WUHAN — Researchers in Wuhan presented first-in-human results for a new PET tracer, 68Ga-RCC78, which demonstrated high sensitivity and tumor-to-background contrast in detecting clear cell renal cell carcinoma (ccRCC) at the Society of Nuclear Medicine and Molecular Imaging 2026 Annual Meeting. The tracer accurately distinguished CAIX-positive tumors from CAIX-negative cases, consistent with biopsy immunostaining, and outperformed the standard 18F-FDG in tumor uptake for CAIX-positive disease.
68Ga-RCC78 is a cyclic peptide probe targeting carbonic anhydrase IX (CAIX), a protein constitutively overexpressed in ccRCC. Unlike traditional antibody-based CAIX tracers that require days to clear the body, 68Ga-RCC78 enables rapid, high-contrast imaging. In preclinical studies, it showed high and sustained tumor uptake in CAIX-high xenografts and rapid background clearance. In a first-in-human study involving 13 ccRCC patients, the tracer identified additional metastatic lesions missed by standard imaging and reduced abdominal background noise, allowing clearer visualization of intra-abdominal disease.
The development process involved synthesizing and radiolabeling 16 novel CAIX-specific cyclic peptides with gallium-68. Cellular uptake studies were conducted in CAIX-high and CAIX-low cell lines, along with CAIX-blocked controls. PET/CT imaging, biodistribution analysis, and immunohistochemistry were performed in ccRCC xenografts and patient-derived xenograft models to validate target specificity and imaging performance.
"This research provides a more precise molecular map for kidney cancer," said Dawei Jiang, PhD, professor and deputy director of Nuclear Medicine Department at Wuhan Union Hospital. "Our new probe, 68Ga-RCC78, strikes a vital balance by minimizing background noise in the abdominal cavity while maintaining the highest possible uptake in tumors, and hopefully representing a step toward personalized radiotheranostics in ccRCC."
"We have not only developed a diagnostic tool but also hope to provide a blueprint for treatment. Currently, this same molecule is being labeled with therapeutic isotopes to deliver targeted radiation directly to cancer cells while sparing healthy organs," Jiang said. The research remains in an early phase of clinical evaluation. Efforts are underway to advance 68Ga-RCC78 into larger clinical trials, with potential access through specialized institutions within the next one to two years. Broader clinical availability will depend on future regulatory approvals.
No independent assessment was available for this report.