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Updated: Jun 8, 2025
Development of a 68Gallium-Labeled D-Peptide PET Tracer for Imaging Programmed Death-Ligand 1 Expression
Published on: February 3, 2023
Current and Future Perspectives of PDL1 PET and SPECT Imaging
Indraja D Dev1, Ameya D Puranik2, Baljinder Singh3
1Assistant Professor, Department of Nuclear Medicine and Molecular Imaging, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Center, Homi Bhabha National Institute, Mumbai, India.
Abstract:
Programmed Death 1 (PD1) and Programmed Death Ligand (PDL1) play a crucial role in tumor microenvironment by helping cancer cells evade innate immunity. Numerous inhibitor anticancer drugs targeting this interplay have been used in clinical practice and many more are in preclinical stage. These drugs have shown promising results in achieving good response and long-term clinical benefit, is routinely performed to identify patients who may benefit. However, there are major challenges associated with these immunohistochemistry tests which have opened the space for noninvasive imaging modalities using PD1 and PDL1 inhibitors labeled with either PET or SPECT radionuclides. These radiopharmaceuticals, although primarily developed for the field of immunotherapy, have great potential in expanding and optimizing the combination of radiopharmaceutical therapies with PD1-PDL1 targeting anticancer drugs. This review elaborates currently available PET and SPECT radiopharmaceuticals targeting PD1-PDL1 axis. It also explores the potential future role of newer targets which are being developed and tested in various preclinical studies.
Insights
Noninvasive imaging using radiolabeled Programmed Death 1 (PD1) and Programmed Death Ligand (PDL1) inhibitors offers a promising alternative to current tests. This approach may optimize immunotherapy combinations and expand radiopharmaceutical therapy applications.
Area of Science:
- Oncology
- Immunology
- Radiochemistry
Background:
- Programmed Death 1 (PD1) and Programmed Death Ligand (PDL1) are key in tumor immune evasion.
- Targeted inhibitors show promise in cancer treatment but face diagnostic challenges.
- Immunohistochemistry tests for patient selection have limitations.
Purpose of the Study:
- To review current PET and SPECT radiopharmaceuticals targeting the PD1-PDL1 axis.
- To explore the potential of these imaging modalities in immunotherapy.
- To discuss future targets in PD1-PDL1 research.
Main Methods:
- Review of existing literature on PET and SPECT radiopharmaceuticals for PD1-PDL1.
- Analysis of their role in immunotherapy and radiopharmaceutical therapy combinations.
- Exploration of emerging preclinical targets.
Main Results:
- Several PET and SPECT radiopharmaceuticals targeting the PD1-PDL1 axis are available.
- These radiopharmaceuticals have potential for noninvasive patient selection and treatment optimization.
- Newer targets are under investigation in preclinical studies.
Conclusions:
- Noninvasive imaging with radiolabeled PD1/PDL1 inhibitors presents an alternative to immunohistochemistry.
- Radiopharmaceuticals can enhance immunotherapy and radiopharmaceutical therapy combinations.
- Future research focuses on novel targets for improved cancer treatment.
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