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RecruitingLast updated: 28 March 2024

MOUNTAINEER-03: This phase III study is seeking to understand whether targeted therapy (tucatinib + trastuzumab) plus combination chemotherapy (mFOLFOX6) works better than standard of care treatment regimens (such as mFOLFOX6 alone, or given with either cetuximab or bevacizumab), in people with HER2 positive colorectal cancerAn Open-label Randomized Phase 3 Study of Tucatinib in Combination With Trastuzumab and mFOLFOX6 Versus mFOLFOX6 Given With or Without Either Cetuximab or Bevacizumab as First-line Treatment for Subjects With HER2+ Metastatic Colorectal Cancer

Clinical summary

Summary

Eligible participants will be randomly allocated to either the Experimental Arm or the Active Comparator Arm.

In the Experimental Arm, participants will receive tucatinib + trastuzumab + mFOLFOX6. Tucatinib will be given orally twice daily at a dose of 300mg. Trastuzumab will be given intravenously (IV) first at a 8mg/kg loading dose on Cycle 1 day 1, followed by 6mg/kg every 3 weeks after that. mFOLFOX6 consists of oxaliplatin, fluorouracil + either leucovorin or levoleucovorin. Oxaliplatin will be given via IV every 2 weeks at a dose of 85mg/m2. Leucovorin will be given via IV every 2 weeks at a dose of 400mg/m2. Levoleucovorin will be given via IV every 2 weeks at a dose of 200mg, and may be given in place of leucovorin. Finally, fluorouracil will be given by IV bolus at a dose of 400mg/m2, then 2400mg/m2 given by continuous IV infusion every 2 weeks.

In the Active Comparator Arm, participants will receive one of three standard of care treatment regiments: mFOLFOX6 alone, mFOLFOX6 + bevacizumab, or mFOLFOX6 + cetuximab. mFOLFOX6 will be given as described in the Experimental Arm. Where bevacizumab is given, it will be administered via IV every 2 weeks at a dose of 5mg/kg. Where cetuximab is given, it will be administered via IV first at a 400mg/m2 loading dose on Cycle 1 day 1, followed by 250mg/m2 by IV weekly.

Conditions

This trial is treating patients with HER2+ bowel cancer

Cancer

Bowel Cancers Lower gastrointestinal tract

Age

People18+

Phase

III

Trial Acronym

MOUNTAINEER-03

More information

Trial Identifiers

Use the hyperlinks, where available to access additional clinical trial information.

Trial sponsor

Seagen Inc.

Scientific Title

An Open-label Randomized Phase 3 Study of Tucatinib in Combination With Trastuzumab and mFOLFOX6 Versus mFOLFOX6 Given With or Without Either Cetuximab or Bevacizumab as First-line Treatment for Subjects With HER2+ Metastatic Colorectal Cancer

Eligibility

Inclusion

  • Histologically and/or cytologically confirmed adenocarcinoma of the colon or rectum which is locally advanced unresectable or metastatic
  • Able to provide the most recently available formalin-fixed paraffin-embedded (FFPE) tumor tissue blocks (or freshly sectioned slides) obtained prior to treatment initiation to a central laboratory

    • If archival tissue is not available, a newly-obtained baseline biopsy of an accessible tumor lesion is required within 35 days prior to start of study treatment
  • HER2+ disease as determined by a tissue based assay performed at a central laboratory.
  • Participant has rat sarcoma viral oncogene homolog wild-type (RAS WT) disease as determined by local or central testing. For central RAS analysis, tissue sample must be analyzed within 1 year of biopsy date.
  • Radiographically measurable disease per RECIST v1.1 with:

    • At least one site of disease that is measurable and that has not been previously irradiated, or
    • If the participant has had previous radiation to the target lesion(s), there must be evidence of progression since the radiation
  • Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1
  • CNS Inclusion - based on contrast brain magnetic resonance imaging, participants may have any of the following:

    • No evidence of brain metastases
    • Previously treated brain metastases which are asymptomatic

Exclusion

  • Prior systemic anticancer therapy for colorectal cancer (CRC) in the metastatic setting; note that participants may have received a maximum of 2 doses of mFOLFOX6 in the locally advanced/unresectable or metastatic setting prior to randomization.

    • Note: May have received chemotherapy for CRC in the adjuvant setting if it was completed >6 months prior to enrollment
  • Radiation therapy within 14 days prior to enrollment (or within 7 days in the setting of stereotactic radiosurgery)
  • Previous treatment with anti-HER2 therapy
  • Ongoing Grade 3 or higher neuropathy
  • GI perforation within 12 months of enrollment

Inclusion

  • Your cancer has not spread to other parts of the body.
  • Your cancer has spread to other parts of the body.

Exclusion

  • You have certain types of non-cancer medical conditions.
  • You have had certain treatments, surgical procedures or drugs.
Message

Clinical trials have complex eligibility criteria.

Ask your doctor if this trial could be right for you.

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