PF-03654746 is a potent, selective antagonist of the human H3 receptor, developed by Pfizer. It was in the clinical trial phase II for the treatment of excessive daytime sleepiness (EDS) associated with narcolepsy, Tourette syndrome as well as potential anti-allergy applications and in phase I of clinical trial for the treatment of Schizophrenia and Alzheimer's disease, but these investigations were discontinued.

Ibutamoren (L-163,191 MK-0677) is a spiropiperidine agonist of the ghrelin receptor and a growth hormone secretagogue. Ibutamoren mimics the actions of growth hormone releasing peptide-6 to increase serum levels of serum insulin-like growth factor-I (IGF-I). Orally active Ibutamoren was being developed by Merck & Co. for a variety of indications, including fibromyalgia, muscle wasting/weakness in patients with chronic kidney disease, Alzheimer's disease and fractures.However, there has been no recent development reported or development has been discontinued for these indications.

Saracatinib (AZD0530) is an oral, dual inhibitor of c-Src/Abl kinases initially developed by AstraZeneca for the treatment of cancer. The drug was tested for many neoplasms and reached phase III for ovarian cancer (in combination with paclitaxel), however without demonstrating any significant effect. Sarcatinib is also tested in patients with Alzheimer's Disease (Phase II). Its effect on Alzheimer's Disease patients is explained by inhibition of another kinase, Fyn, which is highly expressed in brain.

Tesofensine (also known as NS-2330) is a novel triple monoamine reuptake inhibitor with intrinsic inhibitory activity on norepinephrine (NE), serotonin (5-HT), and dopamine (DA) transporter function. It was development by NeuroSearch as a potential therapy for Alzheimer's disease (AD) and Parkinson's diseases, but these efforts have been discontinued. In phase II clinical trials with tesofensine in obese individuals, dose-related reductions in body weight, body fat and waist circumference, as well as improvements in other obesity-related endocrine factors were observed and the FDA recently endorsed the phase III trial program for this agent.

Xanomeline (LY-246,708) is an orthosteric muscarinic acetylcholine receptor (mAChR) agonist, often referred to as M1/M4-preferring. It is also known to act as a M5 receptor antagonist. Xanomeline was studied in clinical trials phase I in schizophrenia. In Phase II clinical trials in Alzheimer’s patients, xanomeline significantly improved several measures of cognitive function, yet produced unwanted side effects that limited patient compliance. The side effects seem to be associated with rapid metabolism of the alkyloxy side chain following oral administration, resulting in a nonselective, yet active compound with limited therapeutic utility. Despite a second Phase II clinical trial with a patch formulation, the liabilities of xanomeline still outweigh its benefits.

Talsaclidine (WAL-2014) is a selective full agonist of M1 muscarinic receptor, having partial agonist activity on the M2 and M3 subtypes (with no in vivo consequences). The general receptor profile of talsaclidine demonstrates a nearly specific interaction with muscarinic receptors, having only weak binding affinity for alpha1- and nicotinic receptors. The drug is being tested in phase III of clinical trials for the treatment of Alzheimer's disease.

Alvameline is a partial agonist of the M1 mAChR that also displays M2/M3 antagonist effects. It readily crosses the blood-brain barrier. It has an effect profile that makes it of interest to test its ability to counteract bladder overactivity in humans. Behaviorally, alvameline has been shown to significantly improve Morris water maze (MWM) performance in both young and ageimpaired rats. It failed to improve cognition in patients with mild to moderate Alzheimer's disease.

Etazolate (EHT-0202) is a selective, positive GABAA receptor modulator has completed phase II clinical trials in patients with Alzheimer's disease. It is also a selective phosphodiesterase-4 inhibitor that is specific for cAMP. Etazolate showed anxiolytic and antidepressant activity and could be useful in managing post-traumatic stress disorder.

Tubastatin A is a potent and selective HDAC6 inhibitor with IC50 of 15 nM in a cell-free assay. Tubastatin A is a very selective HDAC6 inhibitor with 100 to over 1000-fold selectivity for HDAC6 over other HDAC classes. Tubastatin A increases the total numbers of mitochondria and restores the number of moving mitochondria in DRG neurons. It reverses the axonal loss in peripheral neurons in the mouse model of Charcot-Marie-Tooth disease. Tubastatin A inhibits the deacetylation of α-tubulin in murine myoblasts.

Coptisine (COP), a protoberberine alkaloid, is widely found in Chinese medicinal plants (family Berberidaceae, Ranunculaceae and Papaveraceae). It is reported that COP has a wide range of pharmacological and biological activities, including antibacterial, hypoglycemic, anti-tumorigenic, and gastric-mucous membrane protection. Considerable attention has been focused on its activity against central nervous system disorders, such as improving the symptoms of Alzheimer’s disease and even preventing its onset, by exerting antidepressant effects as a potent type A monoamine oxidase inhibitor. Coptisine was found to be an efficient uncompetitive Indoleamine 2,3-dioxygenase inhibitor. Coptisine is a potent inhibitor of human organic cation transporters.