ImmunoPET Imaging of Pancreatic Cancer

Pancreatic cancer remains one of the most aggressive cancer types. Target-specific targeted therapy is an attractive therapeutic alternative for the treatment of patients with a wide range of cancers, including pancreatic cancer. Companion diagnostic technique is critical for the success of targeted therapies. SHR-A1921 is a TROP2-directed antibody-drug-conjugate (ADC) approved for several clinical trials for advanced solid tumors. SHR1920 is the humanized anti-Trop2 monoclonal antibody (hIgG1) of SHR-A1921. Radio-labeling SHR1920 with radionuclide Zirconium-89 (89Zr) enables non-invasive imaging and quantification of SHR-A1921 distribution in cancer patients. Performing a \[89Zr\]Zr-DFO-SHR1920 PET scan before treatment with SHR-A1921 can evaluate tracer uptake in the primary and metastatic tumor lesions and normal organ distribution. CLND18.2 is another potential therapeutic target for pancreatic cancer. Target-specific immunoPET imaging may help identify patients more likely to benefit from targeted therapy.

Enrolled patients with pancreatic cancer will undergo whole-body \[89Zr\]Zr-DFO-SHR1920 immunoPET/CT scans at 0,1, 3, 5, or 7 days after tracer injection (1-3 mCi). Uptake of \[89Zr\]Zr-DFO-SHR1920 in tumor and normal organs/tissues will be scored visually and quantitatively. For immunoPET imaging with 18F or 68Ga-labeled 3A12 (a nanobody targeting CLDN18.2), immunoPET/CT scan will be performed 1h after tracer injection (0.05-0.1 mCi/kg). Tumor uptake will be quantified by the maximum standard uptake value (SUVmax). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy will be calculated to evaluate the diagnostic efficacy. The correlation between lesion uptake and protein expression level determined by immunohistochemistry staining will be further analyzed. The exploration endpoint will be the imaging feasibility and preliminary diagnostic value of the above tracers.