Zr-BI 905677

**Zr-BI 905677** (also referred to as [⁸⁹Zr]Zr-BI 905677) is a zirconium-89 radiolabeled form of BI 905677, an investigational tri-molecular antagonistic nanobody developed by Boehringer Ingelheim. The parent compound, BI 905677, consists of two modules that bind to distinct domains of the Wnt co-receptors LRP5 and LRP6 (blocking Wnt ligand-dependent pathway activation) and a third module that binds to human serum albumin to extend its half-life. Zr-BI 905677 was developed as a diagnostic PET imaging tracer to evaluate the biodistribution, tumor uptake, and receptor blockade of BI 905677 in patients with advanced unresectable or metastatic solid tumors harboring RNF43 mutations or R-Spondin (RSPO) fusions. A Phase I open-label PET imaging study (NL-OMON49457) was initiated to evaluate the tracer, but clinical development of the parent therapeutic was terminated due to a narrow therapeutic index and limited efficacy.

Other names

[89Zr]Zr-BI 905677zirconium-89 BI 905677zirconium89 BI 905677zirconium 89 BI 905677[89Zr]Zr-BI-905677