(UroToday.com) The 2026 European Association of Urology (EAU) annual meeting featured an advancement in diagnosis and prognosis, and personalized treatment for renal cell carcinoma (RCC) session, and a presentation by Dr. Tonghu Liu discussing the development of a novel 68Ga-labeled radiotracer targeting CA IX for the diagnosis of clear cell RCC. CA IX is widely overexpressed in clear cell RCC, making it a promising molecular imaging target. This study, presented at EAU 2026, aimed to evaluate the diagnostic efficacy of 68Ga-C1, a novel bicyclic peptide PET tracer targeting CAIX, in preclinical models and patients with clear cell RCC.
The CAIX targeting radiotracer 68Ga-C1 was developed and validated through in vitro assays. Initially, the investigators performed preclinical evaluations of 68Ga-C1 in clear cell RCC cell lines and xenograft mouse models. Subsequently, they performed the translational study in patients with suspected RCC and in clear cell RCC patients for restaging:
In the preclinical study, 68Ga-C1 showed high affinity to CAIX, specific uptake in CAIX-positive cell lines and xenograft mouse models, suitable pharmacokinetic and safety profiles:
In the translational study, five patients with newly detected renal mass and seven clear cell RCC patients with suspected recurrence or metastasis after partial or complete nephrectomy were enrolled. Ten clear cell RCC patients and one patient with angiosarcoma showed positive CAIX expression and high uptake of 68Ga-C1, while one patient confirmed pathologically as non-clear cell RCC showed negative uptake of 68Ga-C1. The following figure compares metastatic lesion detection using 68Ga-C1 and 18F-FDG PET/CT:
Dr. Liu concluded this presentation discussing the development of a novel 68Ga-labeled radiotracer targeting CA IX for the diagnosis of clear cell RCC with the following take-home points:
- 68Ga-C1 is an effective CAIX imaging radiotracer
- 68Ga-C1’s superior imaging properties make it a valuable tool for non-invasively evaluating the clear cell RCC of various types of RCC with high specificity
Presented by: Tonghu Liu, Peking University First Hospital, Beijing, China
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2026 European Association of Urology (EAU) Annual Meeting, London, United Kingdom, Fri, Mar 13 – Mon, Mar 16, 2026.