Discovery of an orally bioavailable, CNS active pan-mutant RET kinase heterobifunctional degrader

  • RSC Med Chem. 2025 Aug 13. doi: 10.1039/d5md00337g.
Douglas L Orsi  1 Kiel E Lazarski  1 Reina Improgo  1 R V Agafonov  1 Jae Young Ahn  1 Joelle Baddour  1 Katelyn Cassidy  1 Prasoon Chaturvedi  1 Kyle S Cole  1 Richard W Deibler  1 W Austin Elam  1 Mark E Fitzgerald  1 Victoria J Garza  1 Andrew Good  1 Christopher H Hulton  1 Marta Isasa  1 Katrina L Jackson  1 Ping Li  1 Yanke Liang  1 Ryan E Michael  1 Morgan Welzel O'Shea  1 Moses Moustakim  1 Samantha Perino  1 Fazlur Rahman  1 Matthew J Schnaderbeck  1 Nicholas P Stone  1 Bonnie Tillotson  1 Gesine K Veits  1 Abigail Vogelaar  1 Jeremy L Yap  1 Robert T Yu  1 Hongwei Huang  1 James A Henderson  1
Affiliations
  • 1. C4 Therapeutics 490 Arsenal Way, Suite 120 Watertown MA 02472 USA [email protected].
Abstract

Point mutations and chromosomal fusions of the Rearranged During Transfection (RET) transmembrane receptor tyrosine kinase cause constitutive substrate-free activation, driving numerous human cancers. RET-selective kinase inhibitors (selpercatinib, pralsetinib) are in current clinical use for RET-driven tumors. However, the emergence of resistance mutations, such as those at the solvent-front G810 residue, results in reduced efficacy. We sought to exploit the event-driven pharmacology of targeted protein degradation to achieve pan-mutant activity against RET-driven cancers with a single selective RET degrader, while utilizing non-phthalimide Cereblon (CRBN) ligands to discover orally bioavailable heterobifunctional degraders. Here we describe the medicinal chemistry efforts that led to compound 20, an orally bioavailable, brain-penetrant, pan-mutant and pan-fusion RET heterobifunctional degrader.

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