Dr. Strickler on the Rationale for the MOUNTAINEER-02 Trial in HER2+ Gastric/GEJ Cancer

John H. Strickler, MD, medical oncologist, Duke Cancer Center, Duke Health, discusses the rationale for the phase 2/3 MOUNTAINEER-02 trial (NCT04499924) in HER2-positive gastric/gastroesophageal junction (GEJ) cancer.

MOUNTAINEER-02 is a trial in progress evaluating tucatinib (Tukysa) in combination with trastuzumab (Herceptin), ramucirumab (Cyramza), and paclitaxel versus paclitaxel and ramucirumab in patients with HER2-positive gastric/GEJ cancer.

Tucatinib is a potent small molecule inhibitor of HER2, says Strickler. Additionally, tucatinib is highly selective for HER2, which limits off-target effects and allows the agent to be well tolerated by most patients. The adverse effects observed with tucatinib appear to be manageable based on previously reported data, Strickler says. Moreover, the tolerability of the agent allows it to be combined with other therapies, such as trastuzumab or cytotoxic chemotherapy.

Tucatinib, in combination with capecitabine and trastuzumab, is currently approved for patients with pretreated HER2-positive breast cancer. However, the agent likely has applications in other HER2-positive malignancies, such as gastric/GEJ cancer, concludes Strickler.