Early results from a global clinical trial show that using a new pill with immunotherapy can shrink tumours by at least 30% or keep them stable in people with six different advanced and hard-to-treat cancers. The drug – GRWD5769 – is being used with an existing type of immunotherapy called cemiplimab in a trial with 200 patients at 28 cancer centres in Australia, France, Spain and the UK, including the Western General Hospital in Edinburgh.The types of cancer included in the trial are cervical, bladder, liver, non-small cell lung cancer, squamous cell carcinoma of the head and neck, and a type of bowel cancer called microsatellite stable bowel cancer.Every patient who responded in the EMITT-1 trial had already failed treatment, and most had no conventional treatment options left. Crucially, immunotherapy hadn't worked – or had stopped working.Unlike many cancer treatments, the pill – which has been developed by Oxford-based company Greywolf Therapeutics and can be taken at home – was well tolerated by patients meaning that they could stay on the drug and have a better quality of life.The results, generated between March 2023 and March 2026, were presented at this year’s American Society of Clinical Oncology (ASCO) meeting in Chicago. Early results Responses where the tumour has shrunk by at least 30% were achieved across all six tumour types, and deep responses of up to 95% were observed.The combination was most effective in the cohort of patients with bladder cancer and, critically, showed promise in those with microsatellite stable (MSS) colorectal cancer who did not have liver metastases - a tumour type where immunotherapy has shown no meaningful benefit and remains unlicensed.Responding to immunotherapy after having already failed it before is very rare, but the overall response rate observed across the six tumour types was between 13% and 36%.Durable clinical benefit – where the patient is living without disease progression for at least six months – ranged from 18% to 55%.In a striking difference to many experimental cancer treatments, this new drug is well tolerated with a favourable safety profile across all six cancers. How it works GRWD5769 supports immunotherapy by making hidden tumour cells visible to the T cells – the cells of the immune system that attack infections – and periodically changing which T cells attack to prevent them from burning out.It does this by inhibiting an enzyme called endoplasmic reticulum aminopeptidase 1 (ERAP1), which helps the immune system to recognise the cancer and attack it.When used in combination with cemiplimab – used to block a protein called PD-1 which stops the immune system from fighting tumours – this creates a two-pronged approach to attacking the cancer. Immunotherapy has been a gamechanger in the way we treat cancer, but the number of people that can benefit is still relatively low. What excites me about this trial is the combination of what we’re seeing - strong signals of efficacy across six tumour types that have shown great resistance to immunotherapy, with very few side effects. That's unusual at such an early stage when we’re usually just looking at how safe it is. There’s a lot more work to be done before it reaches the clinic, but for a brand-new drug to show that kind of profile so early, and in so many different types of hard-to-treat cancers, gives me genuine optimism. Professor Fiona Thistlethwaite Consultant Medical Oncologist at The Christie NHS Foundation Trust and Principal Investigator of the trial This exciting new type of immunotherapy reveals hidden aspects of the cancer to the immune system to renew the immune response and then keep it refreshed and active. It is fantastic to have been able to bring this promising new immunotherapy approach through to clinical trials and to see our patients benefiting. Professor Stefan Symeonides Professor of Experimental Cancer Medicine at the Institute of Genetics and Cancer Patient story Pat Brogan, a 68-year-old grandfather from Cowdenbeath in Fife, was diagnosed with stage 4 lung cancer in 2021. A course of chemotherapy and immunotherapy worked for around three years before his tumours started to grow again.After starting on the EMITT-1 trial in February 2025, he has seen his advanced lung cancer shrink by around 30% and is getting ready to walk his daughter down the aisle and go on holiday to Spain with his wife Linda. I’m so grateful to Professor Stefan Symeonides and his team in Edinburgh and to all the other patients who have taken part in cancer research before me. I wouldn’t have the life I have now without them. Hopefully, by taking part in research, I can also make things better for people like me in the future. The trial is still ongoing, with a larger study already in planning. Related links Stefan Symeonides Research Group The Christie Tags 2026 This article was published on Tuesday 2 June 2026
