Dr Bekaii-Saab on the Final Analysis of MOUNTAINEER in HER2+ CRC

Tanios Bekaii-Saab, MD, FACP, professor, medicine, Mayo Clinic College of Medicine and Science; leader, Gastrointestinal Cancer Program, Mayo Clinic Comprehensive Cancer Center; medical director, Cancer Clinical Research Office; vice chair, section chief, Medical Oncology, Department of Internal Medicine, Mayo Clinic, discusses final efficacy and safety data from the phase 2 MOUNTAINEER trial (NCT03043313) in patients with HER2-positive metastatic colorectal cancer (mCRC).

Tucatinib (Tukysa) plus trastuzumab (Herceptin) generated sustained efficacy in chemotherapy-refractory, RAS wild-type, HER2-positive mCRC in the final analysis of MOUNTAINEER. The combination yielded clinically meaningful activity with longer follow-up, establishing it as an important chemotherapy-free treatment option for HER2-positive mCRC. The combination is being further evaluated in the first-line HER2-positive mCRC setting with the addition of chemotherapy in the ongoing phase 3 MOUNTAINEER-03 trial (NCT05253651).

The updated findings from the MOUNTAINEER trial in HER2-positive mCRC highlight the sustained efficacy of tucatinib plus trastuzumab, Bekaii-Saab begins. The long-term follow-up data show that the combination maintains significant activity across a broad spectrum of patients, with durable responses and high survival rates, he explains. Impressively, some patients have experienced complete responses lasting over 5 years, according to Bekaii-Saab. These findings reinforce the combination’s role as the primary treatment choice for HER2-positive mCRC, as it has demonstrated more promising results compared with other therapies, including salvage trastuzumab, Bekaii-Saab states.

The continued success of tucatinib plus trastuzumab in generating progression-free survival outcomes and achieving high response rates, even with extended follow-up, underscores the combination’s importance in treating patients with this cancer subtype, he expands. The durability of the responses is particularly notable, as it indicates the potential for long-term disease control with this regimen, Bekaii-Saab reports.

This trial update was part of a broader discussion of advancements in cancer treatment that were presented at the 2024 ASCO Annual Meeting, he continues. More detailed findings and new data from cancer clinical trials are anticipated to be presented at upcoming conferences, including the 2024 ESMO Congress, Bekaii-Saab states. These conferences will further explore the complexities and evolving treatment patterns in oncology, providing critical insights into improving patient outcomes, he concludes.