Results from the international Phase III RAMPART trial were presented today at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting by researchers from The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust.
The RAMPART trial was designed to assess whether immunotherapy can prevent recurrence of disease in patients with early-stage kidney cancer who have undergone surgery.
The study investigated whether treatment with durvalumab alone, or durvalumab in combination with tremelimumab, could reduce the risk of renal cell carcinoma returning following surgery, compared to active monitoring. Renal cell carcinoma is the most common type of kidney cancer.
Can immunotherapy prevent relapse?
Durvalumab and tremelimumab are immune checkpoint inhibitors, a type of immunotherapy that helps the immune system recognise and attack cancer cells.
Patients taking part in the trial were randomly assigned to one of three groups following surgery: active monitoring, durvalumab alone for one year, or durvalumab plus tremelimumab, with tremelimumab given during the first two cycles only.
The results presented today at ASCO compared patients treated with durvalumab alone against those receiving active monitoring and showed that, at three years, disease-free survival was 78 per cent compared with 72 per cent in the active monitoring group, with a 26 per cent reduction in the risk of disease recurrence, progression or death. While the findings show an improvement in disease free survival, the difference was not statistically significant.
Combination treatment shows clearer benefit
The findings build on previously reported results from the RAMPART trial, which showed that combination treatment with durvalumab and tremelimumab significantly improved disease-free survival following surgery, with 80 per cent of patients disease-free at three years and a statistically significant 35 per cent reduction in the risk of disease recurrence, progression or death.
The greatest benefit from combination treatment was observed among patients at higher risk of relapse. In this subgroup, 76 per cent of patients treated with durvalumab and tremelimumab were disease-free at three years, compared with 61 per cent with active monitoring. In patients with the highest risk of relapse, the combination of durvalumab and tremelimumab was associated with a 48 per cent relative reduction in the risk of disease recurrence, progression or death versus active monitoring.
An enhanced anti-tumour immune response
By targeting two different immune checkpoints, the drugs work together to stimulate an enhanced anti-tumour immune response. Safety findings, including the side effects and adverse events observed during the study, were consistent with the known safety profiles of durvalumab, tremelimumab and other immune checkpoint inhibitors.
Patients were classified as high risk based on factors including the stage of the cancer at diagnosis, whether the disease had spread to nearby lymph nodes and the size of the primary tumour.
The RAMPART study involved 790 patients recruited across 80 sites worldwide between October 2018 and June 2023 and was led by the UCL Innovative Clinical Trials Unit (formerly the Medical Research Council CTU).
'We saw remarkable results in patients at the greatest risk of relapse'
Professor James Larkin, Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust and Professor of Precision Cancer Therapeutics at The Institute of Cancer Research, London, and Chief Investigator of the RAMPART study, said:
“These latest findings from the RAMPART trial further strengthen the evidence that by combining immunotherapy following surgery we can significantly reduce the chance of high-risk renal cell carcinoma returning.
“We saw remarkable results in patients at the greatest risk of relapse. For these patients, this could mean a greater chance of remaining cancer-free for longer and less fear of the disease coming back.”
Professor Angela Meade, one of the leads of the international RAMPART trial who is based at the UCL Innovative Clinical Trials Unit at UCL, said:
We are very encouraged by these results, which show that combining immunotherapy drugs can significantly lower the risk of kidney cancer coming back. The benefit was strongest in patients at highest risk. Because these treatments can have serious side effects, it’s important they’re used for patients who stand to gain the most.
'Every day is a bonus and I feel very lucky'
Janet Middlehurst, 70, a retired teacher from London, was diagnosed with Stage III kidney cancer in August 2019. Following surgery to remove her kidney, she joined the RAMPART trial at The Royal Marsden NHS Foundation Trust and received combination immunotherapy treatment. She said:
“When I was diagnosed, I didn’t even know if I’d see Christmas, so every day is a bonus, and I feel very lucky.
“I’ve been in remission ever since joining the trial, so it’s amazing to be on the other side. I celebrated my 70th birthday in April and am now looking forward to my youngest son’s wedding in Rome later this summer.
“I’ve also been able to visit my eldest son in Sydney, spend precious time with my grandchildren, and I’m now working as an exam invigilator at a local high school.”
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The RAMPART trial was sponsored by UCL. This study was conducted with financial support from AstraZeneca UK Limited and Kidney Cancer UK.