Preclinical Development of [211At]meta- astatobenzylguanidine ([211At]MABG) as an Alpha Particle Radiopharmaceutical Therapy for Neuroblastoma.
Clin Cancer Res 2022;
28:4146-4157. [PMID:
35861867 PMCID:
PMC9475242 DOI:
10.1158/1078-0432.ccr-22-0400]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/09/2022] [Accepted: 07/19/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE
[131I]meta-iodobenzylguanidine ([131I]MIBG) is a targeted radiotherapeutic administered systemically to deliver beta particle radiation in neuroblastoma. However, relapses in the bone marrow are common. [211At]meta-astatobenzylguanidine ([211At] MABG) is an alpha particle emitter with higher biological effectiveness and short path length which effectively sterilizes microscopic residual disease. Here we investigated the safety and antitumor activity [211At]MABG in preclinical models of neuroblastoma.
EXPERIMENTAL DESIGN
We defined the maximum tolerated dose (MTD), biodistribution, and toxicity of [211At]MABG in immunodeficient mice in comparison with [131I]MIBG. We compared the antitumor efficacy of [211At]MABG with [131I]MIBG in three murine xenograft models. Finally, we explored the efficacy of [211At]MABG after tail vein xenografting designed to model disseminated neuroblastoma.
RESULTS
The MTD of [211At]MABG was 66.7 MBq/kg (1.8 mCi/kg) in CB17SC scid-/- mice and 51.8 MBq/kg (1.4 mCi/kg) in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice. Biodistribution of [211At]MABG was similar to [131I]MIBG. Long-term toxicity studies on mice administered with doses up to 41.5 MBq/kg (1.12 mCi/kg) showed the radiotherapeutic to be well tolerated. Both 66.7 MBq/kg (1.8 mCi/kg) single dose and fractionated dosing 16.6 MBq/kg/fraction (0.45 mCi/kg) × 4 over 11 days induced marked tumor regression in two of the three models studied. Survival was significantly prolonged for mice treated with 12.9 MBq/kg/fraction (0.35 mCi/kg) × 4 doses over 11 days [211At]MABG in the disseminated disease (IMR-05NET/GFP/LUC) model (P = 0.003) suggesting eradication of microscopic disease.
CONCLUSIONS
[211At]MABG has significant survival advantage in disseminated models of neuroblastoma. An alpha particle emitting radiopharmaceutical may be effective against microscopic disseminated disease, warranting clinical development.
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