.tmb-propic-md.jpg?Culture=en&sfvrsn=c25d2b2f_9 "Professor Louis Chesler (Profile pic)")
A new, targeted cancer therapy for advanced gastrointestinal stromal tumours (GIST) has shown promising early results, with 61 per cent of patients who received velzatinib as first-line treatment experiencing tumour shrinkage of 30 per cent or over. The results could pave the way for a larger trial to evaluate this therapy as a first-line alternative to imatinib, which has been the standard treatment for more than two decades.
Initial results from the ongoing StrateGIST 1 clinical trial, an international, multi-centre Phase 1/1b trial with contributions from The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, have been presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting.
New drug targets mutations in the KIT gene
The trial, involving patients in the UK and internationally, is evaluating velzatinib as a first- and second-line treatment for advanced GIST. Velzatinib is a tyrosine kinase inhibitor (TKI), a type of targeted cancer therapy that works by blocking specific enzymes involved in cell signalling, helping to control cancer cell growth and division.
It is designed to target a broad range of mutations in the KIT gene, including those linked to treatment resistance.
Drawing on data from 66 patients, the researchers found that, of those patients taking velzatinib as their first treatment (N=19), 61 per cent experienced complete or partial reduction in tumour size. For patients who took velzatinib as a second-line treatment (N=47), 35 per cent experienced a reduction in tumour size, with a median of 13.7 months before the disease started to progress.
For 24 years, imatinib has remained an effective, well-tolerated standard treatment for patients with advanced GIST. However, around half of patients will develop resistance to imatinib within two years due to mutations in the KIT gene, causing cells to grow and divide unchecked, and making their tumours more challenging to treat.1 As a result, there is a clinical need for therapies that can target a broader range of KIT mutations and provide longer-term disease control.
The findings from this early-stage trial indicate that velzatinib may be an effective first- and second-line treatment for advanced GIST. It shows positive results across a broad range of relevant KIT mutations as a second-line treatment, and presents a manageable safety profile, with many side effects being mild to moderate and in line with what is typically seen for this type of drug.
Overall, these results are promising and support further evaluation in larger, later-stage studies to better understand its impact on patients.
Initial results are 'very promising'
Professor Robin Jones, Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust and Professor in Sarcoma Oncology at The Institute of Cancer Research, London, who presented the study findings at ASCO, said:
“While imatinib revolutionised treatment when it was first approved more than two decades ago, many patients eventually develop resistant disease and their cancer becomes increasingly difficult to manage. The initial results from this trial are very promising in terms of how long we may be able to control the disease when velzatinib is used as a first- or second-line treatment.
“Critically, these findings allow us to initiate a randomised trial to determine whether velzatinib could become a new first-line treatment for patients living with advanced GIST.”
'The drug is keeping the cancer at bay'
After being diagnosed with an advanced GIST in 2023, Dominic Taplin, 63, a pub owner from West Sussex, was referred to The Royal Marsden and placed on the standard treatment, which initially showed positive results. However, after around two years, the treatment began to lose effectiveness. Dominic then joined the StrateGIST 1 trial at The Royal Marsden in August 2025, where he has been receiving treatment with velzatinib, which is helping to keep his cancer under control. He said:
“After two years of receiving my initial treatment, I was offered the chance to join a clinical trial at The Royal Marsden, which meant being right at the forefront of new treatments.
“The drug is keeping the cancer at bay, and I can do everything I would normally do; it’s not holding me back at all. I’m still working, running my business, and looking after my children—I’m still picking my daughter up from school and even doing things like cleaning the lines at the pub. Without this drug, I wouldn’t be able to do any of that.”
The StrateGIST 1 study is funded by IDRx. Inc., a wholly owned subsidiary of GlaxoSmithKline (GSK).
