Brown I, Mitchell JS. The development of a [211At]-astatinated endoradiotherapeutic drug: Part II. Therapeutic results for transplanted adenocarcinoma of the rectum in mice and associated studies.
Int J Radiat Oncol Biol Phys 1994;
29:115-24. [PMID:
8175418 DOI:
10.1016/0360-3016(94)90233-x]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE
6-[211At]-astato-MNDP is of a class of a high linear energy transfer endoradiotherapeutic drug, which selectively targets to an onco-APase isoenzyme expressed by certain epithelial and germ cell tumors. The therapeutic efficacy and acute toxicity of its endogenous alpha-particle emissions have been studied in a murine tumor model.
METHODS AND MATERIALS
211At was produced by the 207Bi(alpha,2n)211 At cyclotron-based nuclear reaction. High specific activity 6-[211At]-astato-MNDP was rapidly synthesized by in vacuo thermal heterogeneous isotopic exchange. The therapeutic potential of 6-[211At]-astato-MNDP and 211At- was determined in mice bearing a transplanted CMT-93 rectal carcinoma which exhibited onco-APase activity.
RESULTS
Significant therapeutic effects due to targeted alpha-particle emissions have been confirmed for the activity dose range, 10-750 kBq 6-[211At]-astato-MNDP. A therapeutic window has been identified, whereby cure rates of approximately 45-65% were achieved following administration of 55-300 kBq 6-[211At]-astato-MNDP. Estimated tumor absorbed radiation doses were not inconsistent with clinical response. Irreversible hematoxicity or stigmata of acute radiation damage in other critical normal tissues were not encountered. Nonspecifically internalized 211At- exerted no therapeutic effect.
CONCLUSION
Therapeutic results for 6-[211At]-astato-MNDP have confirmed the profound in vivo cytotoxicity of its targeted alpha-radiations in the CMT-93 tumor. Acute normal tissue toxicity was acceptable. A rationale for optimal fractionation of targeted 6-[211At]-astato-MNDP endoradiotherapy is discussed, and its putative role in the possible individualized management of certain human tumors has been proposed.
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