Discovery and Characterization of Novel IKZF1/3 Glue Degraders against Multiple Hematological Cancer Cell Lines.

Objectives: Immunomodulatory drugs (IMiDs), functioning as molecular glue degraders, have been approved for treating various hematological malignancies; however, the inevitable acquired drug resistance resulting from their skeletal similarity and hematological toxicities poses significant obstacles to their clinical treatment. The study aimed to develop degraders with potent efficiency and low toxicity.

Methods: Phenotypic profiling, elaborate structure-activity relationships (SAR), rational drug design and degradation profiles investigations, quantitative proteomics analysis and cell-based functional studies, and pharmacokinetic studies were conducted to develop more potent degraders.

Results: This study developed novel CRBN-binding moieties through methylene deletion in lenalidomide's isoindole core. Lead compounds MGD-A7 and MGD-C9 demonstrated superior antiproliferative efficacy vs. IMiDs, with submicromolar potency. MGD-A7 and MGD-C9 significantly and selectively induced the degradation of Ikaros Family Zinc Finger Proteins 1 and 3 (IKZF1/3) with nanomolar potency via a CRBN-dependent pathway. Mechanistically, MGD-A7 and MGD-C9 dramatically induced cell apoptosis and G1 cell cycle arrest and MGD-C9 exhibited favorable pharmacokinetic properties in vivo. Furthermore, MGD-C9 exhibited significant synergistic effects with standard-of-care agents in various hematological malignancy cells.

Conclusions: These results indicate that MGD-C9 could act as a highly effective CRBN ligand and is expected to become a candidate drug for the treatment of hematological malignancies.