication: Strickler JH, Cercek A, Siena S, André T, Ng K, Van Cutsem E, et al. Tucatinib plus trastuzumab for chemotherapy-refractory, HER2-positive, RAS wild-type unresectable or metastatic colorectal cancer (MOUNTAINEER): a multicentre, open-label, phase 2 study. Lancet Oncol. 2023;24(5):496-508. PubMedDOI

Appears in

Sources

  1. Strickler JH, Cercek A, Siena S, André T, Ng K, Van Cutsem E, et al. Tucatinib plus trastuzumab for chemotherapy-refractory, HER2-positive, RAS wild-type unresectable or metastatic colorectal cancer (MOUNTAINEER): a multicentre, open-label, phase 2 study. Lancet Oncol. 2023;24(5):496-508.

    PubMedDOI