Trial results for the Phase 2 study investigating pembrolizumab and vactosertib as preoperative treatment for colorectal cancer with resectable hepatic metastases were posted on ClinicalTrials.gov on 2025-12-31. The study reported that the proportion of participants with a pathologic response was 0, indicating no observed pathologic response to the treatment.
Background
Pembrolizumab (Keytruda) is an immunotherapy drug, a monoclonal antibody designed to help the body's immune system attack cancer cells. Vactosertib is an investigational agent that may stop the growth of tumor cells by blocking enzymes needed for cell growth. This study explored their use in patients with colorectal cancer that has spread to the liver and can be surgically removed.
Trial design
The study (NCT03844750) was a Phase 2 trial, which enrolled 6 participants. It investigated pembrolizumab and vactosertib given after standard of care chemotherapy in patients with Stage IV colorectal cancer, including Stage IVA, Stage IVB, and Stage IVC, with resectable hepatic metastases. The trial was terminated.
Key results
Key measurements from the trial, for the 'Treatment (vactosertib, pembrolizumab, surgery)' group, included:
- The proportion of participants with treatment-related adverse events was 1.00.
- The proportion of participants with events of clinical interest (ECIs) was 0.33.
- The proportion of participants with perioperative complications was 0.17.
- The proportion of participants with an R0 resection (complete removal of all tumor tissue with clear margins) was 0.83.
- The proportion of participants with a pathologic response was 0.
- The median relapse-free survival (RFS) was 14.51 months.
What this means
The results from this Phase 2 trial indicate that while a high proportion of participants (0.83) achieved an R0 resection, no pathologic response was observed in any participant. The median relapse-free survival was 14.51 months. All participants experienced treatment-related adverse events, with a proportion of 0.33 having events of clinical interest. The trial's termination and the lack of pathologic response suggest that this specific preoperative regimen of pembrolizumab and vactosertib may not be effective in inducing a pathologic response in this patient population, despite successful surgical resections in most participants.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03844750, titled 'Preoperative Immunotherapy (Pembrolizumab) for Patients With Colorectal Cancer and Resectable Hepatic Metastases,' were posted on 2025-12-31 on clinicaltrials.gov.