Affibody-Mediated PNA-Based Pretargeted Cotreatment Improves Survival of Trastuzumab-Treated Mice Bearing HER2-Expressing Xenografts

The Journal of Nuclear Medicine

article

Maryam Oroujeni¹  Hanna Tano²  Anzhelika Vorobyeva¹  Yongsheng Liu¹  Olga Vorontsova¹  Tianqi Xu¹  Kristina Westerlund²  Anna Orlova³  Vladimir Tolmachev¹  Amelie Eriksson Karlström² 

[1] Department of Immunology, Genetics, and Pathology, Uppsala University;Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology, and Health, KTH Royal Institute of Technology, AlbaNova University Center;Research Centrum for Oncotheranostics, Research School of Chemistry and Applied Biomedical Sciences, Tomsk Polytechnic University;Department of Medicinal Chemistry, Uppsala University, Uppsala University

关键词: trastuzumab;    PNA pretargeting;    Affibody molecules;    radionuclide therapy;    HER2;   

DOI  :  10.2967/jnumed.121.262123

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Treatment of patients with human epidermal growth factor receptor 2 (HER2)–expressing tumors using the monoclonal antibody trastuzumab increases survival. The Affibody-based peptide nucleic acid (PNA)–mediated pretargeted radionuclide therapy has demonstrated efficacy against HER2-expressing xenografts in mice. Structural studies suggest that Affibody molecules and trastuzumab bind to different epitopes on HER2. The aim of this study was to test the hypothesis that a combination of PNA-mediated pretargeted radionuclide therapy and trastuzumab treatment of HER2-expressing xenografts can extend survival compared with monotherapies. Methods: Mutual interference of the primary pretargeting probe ZHER2:342-SR-HP1 and trastuzumab in binding to HER2-expressing cell lines was investigated in vitro. Experimental therapy evaluated the survival of mice bearing HER2-expressing SKOV-3 xenografts after treatment with vehicle, trastuzumab only, pretargeting using Affibody-PNA chimera ZHER2:342-SR-HP1 and complementary probe 177Lu-HP2, and combination of trastuzumab and pretargeting. The ethical permit limited the study to 90 d. The animals’ weights were monitored during the study. After study termination, samples of liver and kidneys were evaluated by a veterinary pathologist for toxicity signs. Results: The presence of a large molar excess of trastuzumab had no influence on the affinity of ZHER2:342-SR-HP1 binding to HER2-expressing cells in vitro. The affinity of trastuzumab was not affected by a large excess of ZHER2:342-SR-HP1. The median survival of mice treated with trastuzumab (75.5 d) was significantly longer than the survival of mice treated with a vehicle (59.5 d). Median survival of mice treated with pretargeting was not reached by day 90. Six mice of 10 in this group survived, and 2 had complete remission. All mice in the combination treatment group survived, and tumors in 7 mice had disappeared at study termination. There was no significant difference between animal weights in the different treatment groups. No significant pathologic alterations were detected in livers and kidneys of treated animals. Conclusion: Treatment of mice bearing HER2-expressing xenografts with the combination of trastuzumab and Affibody-mediated PNA-based radionuclide pretargeting significantly increased survival compared with monotherapies. Cotreatment was not toxic for normal tissues.

【 授权许可】

CC BY