Paquinimod is an immunomodulatory compound preventing S100A9 binding to TLR-4. It was studied in experimental osteoarthritis, in patients with mild active systemic lupus erythematosus and in systemic sclerosis patients. In January 2014, the US FDA granted orphan drug designation to paquinimod for the treatment of systemic scleroderma. The Orphan designation is implemented to promote the development of drugs that may provide significant benefit to patients suffering from rare diseases identified as life threatening or chronically debilitating. The further development of paquinimod for systemic lupus erythematosus and rheumatoid arthritis was discontinued.

Amenamevir is an antiviral agent discovered by Astellas Pharma Inc. and is considered to exert anantiviral effect by inhibiting the activity of the helicase-primase complex, which is involved in DNA replication of herpes virus. It is a helicase-primase inhibitor against herpes simplex virus 1 (HSV-1), HSV-2, and varicella zoster virus. Amenamevir inhibited the in vitro replication of HSV-1 with a mean 50% effective concentration (EC(50)) of 14 ng/ml. Amenamevir was approved in Japan for the treatment of Herpes zoster.

Amelubant, its metabolite BIIL 260 (formed by removal of the ethoxycarbonyl protecting group), and its major metabolite BIIL 315 (formed by removal of the protecting group and glucuronidation) had potent in vitro and in vivo Leukotriene B4 receptor antagonistic properties. Amelubant has been in phase II clinical trials by Boehringer Ingelheim for the treatment of cystic fibrosis, chronic obstructive pulmonay disease, bronchial asthma and rheumatoid arthritis. However, this research has been discontinued. In 2002, orphan drug designation was received in E.U. for the treatment of cystic fibrosis. Serious adverse events of Amelubant were characterized by increased presentation of respiratory signs and/or symptoms associated with pulmonary exacerbation and resulted in admission to a hospital and/or administration of IV antibiotics.

Dexnafenodone is a dual of adrenergic receptor antagonist and serotonin uptake inhibitor potentially for the treatment of major depressive disorder. Drug induced a rapid and marked suppression of REM sleep, and in parallel an increase in chin muscle tone during NREM sleep. Dexnafenodone produced a frequency- and voltage-dependent inhibition of the fast sodium channels similar to that exhibited with imipramine. It inhibited voltage- and agonist-stimulated Ca2+ entry in isolated rat aortas. In addition, it decreased Ca2+ content in both resting and noradrenaline-stimulated muscles, suggesting that it may deplete noradrenaline-sensitive intracellular Ca2+ stores. As a consequence, dexnafenodone would reduce the concentration of intracellular free Ca2+ available at the contractile apparatus for vascular smooth muscle contraction. Dexnafenodone exerted fewer cardiodepressant effects than imipramine and desipramine in isolated guinea-pig atrial and ventricular muscle fibres less.

Anidoxime is unrelated to other analgesic agents in clinical use. It is the hydrochloride salt of 0-(4-methoxyphenyl-carboxyl)-3-diethylamino-propiophenone oxime, with an empirical formula C21H27N3O3 HCl. It was in clinical trial as an oral analgesic agent.

Burapitant (SSR-240,600) is a drug developed by Sanofi-Aventis which was one of the first compounds developed that acts as a potent and selective antagonist for the NK1 receptor. Burapitant inhibited the binding of radioactive substance P to tachykinin NK1 receptors in human lymphoblastic IM9 cells, human astrocytoma U373MG cells, and human brain cortex. It also showed a subnanomolar affinity for guinea pig NK1 receptors but was less potent on rat and gerbil NK1 receptors. Burapitant inhibited [Sar(9),Met(O2)(11)]substance P-induced inositol monophosphate formation in human astrocytoma U373MG cells. Burapitant (0.1-10 mg/kg i.p. or p.o.) antagonized the excitatory effect of i.c.v. infusion of [Sar(9),Met(O2)(11)]substance P (SP) on the release of acetylcholine in the striatum of anesthetized and awake guinea pigs. This antagonistic action was still observed after repeated administration of Burapitant (5 days, 10 mg/kg p.o., once a day). Burapitant (10 mg/kg i.p.) inhibited the phosphorylation of the cAMP response element-binding protein in various brain regions induced by i.c.v. administration of [Sar9,Met(O2)(11)]SP. While burapitant itself did not proceed beyond early clinical trials and was never developed for clinical use in humans, promising animal results from this and related compounds have led to a number of novel drugs from this class that has now been introduced into medical use.

Hydroxypioglitazone (M-IV) is an active metabolite of the peroxisome proliferator-activated receptor γ (PPARγ) agonist pioglitazone. Experiments in vitro have shown that hydroxypioglitazone was more efficient than the parent drug in stimulating lipid synthesis.

Atilmotin (also known as BAX-ACC-1638), a motilin receptor agonist, is short acting, with t1/2 less than 10 min. It was shown that at doses of 6, 30 or 60 mg intravenously, it affected esophageal, lower esophageal sphincter (LES), and gastric motility. LES and gastric pressures were increased, whereas there was disruption of esophageal peristalsis characterized by lower amplitude and failed contractions. The drug can have the clinical implementation for stomach motility disorders but is needed further study.