Kidney injury molecule 1 (KIM-1) is a promising biomarker in adjuvant clear cell renal cell carcinoma (ccRCC), but its relevance in advanced ccRCC or papillary RCC (pRCC) remains unclear. CALYPSO (NCT02819596) was a prospective, multi-arm trial that evaluated durvalumab alone or in combination with tremelimumab or savolitinib in metastatic ccRCC and pRCC. Circulating KIM-1 levels were measured at baseline and on-treatment. The primary endpoint was to explore if KIM-1 levels were raised in pRCC. Analyses were exploratory and p values were nominal. KIM-1 was measured in 123 patients with ccRCC and 31 patients with pRCC. Higher median concentrations occurred in pRCC compared to ccRCC (7835 vs 5470 pg/ml, p = 0.05). Reductions in KIM-1 levels occurred with systemic therapy in both ccRCC and pRCC (-59.2% and -32% respectively). In pRCC, radiological responders had significantly lower baseline KIM-1 levels (p = 0.025). In ccRCC, high baseline KIM-1 levels were associated with significantly shorter overall survival (OS) (hazard ratio [HR] 1.77; 95% CI, 1.15-2.72; p = 0.01). Also, an increase in KIM-1 during therapy was linked to worse progression-free survival (HR 1.7; 95% CI, 1.13-2.58; p = 0.01) and OS (HR 1.95; 95% CI, 1.23-3.08; p = 0.004) in ccRCC. This exploratory analysis supports the utility of KIM-1 in advanced ccRCC and pRCC.
European urology. 2026 Apr 02 [Epub ahead of print]
Sara Coca Membribes, Wenxin Xu, Cristina Suárez, Poulam M Patel, James Larkin, Begoña P Valderrama, Charles Mein, Charlotte Ackermann, Thomas Powles
Barts Cancer Centre Biomedical Research Centre/CRUK ECMC, Queen Mary University of London, London, UK. Electronic address: ., Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA., Vall d'Hebron University Hospital and Institute of Oncology, Universitat Autonoma de Barcelona, Barcelona, Spain., Nottingham University Hospitals NHS Trust, Nottingham, UK; Royal Marsden Hospital NHS Foundation Trust, London, UK., Royal Marsden Hospital NHS Foundation Trust, London UK., University Hospital Virgen del Rocío, Sevilla, Spain., Genome Centre, Faculty of Medicine and Dentistry, Queen Mary University of London, United Kingdom., Barts Cancer Centre Biomedical Research Centre/CRUK ECMC, Queen Mary University of London, London, UK., Barts Cancer Centre Biomedical Research Centre/CRUK ECMC, Queen Mary University of London, London, UK. Electronic address: .