Source: Peplau, E., De Rose, F., Eichinger, A. et al. Effective rational humanization of a PASylated anti-galectin-3 Fab for the sensitive PET imaging of thyroid cancer in vivo. Sci Rep 11, 7358 (2021).

High contrast in vivo tumor imaging

In vivo imaging using radiolabeled agents is a powerful, sensitive and non-invasive method to diagnose cancer and to assist surgery and radiotherapy. However, choosing the right molecule format can be challenging. Full-length antibody tracers often show a poor tumor penetration and persistent circulation, resulting in a high background. Short-acting tracers like peptides or antibody fragments improve the tumor to blood ratio, but due to a rapid clearance from the body the time for efficient tumor enrichment is too short. PASylation® enables tracer engineering to reach optimal conditions for high tumor uptake and excellent PET/SPECT imaging contrast.

  • Tunable circulation time

    • Plasma half-life can be tailored to optimize imaging contrast
  • High tumor to blood ratio

    • PASylation boosts tumor uptake of the tracer
  • No accumulation in healthy tissue

    • PAS sequences are inert: no unspecific enrichment in healthy tissue
  • No Fc region

    • No FcγR mediated cellular uptake
    • No undesired longterm circulation via endosomal recycling
  • Related publications

    Richter A., Knorr K., Schlapschy M., Robu S., Morath V., Mendler C., Yen H., Steiger K., Kiechle M., Weber W., Skerra A., Schwaiger M. (2020) First in-human medical imaging with a PASylated 89Zr-labeled anti-HER2 Fab-fragment in a patient with metastatic breast cancer. Nucl. Med. Mol. Imaging 54, 114–119.

  • Peplau, E., De Rose, F., Eichinger, A., Reder S., Mittelhäuser M., Scafetta G., Schwaiger M., Weber W.A., Bartolazzi A., D’Alessandria C., Skerra A. (2021) Effective rational humanization of a PASylated anti-galectin-3 Fab for the sensitive PET imaging of thyroid cancer in vivo. Sci. Rep. 11, 7358.

  • Deuschle F.C., Morath V., Schiefner A., Brandt C., Ballke S., Reder S., Steiger K., Schwaiger M., Weber W., Skerra A.(2020) Development of a high affinity Anticalin® directed against human CD98hc for theranostic applications. Theranostics 10, 2172-2187.

  • Mendler C. T., Feuchtinger A., Heid I., Aichler M., D’Alessandria C., Pirsig S., Blechert B., Wester H. J., Braren R., Walch A., Skerra A., Schwaiger M. (2016) Tumor uptake of anti-CD20 Fabs depends on tumor perfusion. J. Nucl. Med. 57, 1971-1977.

  • Mendler C. T., Friedrich L., Laitinen I., Schlapschy M., Schwaiger M., Wester H.J., Skerra A. (2015) High contrast tumor imaging with radio-labeled antibody Fab fragments tailored for optimized pharmacokinetics via PASylation. MAbs 7, 96-109.

  • Mendler C. T., Gehring T., Schwaiger M., Wester H.J., Skerra A. (2015) 89Zr-labeled versus 124I-labeled αHER2 Fab with optimized plasma half-life for high-contrast tumor imaging in vivo. J. Nucl. Med. 56, 1112-1118.