Verinurad (RDEA3170) is a selective uric acid reabsorption inhibitor in clinical development for the treatment of gout and asymptomatic hyperuricemia. Verinurad specifically inhibits URAT1 with a potency of 25 nM. High affinity inhibition of uric acid transport requires URAT1 residues Cys-32, Ser-35, Phe-365 and Ile-481. Unlike other available uricosuric agents, the requirement for Cys-32 is unique to verinurad. Verinurad doses as low as 2.5 mg produce significant sUA lowering in humans, and this greater reduction in sUA may lead to improved outcomes and medical benefits for patients with gout. Verinurad in monotherapy studies has been associated with increased urinary uric acid concentrations and low rates of serum creatinine (sCr) elevation. Verinurad combined with febuxostat decreased sUA dose-dependently while maintaining uric acid excretion similar to baseline. All dose combinations of verinurad and febuxostat were generally well tolerated.

Scyllo-inositol (ELND005) is an inositol isoform. Inositol is a derivative of cyclohexane with six hydroxyl groups, making it a polyol. It also is known as a sugar alcohol, having exactly the same molecular formula as glucose or other hexoses. Scyllo-inositol (ELND005) is a naturally occurring plant sugar alcohol found most abundantly in the coconut palm. It appears to accumulate in a number of human tissues and biofluids through dietary consumption. It has traditionally been considered to be a B vitamin although it has an uncertain status as a vitamin and a deficiency syndrome has not been identified in man. Although scyllo-inositol (ELND005) at pharmacologic doses may alter myo-inositol levels and indirectly affect phosphatidyl-inositol signaling, its main effects are thought to be binding and inhibition of beta-amyloid 42 peptide aggregation and formation of beta-amyloid fibrils. In transgenic animals, scyllo-inositol (ELND005) reduced brain beta-amyloid concentrations and plaque burden, preserved synaptic density, and improved learning deficits. Scyllo-inositol (ELND005) also appears to neutralize toxic effects of beta-amyloid oligomers, including amelioration of oligomer-induced synaptic loss, long-term potentiation inhibition, and memory deficits. Scyllo-inositol (ELND005) is an attractive candidate as a potential disease-modifying oral treatment for Alzheimer disease.

Vatiquinone is the international non-proprietary name for Edison Pharmaceuticals’ EPI-743, an orally bioavailable small molecule being developed by the company for inherited mitochondrial diseases. EPI-743 is a member of the para-benzoquinone class of drugs. The mechanism of action of EPI-743 involves augmenting the synthesis of glutathione, optimizing metabolic control, enhancing the expression of genetic elements critical for cellular management of oxidative stress, and acting at the mitochondria to regulate electron transport. EPI-743 is a compound being developed by BioElectron (previously known as Edison Pharmaceuticals) to treat Friedreich’s ataxia (FA), a rare, autosomal recessive genetic disorder. The regulation of oxidative stress is disturbed in people with FA. EPI-743 targets NADPH quinone oxidoreductase 1 (NQO1), helping to increase the biosynthesis of glutathione, a compound essential for the control of oxidative stress. The drug does not target any FA-specific biochemical pathways directly, but helps to improve the regulation of cellular energy metabolism in general. Vatiquinone has been investigated for the treatment and prevention of retinopathy, rett syndrome, parkinson's disease, noise-induced hearing loss, and methylmalonic aciduria and homocystinuria, Cblc type. The FDA previously granted orphan drug designation for Edison’s EPI-743 to treat inherited respiratory chain diseases of the mitochondria and Friedreich’s ataxia. The company received orphan drug designation for EPI-743 from the Japanese Ministry of Health, Labour and Welfare and European Medicines Agency Committee on Orphan Products for the treatment of Leigh syndrome.

Recilisib (also known as EX-RAD or ON-01210) is a radioprotectant, which means that this compound can protect cells from harmful effects of ionizing radiation. Unlike other radioprotectors, recilisib is not a free-radical scavenger or responsible for cell cycle arrest. Recilisib was suggested to have a different radiation protection mechanism involving DNA repair pathways. This compound has been studied as prophylactic (use prior to radiation exposure) and therapeutic (after exposure to radiation) drug. In studies with healthy volunteers, recilisib was rapidly absorbed and well-tolerated, with only mild adverse events. Phase I clinical trials have been completed.

Verdiperstat (formerly known as AZD 3241) was developed as a selective inhibitor of myeloperoxidase, an enzyme that acts as a key driver of pathological oxidative stress and inflammation in the brain. Verdiperstat was studied in patients with a number of neurodegenerative disorders, including multiple system atrophy and Parkinson's disease. Verdiperstat participated in phase II clinical trials for both diseases. As a result, studies for Parkinson disease were discontinued. In the case of multiple system atrophy, the drug has received the orphan drug status.

Swainsonine is an indolizidine alkaloid found in Australian Swainsona canescens, North American plants of the genera Astragalus and Oxytropis and also in the fungus Rhizoctonia leguminocola. It is competitive inhibitor of Golgi alpha-mannosidase II and lysosomal alpha-mannosidases. This compound has been reported to be a potent antiproliferative and immunomodulatory agent. However, no evidence of anti-tumor activity of swainsonine was seen in phase II clinical trial, in patients with locally advanced or metastatic renal cell carcinoma. Adverse events such as fatigue, nausea and diarrhea were common but generally mild. Swainsonine is locoweed toxin. Locoweed poisoning is seen throughout the world and annually costs the livestock industry millions of dollars. Swainsonine inhibits lysosomal alpha-mannosidase and Golgi mannosidase II. Poisoned animals are lethargic, anorexic, emaciated, and have neurologic signs that range from subtle apprehension to seizures.

Nebracetam (WEB1881FU) is a pyrrolidinone nootropic. Like other racetams, it is an aminomethyl pyrrolidinone derivative of piracetam. It was first synthesized in Germany in the late 1980s, where it was manufactured by Boehringer Ingelheim. Nebracetam is a M1-muscarinic agonist. In Jurkat cells Nebracetam induced a rise of [Ca2+]i in the medium with 1 mM Ca2+ and without Ca2+ (plus 1 mM EGTA). The nebracetam-induced [Ca2+]i rise was blocked by atropine greater than pirenzepine greater than AF-DX 116. Nebracetam facilitates the ganglionic muscarinic transmission through acting on presynaptic sites. Nebracetam has been investigated as a cognition-enhancing drug, but most of the studies have taken place in animal models. It has been shown to protect neurons in animals exposed to low levels of oxygen and low blood sugar. Nebracetam is also protective against glutamate toxicity, presumably via its modulation of calcium entry. In animal models of Alzheimer’s disease, nebracetam improved memory in a dose-dependent manner. It also protected against ischemia- (lack of oxygen) induced neuronal death in a rat model of stroke. The compound has also been tested as a possible antidepressant, presumably because its mechanism of action (reducing dopaminergic and serotonergic uptake) is similar to other commonly used antidepressants. Some studies have taken place in humans. A single dose was shown to alter brain waves in healthy volunteers, who showed increased alpha activity and an associated decrease of slow activity and of fast activity in the frontal cortex. These results imply that nebracetam might improve linguistic learning and memory processing. A trial in dementia patients reported that significant clinical improvement occurred after 8 weeks. However, other studies did not replicate this finding.

Zonampanel (also known as YM872) was developed as selective, potent and highly water-soluble competitive alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist. Zonampanel possesses the neuroprotective effect against focal cerebral ischemia and participated in phase II clinical trials in acute stroke patients. However, because of the severe effects, including hallucinations, agitation, and catatonia the further studied were terminated.

Sipatrigine (BW 619C89), a blocker of neuronal Na+ and Ca2+ channels, has neuroprotective efficacy. This drug was in phase II studies in stroke patients who received iv infusions of sipatrigine. The main adverse events observed were hallucinations and vomiting. The Phase II trial was terminated when Glaxo merged with Wellcome and a decision was made to develop the NMDA (glycine site) receptor antagonist gavestinel (from Glaxo), which showed no efficacy in a randomized, double blind, placebo- controlled trial. It was also assumed, that sipatrigine could have therapeutic potential for major depression and bipolar depression through antagonism of the two-pore-domain K+ channel TREK-1. but further evaluation of its antidepressant therapeutic and toxic effects in animal models is needed before clinical application.

IROXANADINE, a pyridine derivative, is under development for the treatment of atherosclerosis and the complications of atherosclerosis such as ischaemic heart disease, peripheral arterial disease, and restenosis. It induces phosphorylation of p38 stress-activated protein kinase, which plays an important role in endothelial cells (EC) homeostasis. EC function plays a central role in vascular diseases.