F-899, under development, is intended to treat patients with growth deficiency and wasting diseases. F-899 is a recombinant fusion protein containing human growth hormone (GH) and human IgG2-Fc and is expressed in Chinese Hamster Ovary (CHO) cells. F-899 has an immunoglobulin-like structure. It consists of two GH molecules at the N-terminal of Fc fragments (a GH dimer). F-899 shows longer serum half-life compared to the long-acting growth hormone (PEGylated growth hormone). The PEGylated GH requires weekly dosing. F-899 may benefit patients with reduced frequency of dosing, either bi-weekly or monthly.