SYZJ001

**SYZJ001** is an engineered bispecific antibody (bsAb) in the novel IgG–VHH format, combining a human IgG antibody (R15-F7) and a humanized nanobody (P14-F8-35) that bind to non-overlapping epitopes on the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, sterically blocking ACE2 receptor binding and potently neutralizing wild-type virus and alpha, beta, gamma, and delta variants. It demonstrates superior neutralization potency (IC50 as low as 0.003 µg/mL against pseudovirus) and affinity (KD 1.48E-10 M) compared to its parental antibodies, with cooperative blocking effects and improved pharmacokinetics. SYZJ001 showed robust prophylactic and therapeutic efficacy in three SARS-CoV-2 mouse models (MASCp6, beta variant, MASCp36), dramatically reducing viral loads (up to 10^5-fold), preventing lung pathology, and improving survival, positioning it as a promising antiviral candidate.[1][3][6][9]