Whole-body Programmed Death-Ligand 1 Expression Imaging
Match PD-1/PD-L1 checkpoint inhibitor therapies to the right patients

Immunotherapies based on checkpoint blockade of PD-1/PD-L1 checkpoint showed effectiveness in some patients with several tumor types. However, identifying patients likely to benefit the most from PD-1/PD-L1 checkpoint inhibitor therapies remains clinically challenging. Immunohistochemistry (IHC) has been the only FDA approved diagnostic test to assess tumor PD-L1 expression and thus choose patients for PD-1/PD-L1 Inhibitor therapies.

However, IHC procedure requires invasive biopsy and is unable to reflect the heterogeneous nature of PD-L1 expression in the primary tumor site as well as variability in its expression between primary and metastatic tumor sites. Moreover, this biopsy-required clinical procedure does not provide tumor PD-L1 expression status in real-time. Given the risks involved in invasive procedures and the potential for misleading results from the ex-vivo methods, innovative non-invasive alternatives that can provide whole-body PD-L1 status in real time are needed in clinical practice.
The first-in-human study that tested a PD-L1 specific radiotracer showed that clinical responses were better correlated with pretreatment PET signal than with IHC. The study was conducted in Netherlands and results were published on Nature Medicine in December 2018. In this study, the PD-L1 specific radiotracer uptake appeared to be a strong predictor of response to PD-L1 inhibitor treatment. [Bensch, Frederike, et al. Nature medicine 2018 ]

The first single-domain antibody radioimaging tracer for whole-body PD-L1 expression imaging
  • High affinity and specificity
  • Discriminates PD-L1 positive and negative tumor cells
  • Binds at a different epitope on the PD-L1 receptor than PD-L1 inhibitors
  • Best imaging time between 1-2 hours

We are planning clinical studies and looking for interested parties for collaborations.