Clinical Application of CAIX-Targeted PET Imaging in Tumors

Summary

According to the 2020 global cancer statistics, renal carcinoma ranks as the fourteenth most common malignant tumor worldwide. In 2020, there were 431,288 new cases and 179,368 deaths from renal cancer, and both the incidence and mortality rates are projected to continue rising by 2025. Early non-invasive diagnosis of clear cell renal cell carcinoma (ccRCC) is crucial for improving prognosis. Nuclear medicine molecular imaging offers the advantages of real-time, dynamic, and non-invasive detection of lesions throughout the body. However, there is currently a lack of highly efficient and targeted molecular probes for early and accurate diagnosis of this tumor in clinical practice.

The high expression of CAIX plays a central role in the pathogenesis of renal cancer by altering cellular metabolism, inducing angiogenesis, promoting epithelial-mesenchymal transition (EMT), invasion, and metastatic spread. CAIX is highly expressed in 95% of ccRCC cases. In fact, CAIX expression levels have been reported as an independent predictor of survival in advanced ccRCC. Moreover, CAIX expression in normal tissues is limited, primarily restricted to the stomach, the basolateral aspects of proliferating small intestinal crypt epithelial cells, and the gallbladder. Therefore, the differential expression of CAIX between ccRCC tumors and normal tissues highlights its potential as a robust target for nuclear medicine molecular probe research and development in ccRCC.

This study utilized high-throughput screening to identify small molecules with high affinity for CAIX. These molecules were subsequently cyclized and modified to enhance their in vivo stability. A bifunctional chelator, H3RESCA, was introduced at the C-terminus to construct the small-molecule compound RESCA-CAIX-LT. PET probes were prepared by radiolabeling with 68Ga or 18F, and their diagnostic efficacy for renal cancer was investigated. Small-animal PET imaging initially demonstrated that the probe exhibits high affinity and excellent imaging performance. The modifications also altered the in vivo metabolic profile of the original design, reducing non-specific uptake in organs such as the stomach, small intestine, and gallbladder. Furthermore, toxicological experiments confirmed the probe's high safety profile and in vivo stability.

Conditions

• Kidney Cancers

Interventions

DRUG

Each patient will undergo 68Ga/18F-CAIX-LT-BCH PET/CT imaging, with an administered radioactive dose of approximately 0.05-0.1 mCi/kg.

68Ga/18F-CAIX-LT-BCH (0.05-0.1 mCi/kg) is intravenously administered, followed immediately by whole-body dynamic imaging using the United Imaging uEXPLORER total-body PET/CT system. If indeterminate lesions are observed on routine imaging, delayed imaging may be performed for further evaluation. The patient is positioned supine and instructed to breathe quietly. The acquired data are reconstructed using the Ordered Subset Expectation Maximization (OSEM) algorithm to generate dynamic PET image frames. Static PET/CT or PET/MRI Protocol: Following intravenous administration of the quality-controlled 68Ga/18F-CAIX-LT-BCH (0.05-0.1 mCi/kg), the patient rests for 50-60 minutes before undergoing whole-body or regional static scanning. The patient is positioned supine and maintains quiet breathing. Image data are reconstructed using the OSEM algorithm to produce dynamic PET image frames.

Sponsors & Collaborators

• Peking University Cancer Hospital & Institute

  lead OTHER

Study Design

Allocation

NA

Purpose

DIAGNOSTIC

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-03-01

Primary Completion

2026-12-31

Completion

2026-12-31

Countries

• China

Study Locations