Tagraxofusp is a recombinant N-terminal methionylated fusion protein, whose amino acid residues at positions 2 – 389, 390 – 391, and 392 – 524 correspond to amino acid residues at positions 33 – 420 of diphtheria toxin, a linker, and human interleukin-3, respectively. Tagraxofusp is produced in Escherichia coli. Tagraxofusp is a protein consisting of 524 amino acid residues.