Development of a Novel Method to Enhance the Therapeutic Efficacy of ²¹¹ At-Labeled Drugs -Induces cancer immunity and enhances therapeutic efficacy when combined with immune checkpoint inhibitors

A research group led by Professor Kazuma Ogawa from the Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences at Kanazawa University and Hiroaki Echigo, a fourth-year doctoral student in the Division of Pharmacy, Graduate School of Medical Sciences and JSPS Research Fellow (DC1), at Kanazawa University has developed a new method to further enhance the therapeutic effects of targeted alpha therapy (*2) using the alpha particle emitting radionuclide astatine-²¹¹ (211At) (*1).

The study confirmed that treatment with ²¹¹At-labeled RGD peptide (*3) induces cancer immunity. Furthermore, it was found that the combination of ²¹¹ At-labeled RGD peptide and immune checkpoint inhibitors (*4) enhanced the induction of cancer immunity and synergistically enhanced the therapeutic effects. These results are expected to be a major step toward realizing next-generation cancer therapies that combine targeted alpha therapy and immunotherapy.

The results of this research were published in the online edition of the European Journal of Nuclear Medicine and Molecular Imaging, an international journal published by the European Society of Nuclear Medicine, on August 6, 2025.

Figure 1: Comparison of Treatments in the Carrier Cancer Mouse

【Glossary】

*1: Astatine-211 (²¹¹At)
A radionuclide that emits alpha rays and exhibits high cytotoxicity, it is expected to have strong cancer therapeutic effects.

*2: Targeted alpha-ray therapy
A treatment method in which alpha particle emitting radionuclides are accumulated in cancer cells to kill them from inside the body. It is a highly accurate treatment with minimal side effects.

*3: RGD peptide
Peptides containing arginine-glycine-aspartic acid sequences bind αVβ3 integrin  expressed on cancer cells _? 3 for drug delivery to cancer.

*4: Immune checkpoint inhibitors
Drugs that release the brakes on the immune system and strengthen the immune response against cancer. Anti-PD-1 antibodies and anti-CTLA-4 antibodies are available.

Click here to see the press release【Japanese only】

Journal Title: European Journal of Nuclear Medicine and Molecular Imaging

Researcher Information: Kazuma Ogawa