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.

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.

Angiotensin (1-7) [Ang 1-7] is a 7 amino acid peptide generated predominantly from Ang II by the action of Ang-converting enzyme 2. Ang 1-7 can act as a negative modulator of aldosterone secretion in vitro and in vivo. The endogenous heptapeptide angiotensin-(1-7) (Ang-(1-7)) is a RAS component that has a central role in the alternative axis. It is generated by the cleavage of Ang-II by the action of the angiotensin converting enzyme 2 (ACE 2) and acts via interaction with the G-protein coupled receptor Mas. Angiotensin (1-7) induces vasorelaxation through release of NO and prostaglandins, perhaps through activation of a non-AT1, non-AT2 receptor, Mas. Counteracts the vasoconstrictive and proliferative effects of angiotensin II and stimulates vasopressin (anti-diuretic hormone) release in vivo. Clinical uses range from treatment of cardiovascular-related diseases, ocular pathologies, metabolic dysfunctions, brain conditions and degenerative diseases to applications in cell differentiation and hematopoiesis, tumor therapy, acute lung injury, fibrosis, infection, among others. Tarix Orphan is developing TXA127 for rare neuromuscular and connective tissue diseases. TXA127 is a pharmaceutical formulation of the naturally occurring peptide, Angiotensin (1-7). TXA127 has been effective in animal models of Duchenne muscular dystrophy (DMD), Limb-girdle muscular dystrophy (LGMD), congenital muscular dystrophy MDC1A, Marfan syndrome, and Dystrophic Epidermolysis Bullosa (DEB). FDA granted rare pediatric disease designation to TXA127 from Tarix to treat recessive dystrophic epidermolysis bullosa (RDEB). TXA127 has been granted orphan drug status by FDA as a treatment for pulmonary arterial hypertension, to enhance engraftment in patients receiving a stem cell transplant, and for Myelodysplastic Syndrome (MDS). Tarix Orphan has broad IP protection for TXA127 and Orphan Drug Designations (ODDs) have been granted for DMD LGMD and DEB in the U.S., and for DMD in Europe. Tarix Orphan aims to initiate a clinical trials for both DMD and DEB in early 2018 and has an active IND for a Phase II trial in DMD, as well as Fast Track designation for DMD.

AC-2592 (glucagon-like peptide 1, or GLP-1) was being in development by Amylin Pharmaceuticals for the treatment of severe congestive heart failure. AC-2592 is a glucagon like peptide 1 receptor agonist.