Combination immunotherapy significantly improved disease-free survival after surgery in patients with primary renal cell carcinoma (RCC), according to results from the phase III RAMPART trial. These findings were presented at the European Society for Medical Oncology (ESMO) Congress 2025 by James Larkin, PhD, Professor in the Division of Clinical Studies at The Institute of Cancer Research, London, and a consultant medical oncologist at The Royal Marsden NHS Foundation Trust (Abstract LBA93).
RAMPART Design
These results are the first reported data from RAMPART, a trial designed to assess whether immunotherapy can prevent recurrence of disease in patients with early-stage kidney cancer who have undergone surgery with the aim of a cure. The trial investigated whether treatment with the PD-L1 inhibitor durvalumab alone or in combination with the CTLA-4 inhibitor tremelimumab after surgery could prevent recurrence of renal cell carcinoma (RCC).
The study involved 790 patients recruited across 80 sites worldwide between October 2018 and June 2023 and was led by the Medical Research Council (MRC) Clinical Trials Unit at University College London (MRC CTU at UCL).
Using durvalumab and tremelimumab together may produce a stronger immune response by blocking two different checkpoints, researchers hypothesized. Together, they may increase the number of T cells and prolong their activity at the tumor site, leading to a stronger and more sustained antitumor immune response.
Patients were randomly assigned to one of three groups: active monitoring following surgery; durvalumab alone for 1 year; or durvalumab plus tremelimumab, with the combination given during the first two cycles alone. Results comparing the durvalumab alone arm of the trial with active monitoring are expected in the future.
Key Results
At 3 years, the disease-free survival rate was 81% in the group receiving durvalumab and tremelimumab, compared with 73% in the active monitoring group, who were on no active treatment but regularly monitored.
The greatest benefit was observed among the group of patients at higher risk of relapse. In this subgroup, the 3-year disease-free survival rate was 78% with combination treatment vs 61% with active monitoring. The patients were deemed to be at high risk of disease recurrence based on several different factors, such as the stage of the cancer at diagnosis, whether the cancer had spread to nearby lymph nodes, and/or the size of the primary tumor.
Safety findings were consistent with the known profiles of durvalumab and tremelimumab and other immune checkpoint inhibitors.
Dr. Larkin, who was the chief investigator of the RAMPART study, said: “In a subgroup of patients facing a high risk of cancer returning after surgery, we saw a remarkable result, with over a 43% relative reduction in the risk of recurrence. These are very promising findings that confirm the benefit of immunotherapy in the treatment of high-risk RCC.”
Angela Meade, DPhil, one of the leads of the international RAMPART trial who is based at the MRC Clinical Trials Unit at UCL, said: “We are very pleased to see that this combination of immunotherapy drugs significantly reduces the risk of kidney cancer returning. Importantly, the greatest benefit was observed in participants who were at the highest risk of recurrence. As these treatments can cause serious side effects, it is important that we target their use to those most likely to benefit.”
Disclosure: The RAMPART trial was sponsored by UCL. This study was conducted with financial support from AstraZeneca UK Limited. For full disclosures of the study authors, visit cslide.ctimeetingtech.com.
