IKZF2 (Helios)

Class

IKZF2 (Helios) molecular glue degrader

Pathway

Cereblon (CRBN)-recruiting molecular glue that selectively degrades IKZF2/Helios, destabilizing regulatory T-cell function and reactivating exhausted effector T cells to enhance anti-tumor immunity

IKZF2, also called Helios, is a zinc-finger transcription factor that acts inside regulatory T cells (Tregs), a subset of immune cells whose normal job is to restrain immune responses and prevent autoimmunity. Within tumors, Tregs are often co-opted to suppress the very effector T cells that would otherwise attack cancer cells, and Helios helps stabilize this suppressive Treg identity. Degrading Helios is intended to destabilize Treg-mediated suppression within the tumor microenvironment, allowing exhausted effector T cells to regain anti-tumor activity, without eliminating Tregs systemically or triggering widespread autoimmunity. The compound described here works as a molecular glue degrader: it binds cereblon (CRBN), a component of a cellular protein-disposal machine called an E3 ubiquitin ligase, and reshapes its surface so that it newly recognizes and tags Helios for destruction. This approach is selective for IKZF2 over its close relatives IKZF1 and IKZF3, which are targeted by older CRBN-based immunomodulatory drugs used in blood cancers. That selectivity is the point: it aims to modulate Treg function specifically, rather than producing the broader immune and blood-cell effects associated with degrading the other family members. This mechanism is being explored primarily in solid tumor immuno-oncology, where reversing Treg-mediated suppression could complement other immune-activating therapies.