{Reference Type}: Journal Article
{Title}: In vivo stable 211At-labeled prostate-specific membrane antigen-targeted tracer using a neopentyl glycol structure.
{Author}: Suzuki H;Kannaka K;Hirayama M;Yamashita T;Kaizuka Y;Kobayashi R;Yasuda T;Takahashi K;Uehara T;
{Journal}: EJNMMI Radiopharm Chem
{Volume}: 9
{Issue}: 1
{Year}: 2024 Jun 17
暂无{DOI}: 10.1186/s41181-024-00278-8
{Abstract}: <B>BACKGROUND: </B>Prostate cancer is a common cancer among men worldwide that has a very poor prognosis, especially when it progresses to metastatic castration-resistant prostate cancer (mCRPC). Therefore, novel therapeutic agents for mCRPC are urgently required. Because prostate-specific membrane antigen (PSMA) is overexpressed in mCRPC, targeted alpha therapy (TAT) for PSMA is a promising treatment for mCRPC. Astatine-211 (211At) is a versatile α-emitting radionuclide that can be produced using a cyclotron. Therefore, 211At-labeled PSMA compounds could be useful for TAT; however, 211At-labeled compounds are unstable against deastatination in vivo. In this study, to develop in vivo stable 211At-labeled PSMA derivatives, we designed and synthesized 211At-labeled PSMA derivatives using a neopentyl glycol (NpG) structure that can stably retain 211At in vivo. We also evaluated their biodistribution in normal and tumor-bearing mice.<BR><B>RESULTS: </B>We designed and synthesized 211At-labeled PSMA derivatives containing two glutamic acid (Glu) linkers between the NpG structure and asymmetric urea (NpG-L-PSMA ((L-Glu)2 linker used) and NpG-D-PSMA ((D-Glu)2 linker used)). First, we evaluated the characteristics of 125I-labeled NpG derivatives because 125I was readily available. [125I]I-NpG-L-PSMA and [125I]I-NpG-D-PSMA showed low accumulation in the stomach and thyroid, indicating their high in vivo stability against deiodination. [125I]I-NpG-L-PSMA was excreted in urine as hydrophilic radiometabolites in addition to the intact form. Meanwhile, [125I]I-NpG-D-PSMA was excreted in urine in an intact form. In both cases, no radioactivity was observed in the free iodine fraction. [125I]I-NpG-D-PSMA showed higher tumor accumulation than [125I]I-NpG-L-PSMA. We then developed 211At-labeled PSMA using the NpG-D-PSMA structure. [211At]At-NpG-D-PSMA showed low accumulation in the stomach and thyroid in normal mice, indicating its high stability against deastatination in vivo. Moreover, [211At]At-NpG-D-PSMA showed high accumulation in tumor similar to that of [125I]I-NpG-D-PSMA.<BR><B>CONCLUSIONS: </B>[211At]At-NpG-D-PSMA showed high in vivo stability against deastatination and high tumor accumulation. [211At]At-NpG-D-PSMA should be considered as a potential new TAT for mCRPC.