RT Journal Article
SR Electronic
T1 (2<em>S</em>)-2-(3-(1-Carboxy-5-(4-<sup>211</sup>At-Astatobenzamido)Pentyl)Ureido)-Pentanedioic Acid for PSMA-Targeted α-Particle Radiopharmaceutical Therapy
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1569
OP 1575
DO 10.2967/jnumed.116.174300
VO 57
IS 10
A1 Kiess, Ana P.
A1 Minn, Il
A1 Vaidyanathan, Ganesan
A1 Hobbs, Robert F.
A1 Josefsson, Anders
A1 Shen, Colette
A1 Brummet, Mary
A1 Chen, Ying
A1 Choi, Jaeyeon
A1 Koumarianou, Eftychia
A1 Baidoo, Kwamena
A1 Brechbiel, Martin W.
A1 Mease, Ronnie C.
A1 Sgouros, George
A1 Zalutsky, Michael R.
A1 Pomper, Martin G.
YR 2016
UL http://jnm.snmjournals.org/content/57/10/1569.abstract
AB Alpha-particle emitters have a high linear energy transfer and short range, offering the potential for treating micrometastases while sparing normal tissues. We developed a urea-based, 211At-labeled small molecule targeting prostate-specific membrane antigen (PSMA) for the treatment of micrometastases due to prostate cancer (PC). Methods: PSMA-targeted (2S)-2-(3-(1-carboxy-5-(4-211At-astatobenzamido)pentyl)ureido)-pentanedioic acid (211At-6) was synthesized. Cellular uptake and clonogenic survival were tested in PSMA-positive (PSMA+) PC3 PIP and PSMA-negative (PSMA−) PC3 flu human PC cells after 211At-6 treatment. The antitumor efficacy of 211At-6 was evaluated in mice bearing PSMA+ PC3 PIP and PSMA– PC3 flu flank xenografts at a 740-kBq dose and in mice bearing PSMA+, luciferase-expressing PC3-ML micrometastases. Biodistribution was determined in mice bearing PSMA+ PC3 PIP and PSMA– PC3 flu flank xenografts. Suborgan distribution was evaluated using α-camera images, and microscale dosimetry was modeled. Long-term toxicity was assessed in mice for 12 mo. Results: 211At-6 treatment resulted in PSMA-specific cellular uptake and decreased clonogenic survival in PSMA+ PC3 PIP cells and caused significant tumor growth delay in PSMA+ PC3 PIP flank tumors. Significantly improved survival was achieved in the newly developed PSMA+ micrometastatic PC model. Biodistribution showed uptake of 211At-6 in PSMA+ PC3 PIP tumors and in kidneys. Microscale kidney dosimetry based on α-camera images and a nephron model revealed hot spots in the proximal renal tubules. Long-term toxicity studies confirmed that the dose-limiting toxicity was late radiation nephropathy. Conclusion: PSMA-targeted 211At-6 α-particle radiotherapy yielded significantly improved survival in mice bearing PC micrometastases after systemic administration. 211At-6 also showed uptake in renal proximal tubules resulting in late nephrotoxicity, highlighting the importance of long-term toxicity studies and microscale dosimetry.