Peginesatide (trade name Omontys, formerly Hematide), developed by Affymax and Takeda, is an erythropoietic agent, a functional analog of erythropoietin. It was approved by the U.S. Food and Drug Administration for treatment of anemia associated with chronic kidney disease (CKD) in adult patients on dialysis. Peginesatide is a synthetic peptide, attached to polyethylene glycol ("PEGylated"). It mimics the structure of erythropoietin, the human glycoprotein which promotes red blood cell development. Peginesatide binds to and activates the human erythropoietin receptor and stimulates erythropoiesis in human red cell precursors in vitro.

Thymopentin is a synthetic pentapeptide which is the active site of the naturally occurring hormone thymopoietin with immunomodulating properties. Thymopentin can specifically promote the differentiation and maturation of thymic T cells and natural killer cells (NK) and enhance the function of T helper cells. thymic can achieve a two-way adjustment to the immune system by increasing the levels of intracellular cyclic adenosine monophosphate, elevating the activity of T cells, and regulating the proportions of T cell subsets. As an immunomodulating agent, Thymopentin is clinically used in the treatments of autoimmune diseases, such as e.g. atopic dermatitis, chronic lymphocytic leukemia, Sezary's syndrome, rheumatoid arthritis, as well as decreased immune competency in elder surgical patients. Due to poor membrane permeability, extensive metabolism in the GI, and extremely short half-life of 30 s, repeated injections or i.v infusions of Thymopentin are necessary which greatly restrict its clinical applications.

Thymalfasin, a synthetic version of thymosin-α-1, a polypeptide (protein fragment) was being developed by SciClone Pharmaceuticals for the treatment of liver disease. SciClone developed and launched Thymalfasin, under the trade name Zadaxin, for the treatment of hepatitis B and hepatitis C virus infections. The drug is also being developed for the treatment of non-small cell lung cancer (NSCLC), hepatocellular carcinoma, AIDS and malignant melanoma. Thymalfasin exerts a dual action against infections: immune modulating and direct-acting effect. Thymalfasin exerts its immune-modulating activity through the interaction with Toll-like receptors (TLR), a group of proteins involved in the regulation of innate immunity, and in particular with TLR9 and TLR2 on dendritic cells (DCs) and precursor T-cells. Thymalfasin is also able to prevent a pro-inflammatory cytokine storm and possibly autoimmune events. Regarding direct-acting effects, Thymalfasin has been shown to increase the expression of MHC Class I and II, which are important for the antigen presentation and recognition by the immune system of the virally infected cells. v has also been shown to directly inhibit the in vitro growth of virally infected and cancer cells. Thymalfasin is not approved by the FDA but it is widely used in China and some other countries.