Seagen Announces Positive Topline Results of Pivotal Phase 2 Clinical Trial of TUKYSA(R) (tucatinib) in Combination With Trastuzumab in HER2-Positive Metastatic Colorectal Cancer

Strategic Insights -

Seagen Inc. announced positive topline results from the pivotal phase 2 MOUNTAINEER clinical trial investigating TUKYSA(R) (tucatinib) in combination with trastuzumab in patients with previously treated HER2-positive metastatic colorectal cancer. The combination of tucatinib and trastuzumab showed a 38.1% confirmed objective response rate (cORR) with a median duration of response (DoR) of 12.4 months. The combination was generally well-tolerated, with the most common adverse events being diarrhea, fatigue, nausea, and infusion-related reaction.

The MOUNTAINEER trial is a U.S. and European multicenter, open-label, phase 2 clinical trial of tucatinib in combination with trastuzumab or as a single agent in 117 patients with HER2-positive metastatic or unresectable colorectal cancer following previous standard-of-care therapies. The primary endpoint of the trial is confirmed objective response rate by RECIST version 1.1 criteria per blinded independent central review in patients receiving the combination of tucatinib and trastuzumab. Duration of response, progression-free survival, overall survival, and safety and tolerability of the combination regimen are secondary objectives.

Key Takeaways:

  • The combination of tucatinib and trastuzumab showed a 38.1% confirmed objective response rate (cORR) with a median duration of response (DoR) of 12.4 months.
  • The combination was generally well-tolerated, with the most common adverse events being diarrhea, fatigue, nausea, and infusion-related reaction.
  • The MOUNTAINEER trial enrolled 117 patients with HER2-positive metastatic or unresectable colorectal cancer following previous standard-of-care therapies.
  • The primary endpoint of the trial is confirmed objective response rate by RECIST version 1.1 criteria per blinded independent central review in patients receiving the combination of tucatinib and trastuzumab.
  • TUKYSA is an oral medicine that is a tyrosine kinase inhibitor of the HER2 protein and is approved in 36 countries.
  • Colorectal cancer is the third leading cause of cancer-related deaths in the U.S. and is anticipated to lead to about 52,580 deaths in 2022.
  • Human epidermal growth factor receptor 2 (HER2) is overexpressed in 3-5% of patients with metastatic colorectal cancer.

Statistics:

  • 38.1% confirmed objective response rate (cORR) with a median duration of response (DoR) of 12.4 months
  • 117 patients enrolled in the MOUNTAINEER trial
  • 52,580 deaths anticipated in the U.S. due to colorectal cancer in 2022
  • 3-5% of patients with metastatic colorectal cancer have overexpression of HER2

Sources:

  • "Seagen Announces Positive Topline Results of Pivotal Phase 2 Clinical Trial of TUKYSA(R) (tucatinib) in Combination With Trastuzumab in HER2-Positive Metastatic Colorectal Cancer" Seagen Inc. (2022)
  • "MOUNTAINEER Clinical Trial" Seagen Inc.
  • "TUKYSA(R) (tucatinib)" Seagen Inc.
  • "Colorectal Cancer Statistics" American Cancer Society (2022)
  • "HER2-Positive Metastatic Colorectal Cancer" National Cancer Institute (2022)