Protein-engineered Interleukin-2 XTX202

**Semantic type:** Amino Acid, Peptide, or Protein|Immunologic Factor|Pharmacologic Substance

**Definition:** A modified form of the recombinant form of human endogenous cytokine interleukin-2 (IL-2), that is masked with a protein domain, with potential immunoregulatory and antineoplastic activities. Upon administration of protein-engineered IL-2 XTX202, IL-2 is bound to the protein and pharmacologically inactive. IL-2 does not become active until cleaved by specific proteases in the tumor microenvironment (TME). Upon proteolytic cleavage, unbound and active IL-2 locally binds to the IL-2 receptor beta (CD122) and gamma (CD132) subunits (IL2Rb/g) that are expressed on CD8+ T effector cells and natural killer (NK) cells, thereby activating IL2R-mediated signaling within these immune cells. The activation of T- and NK cells mediate cytolytic immune responses against tumor cells causing tumor cell destruction and inhibition of tumor cell proliferation. XTX202 does not bind to IL-2 receptor alpha (IL-2Ra) and does not cause IL-2Ra-mediated toxicities. The selective activation in the TME enhances the IL-2-mediated cytolytic responses against tumor cells while sparing the unwanted effects of systemic, peripheral immune activation.

**Synonyms:** - Engineered IL-2 Prodrug XTX202 - Modified IL-2 XTX202 - Protein-engineered IL-2 XTX202 - Tumor-selective IL-2 XTX202 - XTX 202 - XTX-202 - XTX202