What the trial was testing
The MOUNTAINEER enrolled 117 patients with colorectal cancer. The study was sponsored by Seagen and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was initial testing (phase 2). Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.
What the results showed
38% tumor response rate in chemo-refractory HER2+ colon cancer.
The Lancet Oncology · 2023 · NCT03043313
These findings — that in chemotherapy-refractory HER2-positive metastatic colorectal cancer — were published in the The Lancet Oncology and represent the headline result of the study.
Researchers tracked outcomes across 117 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.
What this means for patients
For patients with colorectal cancer, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.
What you can do now
Tucatinib (Tukysa) plus trastuzumab is FDA-approved and available now for chemotherapy-refractory HER2-positive metastatic colorectal cancer — the first targeted regimen specifically approved for this group. Ask an oncologist about HER2 testing on your tumor.
Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.
Open colorectal cancer trials
Colonoscopy vs Stool Testing for Older Adults With Colon Polyps
This is a multi-site comparative effectiveness randomized controlled trial (RCT) comparing annual fecal immunochemical testing (FIT) and colonoscopy for post-polypectomy surveillance among adults aged 65-82 with a history of colorectal polyps who are due for surveillance colonoscopy.
Study of Brain-Gut Function Reconstruction After Intersphincteric Resection for Ultra-Low Rectal Tumors
To investigate the effects of intersphincteric resection (ISR) of ultra-low rectal tumor on the brain-rectoanal function of patients, and to precisely localize the cerebral functional regulatory regions for intervention targets of anorectal remodeling. Utilizing transcranial magnetic stimulation(TMS) technology to explore the functional remodeling of the "new" anorectal muscle groups and provide a theoretical basis for more research on the rehabilitation and mechanism of fecal incontinence.