FERTIRELIN is an analog of luteinizing hormone releasing factor. The drug has been used since 1981 in Japan to treat various types of reproductive failure in cattle.

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.

Enfuvirtide is a linear 36-amino acid synthetic peptide that inhibits the fusion of HIV-1 with CD4 cells. Enfuvirtide works by disrupting the HIV-1 molecular machinery at the final stage of fusion with the target cell, preventing uninfected cells from becoming infected. Enfuvirtide interferes with the entry of HIV-1 into cells by inhibiting fusion of viral and cellular membranes. Enfuvirtide binds to the first heptad-repeat (HR1) in the gp41 subunit of the viral envelope glycoprotein and prevents the conformational changes required for the fusion of viral and cellular membranes. Enfuvirtide is indicated for the treatment of HIV-1 infection, in combination therapy with other antiretrovirals, in patients where all other treatments have failed. Common adverse drug reactions associated with enfuvirtide therapy include: injection site reactions (pain, hardening of skin, erythema, nodules, cysts, itch; experienced by nearly all patients, particularly in the first week), peripheral neuropathy, insomnia, depression, cough, dyspnoea, anorexia, arthralgia, infections (including bacterial pneumonia) and/or eosinophilia.

Desirudin (Iprivask), a recombinant hirudin, is a parenteral direct thrombin inhibitor approved to prevent venous thromboembolism in patients undergoing elective hip replacement surgery. Desirudin is a potent inhibitor of both clot-bound and freely circulating thrombin. Desirudin acts independently of anti-thrombin, forming a noncovalent irreversible complex with both the active site of thrombin as well as the fibrinogen binding site. This Desirudin–thrombin complex prevents fibrinogen cleavage and other thrombin catalyzed reactions such as the activation of clotting factors V, VIII and XIII, and thrombininduced platelet activation, resulting in a dose-dependent prolongation of activated partial thromboplastin time (aPTT). Desirudin is highly selective and has no effect on plasmin, factors IXa and Xa, tissue plasminogen activator, activated protein C, trypsin, chymotrypsin or complement activation pathways. Bleeding complications reported with the use of desirudin in patients undergoing hip-replacement surgery are similar to those reported with heparin and enoxaparin.

Nesiritide is the recombinant form of the 32 amino acid human B-type natriuretic peptide (BNP), which is normally produced by the ventricular myocardium. Human BNP binds to the particulate guanylate cyclase receptor of vascular smooth muscle and endothelial cells, leading to increased intracellular concentrations of guanosine 3'5'-cyclic monophosphate (cGMP) and smooth muscle cell relaxation. Cyclic GMP serves as a second messenger to dilate veins and arteries. Nesiritid was sold under brand name Natrecor for the intravenous treatment of patients with acutely decompensated congestive heart failure who have dyspnea at rest or with minimal activity.