Dr. Strickler on the Importance of Targeted Therapies in HER2+ mCRC

John H. Strickler, MD, associate professor of medicine, Duke University School of Medicine, medical oncologist, Duke Cancer Institute, discusses the importance of investigating targeted therapies in HER2-positive metastatic colorectal cancer (mCRC). 

The phase 2 MOUNTAINEER trial (NCT03043313) examined the efficacy of tucatinib (Tukysa) monotherapy and in combination with trastuzumab (Herceptin) in patients with previously treated HER2-positive mCRC.

Approximately 3% of patients with mCRC overexpress HER2, and those rates increase to up to 10% for patients with RAS or BRAF wild-type disease, Strickler says. Tucatinib is a highly selective TKI and oral therapy that has shown beneficial antitumor activity in other tumor types that overexpress HER2, such as breast cancer, leading to the rationale for investigating this therapy in HER2-positive mCRC, Strickler explains.

In preclinical models of HER2-positive CRC, the combination of trastuzumab and tucatinib effectively inhibited tumor growth and displayed more activity than either trastuzumab or tucatinib alone, Strickler concludes.