Dr. Strickler on the Efficacy of Tucatinib/Trastuzumab in HER2+ Colorectal Cancer

John H. Strickler, MD, medical oncologist, Duke Cancer Center, Duke Health, discusses the efficacy of tucatinib (Tukysa) plus trastuzumab (Herceptin) in HER2-positive colorectal cancer (CRC).

The phase 2 MOUNTAINEER trial (NCT03043313) examined the safety and efficacy of tucatinib in combination with trastuzumab or tucatinib alone in patients with HER2-positive CRC.

The randomized, open label study met its primary endpoint of overall response rate (ORR) per blinded independent central review, Strickler says. The 84 patients who received the tucatinib/trastuzumab combination achieved an ORR 38.1%, and the investigator-assessed ORR was 43%, Strickler explains. Notably, the responses were durable, with median duration of response greater of 12.4 months, Strickler adds. The progression-free survival was 8.2 months, and the median overall survival was 24.1 months, Stickler continues.

The hope is to see this meaningful clinical activity translate to practice, Strickler continues. The regimen was well tolerated, with most of the adverse effects experienced were mild to moderate in severity, Strickler says. No treatment-related deaths were reported, and most patients found the regimen manageable with routine supportive care, Strickler concludes.