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A targeted antibody therapy combined with standard chemotherapy has shown early signs of tumour shrinkage and disease control in patients with advanced bowel cancer, according to new Phase I clinical trial results from The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust.
Results from the ongoing ozekibart INBRX-109 clinical trial, a first-in-human early-phase study involving 50 patients with metastatic colorectal cancer whose disease had progressed after two or three previous treatments and were not eligible for surgery, will be presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting.
The trial was a non-randomised, single-arm study, meaning all patients received the same therapy so researchers could further assess its safety and early effectiveness.
The trial, involving patients across the UK and internationally, is evaluating ozekibart, an investigational antibody therapy designed to trigger cancer cell death by activating a protein called death receptor 5 on the cell surface, in combination with FOLFIRI chemotherapy, a standard treatment for advanced colorectal cancer.
20 per cent of patients saw their tumour shrink
Among 45 evaluable patients in the study, who had a measurable data response, one in five (20 per cent) experienced tumour shrinkage following treatment with ozekibart plus FOLFIRI. One patient experienced complete response, meaning there was no visible tumour on their scan. Patients were deemed evaluable when they had completed enough treatment and scans for researchers to measure how well the treatment was working.
Disease control was achieved in 39 out of 45 patients (87 per cent), including those whose tumours shrank and those whose disease remained stable.
Patients involved in the study were aged between 29-77 years old and had metastatic colorectal cancer that had progressed after two or three previous lines of treatment, meaning their disease had continued to grow despite prior chemotherapy and targeted treatments, leaving limited remaining treatment options. Patients on the trial received ozekibart once every four weeks, alongside standard FOLFIRI chemotherapy, every two weeks.
Outcomes for patients whose disease has progressed after standard therapies are typically poor, with limited response rates to further chemotherapy based treatment regimens.
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The ozekibart plus FOLFIRI combination was generally well tolerated, with a safety profile broadly consistent with FOLFIRI chemotherapy alone. The most common side effects included anaemia, diarrhoea, nausea, fatigue and alopecia, with most adverse events reported as low grade. The findings support further evaluation of ozekibart in combination with chemotherapy in patients with advanced colorectal cancer, particularly those who have exhausted standard treatment options.
'A promising new treatment option'
Dr Hazel Lote, Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust and Honorary Researcher at The Institute of Cancer Research, London, and Gastrointestinal Unit Sub Investigator of the study, said:
“These early results are promising for patients with advanced colorectal cancer who have very few treatment options left. The combination of ozekibart plus FOLFIR not only shrank tumours in some patients, but stopped the cancer from worsening in many others, suggesting this treatment combination could offer a promising new treatment option. While this is still an early-stage trial, the findings are really encouraging for this patient group where there are very few treatment options and supports further research into this treatment.”
'I went from despair to sensing hope'
Amanda Burgess, 59, from East Sussex was diagnosed with colorectal cancer in April 2024 and joined the trial at The Royal Marsden in July last year.
“I had an emergency operation to remove a tumour and following surgery I was told that the cancer had spread. Chemotherapy and immunotherapy followed but unfortunately, they weren’t successful. I then discovered there was a trial opening at The Royal Marsden which I was eligible for, I went from despair to sensing hope.
"This new treatment has given me a new lease of life. Since starting the trial, I’ve had two significant reductions in the size of my tumour and things are now stable.
"The chemotherapy has been hard at times, but I’ve had no side effects from the trial drug itself. My energy has returned, and I’m back to doing the things I love. I walk my black labs Cromwell and Pip, every day, I’m playing tennis, attending Pilates classes and spending time with my husband, David, and our children. I feel incredibly fortunate to be on the trial.”
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The ozekibart study is funded by Inhibrx Biosciences, Inc. Dr Hazel Lote is funded thanks to The Bowelbabe Fund for Cancer Research UK’s generous support of The Royal Marsden Cancer Charity.
