Development of Antibody Immuno-PET/SPECT Radiopharmaceuticals for Imaging of Oncological Disorders—An Update

Abstract

Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are molecular imaging strategies that typically use radioactively labeled ligands to selectively visualize molecular targets. The nanomolar sensitivity of PET and SPECT combined with the high specificity and affinity of monoclonal antibodies have shown great potential in oncology imaging. Over the past decades a wide range of radio-isotopes have been developed into immuno-SPECT/PET imaging agents, made possible by novel conjugation strategies (e.g., site-specific labeling, click chemistry) and optimization and development of novel radiochemistry procedures. In addition, new strategies such as pretargeting and the use of antibody fragments have entered the field of immuno-PET/SPECT expanding the range of imaging applications. Non-invasive imaging techniques revealing tumor antigen biodistribution, expression and heterogeneity have the potential to contribute to disease diagnosis, therapy selection, patient stratification and therapy response prediction achieving personalized treatments for each patient and therefore assisting in clinical decision making.

Diagnosis of Pancreatic Ductal Adenocarcinoma by Immuno-Positron Emission Tomography

“…Liquid biopsies and other analysis detecting tumoral biomarkers in the body fluids are transforming cancer diagnosis and patient monitoring. Novel quantitative, specific, and sensitive imaging methods, such as immuno-PET, will be required to localize the lesion and guide successive therapeutic decisions [ 97 , 98 ].…”

“…This increased exposure was often balanced in practice since SPECT tracers required higher injected activities due to the lower detector sensitivity [ 95 , 96 ]. It is expected that the progressive increase of novel detectors and improved system designs will increase sensitivity, enabling the administration of lower administered activities facilitating the immuno-PET/SPECT use in the near future [ 97 ].…”

“…Immuno-PET will be complementary to liquid biopsies. While liquid biopsies can also identify patients with treatment failure or relapse, subsequent imaging is frequently required to localize and characterize the disease and guide subsequent treatment decisions [ 97 , 98 , 99 , 100 ].…”

Targeting the PD-1 Axis with Pembrolizumab for Recurrent or Metastatic Cancer of the Uterine Cervix: A Brief Update

“…Another, barely detectable factor is the transience of PD-L1 expression due to fluctuating interferon gamma expression in the TME, which might explain the varying response rates of PD-1 targeting therapy in CC [ 56 ]. Real-time screening methods like immuno-Positron Emission Tomography (immune-PET) with radiolabeled antibodies, might better predict response to targeted (immuno)therapies [ 57 ]. This technique combines the superior sensitivity of PET imaging with the benefits of the high targeting specificity of monoclonal antibodies.…”

Pharmacological activities and potential use of bovine colostrum for peptide-based radiopharmaceuticals: A review

“…Some methods have been used to label peptides with radionuclides, including the direct introduction of radioactive atoms (direct radiolabelling) and indirect labelling using bifunctional chelating (BFC) agents (Edelmann et al 2019). In general, radiolabelling peptides using radiometals requires the use of a BFC, while labelling using iodine radionuclide can be performed directly without the use of BFC (Dewulf et al 2020). Several examples of BFC agents used for radiolabelling peptides include diethylene triamine pentaacetic acid (DTPA), 1,4,7-triazacyclononane-1,4,7-trisacetic acid (NOTA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), and 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA) (Fig.…”