[186Re]-labeled mouse and chimeric monoclonal antibody 323/A3: A comparison of the efficacy in experimental human ovarian cancer

Els Kievit, Frank B. Van Gog, Hennie M.M. Schlüper, Guus A.M.S. Van Dongen, Herbert M. Pinedo, Epie Boven*

*Corresponding author for this work

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We have investigated whether [186-Re]-labeled chimeric monoclonal antibody 323/A3 (MAb c-323/A3) is as effective as [186Re]-labeled mouse 323/A3 (m-323/A3) in the growth inhibition of human ovarian cancer xenografts OVCAR-3 and FMa. [186Re] was conjugated to MAbs with the use of the chelate S-benzoylmercaptoacetyltriglycine (S-benzoyl-MAG3). The maximum number of metal-MAG3 groups that could be conjugated to one MAb molecule accepting a minimal initial increase of the blood clearance (15%) was 8.5 and 2.9 for c-323/A3 and m-323/A3, respectively. With these molar ratios the immunoreactivity of both MAbs was maintained. An inverse relationship was observed between the protein dose of c-323/A3 and its blood clearance. Both [186Re]-c-323/A3 and [186Re]-m-323/A3 were comparable in the inhibition of the tumor growth when higher protein doses were used. Together with the expected lower immunogenicity, our results imply that c-323/A3 is preferable for use in [186Re]-radioimmunotherapy in ovarian cancer patients.

Original languageEnglish
Pages (from-to)37-45
Number of pages9
JournalNuclear Medicine and Biology
Issue number1
Publication statusPublished - 1 Jan 1998

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