Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Trastuzumab and tucatinib for the treatment of HER2 amplified metastatic colorectal cancer (mCRC): Initial results from the MOUNTAINEER trial

Date

29 Sep 2019

Session

Poster Discussion – Gastrointestinal tumours, colorectal

Presenters

John Strickler

Citation

Annals of Oncology (2019) 30 (suppl_5): v198-v252. 10.1093/annonc/mdz246

Authors

J.H. Strickler1, T. Zemla2, F. Ou2, A. Cercek3, C. Wu4, F.A. Sanchez5, J. Hubbard6, B. Jaszewski6, L. Bandel6, B. Schweitzer6, D. Niedzwiecki7, N. Kemeny3, P.M. Boland8, K. Ng9, T. Bekaii-Saab10

Author affiliations

  • 1 Medicine, Division Of Medical Oncology, Duke University Medical Center, 27710 - Durham/US
  • 2 Department Of Health Sciences Research, Mayo Clinic, 55905 - Rochester/US
  • 3 Medical Oncology, Memorial Sloan Kettering Cancer Center, 10065 - New York/US
  • 4 Hematology And Medical Oncology, Emory University, 30322-1013 - Atlanta/US
  • 5 Advocate Aurora Health, Aurora Cancer Care, 53215 - Milwaukee/US
  • 6 Medical Oncology, Mayo Clinic, 55905 - Rochester/US
  • 7 Biostatistics And Bioinformatics, Duke University Medical Center, 27705 - Durham/US
  • 8 Internal Medicine, Roswell Park Comprehensive Cancer Center, 14203 - Buffalo/US
  • 9 Medical Oncology, Dana-Farber Cancer Institute, 02215 - Boston/US
  • 10 Medical Oncology, Mayo Clinic Cancer Center, 85054 - Phoenix/US
More

Resources

Background

HER2 (ERBB2) amplification is present in 5-10% of patients (pts) with KRAS and NRAS (RAS) WT mCRC. Tucatinib (Seattle Genetics, Bothell, WA) is a potent, highly selective oral tyrosine kinase inhibitor of the HER2 receptor. In patient-derived xenograft models of HER2+ mCRC, the combination of tucatinib and trastuzumab showed significantly greater antitumor activity compared with tucatinib or trastuzumab alone. Here we present initial results from a trial of tucatinib and trastuzumab in pts with HER2 amplified mCRC.

Methods

MOUNTAINEER is a multicenter open-label single-arm phase II trial. Pts with RAS WT mCRC had HER2 amplification/overexpression by NGS, FISH, or IHC (3+ or 2+ and amplified by FISH). Prior treatment with 5FU, oxaliplatin, irinotecan, and an anti-VEGF antibody was required. Prior anti-HER2 therapy was excluded. Pts received tucatinib 300mg PO bid and standard doses of trastuzumab (IV, Q3 weeks). The primary endpoint was objective response rate (ORR) per RECIST v1.1. Using a 2-Stage Fleming design, this study compared ORR of 20% (null) vs 40% (alt) in 10 or 25 evaluable pts (1-sided α = 0.11; β=.16). At least 8 responses were needed to meet the primary efficacy endpoint.

Results

As of 26 April 2019, 26 pts enrolled, and 22 pts completed ≥1 evaluation of response. 16/26 pts (62%) were male. Median age= 52.5 (range 24-70). The primary tumor site of origin included right colon (N = 4), left colon/rectum (N = 17), transverse colon (N = 3), and overlapping (N = 2). Among 22 evaluable pts, ORR= 55% (CR/PR= 12; SD = 5; PD = 5). Clinical benefit rate (CR+PR+SD≥4 months) = 64%. At a median follow-up of 10.6 months, median PFS= 6.2 months (95% CI 3.5-NE). Median OS = 17.3 months (95% CI 12.3-NE). Median duration of response has not been reached. There were 2 (9%) grade 3 treatment-related adverse events (TRAEs) and no grade 4/5 TRAEs. The most common TRAEs were AST elevation (48%; all G1), ALT elevation (30%; all G1), and diarrhea (26%; G1/G2/G3=4%/17%/4%).

Conclusions

The combination of tucatinib and trastuzumab is well tolerated and has met its primary efficacy endpoint. Based on these results, further expansion of the MOUNTAINEER trial in pts with HER2 amplified mCRC is justified. Updated results will be presented.

Clinical trial identification

NCT03043313.

Editorial acknowledgement

Legal entity responsible for the study

Academic and Community Cancer Research United.

Funding

Seattle Genetics.

Disclosure

J.H. Strickler: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Amgen; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self): Chugai; Advisory / Consultancy, Research grant / Funding (institution): Genentech/Roche; Advisory / Consultancy, Research grant / Funding (institution): AstraZeneca; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Seattle Genetics; Advisory / Consultancy, Research grant / Funding (institution), Shareholder / Stockholder / Stock options, Non-remunerated activity/ies: OncoMed; Advisory / Consultancy: Celgene; Advisory / Consultancy: Proteus Digital Health; Advisory / Consultancy: Chengdu Kanghong Biotechnology Ltd; Research grant / Funding (institution): Exelixis; Research grant / Funding (institution): Sanofi; Research grant / Funding (institution): Nektar; Research grant / Funding (institution): AbbVie; Research grant / Funding (institution): Gilead Sciences; Research grant / Funding (institution): Macrogenics; Research grant / Funding (institution): Leap Therapeutics. A. Cercek: Advisory / Consultancy: Bayer; Advisory / Consultancy: Proteus; Research grant / Funding (institution): Seattle Genetics. C. Wu: Research grant / Funding (institution): Vaccinex; Research grant / Funding (institution): Boston Biomedical; Research grant / Funding (institution): Lycera; Research grant / Funding (institution): Seattle Genetics; Research grant / Funding (institution): Symphogen; Research grant / Funding (institution): FLX Bio. J. Hubbard: Research grant / Funding (institution): Seattle Genetics; Honoraria (institution), Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Merck; Research grant / Funding (institution): Boston Biomedical; Research grant / Funding (institution): Treos Bio; Research grant / Funding (institution): Taiho; Research grant / Funding (institution): Senhwa pharmaceuticals. N. Kemeny: Research grant / Funding (institution): Amgen. P.M. Boland: Research grant / Funding (institution): Merck; Research grant / Funding (institution): Genentech/Roche; Research grant / Funding (institution): Boehringer Ingelheim; Research grant / Funding (institution): Hemispherx; Research grant / Funding (institution): Boston Biomedical; Research grant / Funding (institution): Isofol Medical; Research grant / Funding (institution), Travel / Accommodation / Expenses: Ipsen; Research grant / Funding (institution): Athenex; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Clinical Genomics. K. Ng: Advisory / Consultancy, Research grant / Funding (institution): Genentech; Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: Tarrex Biopharma; Advisory / Consultancy: Bayer; Advisory / Consultancy, Research grant / Funding (institution): Seattle Genetics; Research grant / Funding (institution): Gilead Sciences; Research grant / Funding (institution): Trovagene; Research grant / Funding (institution): Celgene; Research grant / Funding (institution): Pharmavite; Research grant / Funding (institution): Consano. T. Bekaii-Saab: Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Seattle Genetics. All other authors have declared no conflicts of interest.

Resources from the same session

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings