XA-1

**XA-1** is a designation that refers to multiple distinct preclinical therapeutic candidates in the biomedical literature. Most prominently, it represents a de novo designed single-domain (VHH) antibody (nanobody) developed by **Xaira Therapeutics** for oncology indications. Generated in seven weeks using Xaira's generative AI platform, **X-Design** (specifically the Vega model), XA-1 was optimized simultaneously for high-affinity binding to a precision-constrained epitope, developability, and cross-reactivity with surrogate species (showing a $K_D$ of 17 nM for the human target and 83 nM for the cynomolgus homolog). Separately, **XA-1** refers to an academic preclinical mRNA-encoded bispecific antibody designed to co-block the **programmed cell death protein 1 (PD-1)** and **programmed death-ligand 1 (PD-L1)** pathways. Delivered via lipid nanoparticles (LNPs), this bispecific construct features ablated Fc effector functions and is designed to promote T-cell mediated anti-tumor activity, particularly in colorectal cancer models. Additionally, **XA-1** has been used to designate a peptide-based GLP-1 receptor agonist analog of AWRK6 developed for type 2 diabetes.