Development of 177Lu-nanobodies for radioimmunotherapy of HER2-positive breast cancer: evaluation of different bifunctional chelators

Authors

  • Matthias D'Huyvetter,

    Corresponding author
    1. Radiobiology Unit, Molecular and Cellular Biology Expert Group, Belgian Nuclear Research Center (SCK•CEN), Mol, Belgium
    2. In vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Brussels, Belgium
    • Matthias D'Huyvetter, In vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Brussels, Belgium.

      E-mail: mdhuyvet@vub.ac.be

    Search for more papers by this author
  • An Aerts,

    1. Radiobiology Unit, Molecular and Cellular Biology Expert Group, Belgian Nuclear Research Center (SCK•CEN), Mol, Belgium
    Search for more papers by this author
  • Catarina Xavier,

    1. In vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Brussels, Belgium
    Search for more papers by this author
  • Ilse Vaneycken,

    1. In vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Brussels, Belgium
    Search for more papers by this author
  • Nick Devoogdt,

    1. In vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Brussels, Belgium
    Search for more papers by this author
  • Marlies Gijs,

    1. Radiobiology Unit, Molecular and Cellular Biology Expert Group, Belgian Nuclear Research Center (SCK•CEN), Mol, Belgium
    Search for more papers by this author
  • Nathalie Impens,

    1. Radiobiology Unit, Molecular and Cellular Biology Expert Group, Belgian Nuclear Research Center (SCK•CEN), Mol, Belgium
    Search for more papers by this author
  • Sarah Baatout,

    1. Radiobiology Unit, Molecular and Cellular Biology Expert Group, Belgian Nuclear Research Center (SCK•CEN), Mol, Belgium
    Search for more papers by this author
  • Bernard Ponsard,

    1. Radioisotopes and Silicon Production Unit, Belgian Reactor 2 Expert Group, Belgian Nuclear Research Center (SCK•CEN), Mol, Belgium
    Search for more papers by this author
  • Serge Muyldermans,

    1. Department of Molecular and Cellular Interactions, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
    2. Department of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussel, Belgium
    Search for more papers by this author
  • Vicky Caveliers,

    1. In vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Brussels, Belgium
    2. Department of Nuclear Medicine, UZ Brussel, Brussels, Belgium
    Search for more papers by this author
  • Tony Lahoutte

    1. In vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Brussels, Belgium
    2. Department of Nuclear Medicine, UZ Brussel, Brussels, Belgium
    Search for more papers by this author

Abstract

Nanobodies show favourable pharmacokinetic characteristics for tumor targeting, including high tumor-to-background-ratios. Labelled with a therapeutic radionuclide, nanobodies could be used as an adjuvant treatment option for HER2-overexpressing minimal residual disease. The therapeutic radionuclide Lutetium-177 is linked to the nanobody using a bifunctional chelator. The choice of the bifunctional chelator could affect the in vivo behaviour of the radiolabeled nanobody. Consequently, we compared four different bifunctional chelators - p-SCN-Bn-DOTA, DOTA-NHS-ester, CHX-A”-DTPA or 1B4M-DTPA - in order to select the optimal chemical link between Lutetium-177 and a HER2 targeting nanobody.

MS results revealed different degrees of chelator-conjugation. High stability in time was observed, together with nanomolar affinities on HER2-expressing tumor cells. Ex vivo biodistributions as well as SPECT/micro-CT analyses showed high activities in tumors expressing medium HER2 levels with low background activity except for the kidneys. The 1B4M-DTPA-coupled conjugate was further evaluated in a high HER2-expressing tumor model. Here, tumor uptake values of 5.99 ± 0.63, 5.12 ± 0.17, 2.83 ± 0.36 and 2.47 ± 0.38 %IA/g were obtained at 1, 3, 24 and 48h p.i., which coincided with exceptionally low background values, except for the kidneys, and unprecedented tumor-to-background ratios. No specific binding was observed in a HER2-negative model.

In conclusion, the in-house developed anti-HER2 nanobody 2Rs15dHIS can be successfully labeled with 177Lu using different bifunctional chelators. Both macrocyclic and acyclic chelators show high stability in time. High specific tumor uptake combined with the lowest background uptake was measured using the 1B4M-DTPA-based conjugate. Copyright © 2012 John Wiley & Sons, Ltd.

Ancillary