Thymosin Alpha 1

A synthetic N-acetylated 28-amino-acid peptide (CAS 62304-98-7) corresponding to the N-terminal fragment of the 109-residue precursor prothymosin-alpha produced by thymic epithelial cells. Binds Toll-like receptors 2 and 9 on dendritic and plasmacytoid dendritic cells, triggering MyD88/TRIF signaling that upregulates IL-12, IFN-alpha, and Th1 T-cell activation. Marketed by SciClone Pharmaceuticals as Zadaxin in ~35 countries for chronic hepatitis B, hepatitis C, certain cancers (HCC, NSCLC, melanoma), and as a vaccine adjuvant. Holds FDA Orphan Drug designation in the US; not FDA-approved.