Corticotropin is a polypeptide hormone produced and secreted by the pituitary gland. Corticotropin acts through the stimulation of cell surface the adrenocorticotropic hormone (ACTH) receptors, which are primarily located on the adrenocortical cells. Corticotropin stimulates the cortex of the adrenal gland and boosts the synthesis of corticosteroids, mainly glucocorticoids but also sex steroids (androgens). Corticotropin is indicated as monotherapy for the treatment of exacerbations of multiple sclerosis in adults and infantile spasms in infants and children under 2 years of age. Controlled clinical trials have shown Corticotropin to be effective in speeding the resolution of acute exacerbations of multiple sclerosis. However, there is no evidence that it affects the ultimate outcome or natural history of the disease. The mechanism of action of Corticotropin in the treatment of infantile spasms is unknown.

Argipressin is a neurohypophysial hormone from the vasopressin hormone family. Its two primary functions are to retain water in the body and to constrict blood vessels. The antidiuretic action of Argipressin is ascribed to increase in reabsorption of water by the renal tubules. Argipressin can cause contraction of smooth muscle of the gastrointestinal tract, gall bladder, urinary bladder and all parts of the vascular bed, especially the capillaries, small arterioles and venules with less effect on the smooth musculature of the large veins. Agripressin for injections is used for use in diabetes insipidus, when this is not of nephrogenic origin and control of bleeding from oesophageal varices. In addition, argipressin is indicated to increase blood pressure in adults with vasodilatory shock (e.g., post-cardiotomy or sepsis) who remain hypotensive despite fluids and catecholamines.

More than a century ago, Sir Henry Dale demonstrated that a component of the pituitary causes contractions of the mammalian uterus, hence his coining the term “oxytocic,” derived from the Greek for “quick birth,” for its activity. The discovery that a component of the pituitary causes milk secretion followed within a few years. By 1930, oxytocin was separated from vasopressin into pitocin and pitressin, respectively, at Parke Davis and made available for research. That a single peptide was responsible for these uterine and mammary actions was definitively confirmed upon the sequencing and synthesis of the peptide, 9 amino acids in length. Vincent du Vigneaud was awarded a Nobel Prize for this work. Oxytocin is indicated for the initiation or improvement of uterine contractions, where this is desirable and considered suitable for reasons of fetal or maternal concern, in order to achieve vaginal delivery. Oxytocin is indicated to produce uterine contractions during the third stage of labor and to control postpartum bleeding or hemorrhage. Uterine motility depends on the formation of the contractile protein actomyosin under the influence of the Ca2+- dependent phosphorylating enzyme myosin light-chain kinase. Oxytocin promotes contractions by increasing the intracellular Ca2+. Oxytocin has specific receptors in the myometrium and the receptor concentration increases greatly during pregnancy, reaching a maximum in early labor at term. The Oxytocin receptor is a typical class I G protein-coupled receptor that is primarily coupled via G(q) proteins to phospholipase C-beta. The high-affinity receptor state requires both Mg(2+) and cholesterol, which probably function as allosteric modulators. The agonist-binding region of the receptor has been characterized by mutagenesis and molecular modeling and is different from the antagonist binding site. The function and physiological regulation of the Oxytocin system is strongly steroid dependent.

Nelipepimut-S (formerly known as E75) is an immunogenic peptide from the HER2 protein that is highly expressed in breast cancer. The NeuVax™ (Galena, OR, USA) vaccine, nelipepimut-S plus granulocyte-macrophage colony-stimulating factor, is designed for the prevention of clinical recurrences in high risk, disease-free breast cancer patients. Nelipepimut-S is being developed by Sellas Life Sciences Group. When combined with the immunoadjuvant granulocyte-macrophage colony-stimulating factor (GM-CSF), nelipepimut-S has been used as a vaccine that is capable of eliciting a robust anti-HER2 immune response. Early-phase clinical trials that enrolled women with node-positive or high-risk node-negative breast cancer who had been rendered disease free with standard of care therapy but were at risk for recurrence, demonstrated the vaccine to be safe with a suggestion of clinical benefit. Nelipepimut-S is currently being evaluated in a Phase III clinical trial.

Aviptadil, a vasoactive intestinal polypeptide, is a vasodilator and lowers blood pressure if administered intravenously. In 2007, the orphan designation was granted by the European Commission for aviptadil for the treatment of sarcoidosis, a disease of unknown cause that affects many organs and tissues, most commonly the lungs. Sarcoidosis is characterized by specific microscopic lesions called granulomas. Aviptadil is able to influence the immune system that decreases the inflammatory processes seen in sarcoidosis by acting on the white blood cells (lymphocytes and monocytes) involved in the formation of the granulomas. In combination with phentolamine, the drug is used to treat erectile dysfunction. In addition, aviptadil has been studied in phase II clinical trials for patients with respiratory distress syndrome.

TAT-NR2B9C is a synthetic peptide fusion of the nine C-terminal residues of the NR2B subunit of the N-methyl-D-aspartate (NMDA) receptor and the cell membrane protein transduction domain of the HIV-1 tat protein. It is a postsynaptic density protein-95 (PSD95) inhibitor with neuroprotective properties. It is under development for the treatment of acute stroke and acute cerebral ischemia.