Revospirone (BAY VQ 7813) is a pyrimidinylpiperazine derivative that acts as partial agonist at 5-HT1A receptors. Head shakes were reported after administration of revospirone in pigs, and once daily administration for 3-5 days led to a reduction in this head shake response. No behavioral alterations were observed. This compound was never marketed

CP-601927 is a selective α4β2 nicotinic acetylcholine receptor partial agonist developed by Pfizer. The compound has antidepressant-like activity in animal models and was investigated in a phase 2 trial as an augmentation to other antidepressant therapy in patients with Major Depressive Disorder. However, CP-601927 ultimately lacked efficacy as an adjuvant in these patients because of insufficient activity of α4β2 at therapeutic doses.

INT-131, a novel, non-thiazolidinedione (TZD), selective peroxisome proliferator-activated receptor (PPAR) gamma modulator and partial agonist, which was investigated in phase II of clinical trial for the treatment of type 2 diabetes mellitus (non-insulin dependent diabetes) and Multiple Sclerosis, Relapsing Remitting. The concept of selective modulation involves targeting and activating specific genes to minimize side effects while maintaining therapeutic benefits. In vitro, INT-131 attenuated adipogenic properties, indicating moderate PPAR gamma activation/cofactor recruitment compared with the full agonistic properties of TZD compounds.

NGX267 is a partial muscarinic receptor agonist with functionally specific M1 and M3 receptor activity, developed by Torrey Pines Therapeutics(TPTX) for the treatment of Xerostomia, Alzheimer’s disease and cognitive deficits in schizophrenia. NGX-267 had been in phase II clinical trials for the treatment of Xerostomia, however, all researchers on this drug candidate were discontinued.

Rapastinel (formerly known as GLYX-13) is an investigational intravenous formulation of a novel NMDA receptor partial agonist, which is being evaluated for adjunctive treatment of Major depressive disorder, and has shown a rapid onset of antidepressant efficacy 1 day after a single dose in a Phase 2 clinical trial of patients with Major depressive disorder who had an inadequate response to one or more antidepressants. No psychotomimetic or hallucinogenic side effects were observed with rapastinel. Few adverse events were reported by 5% or more of subjects and these were rated as mild or moderate. These included headache, somnolence, dizziness, dysgeusia, and fatigue. On January 29, 2016, Allergan (who acquired Naurex in July 2015) announced that rapastinel had received Breakthrough Therapy designation from the U.S. FDA for adjunctive treatment of major depressive disorder.

Encenicline (EVP-6124; MT-4666) acts as a potent partial and selective agonist at alpha-7 nicotinic acetylcholine receptor. Encenicline significantly improved memory function in animal models. FORUM Pharmaceuticals (formerly EnVivo Pharmaceuticals) is developing encenicline for the treatment of cognition disorders such as schizophrenia and for Alzheimer's disease.

Vaccenic acid (VA) (t11 octadecenoic acid) is a positional and geometric isomer of oleic acid (c9-octadecenoic acid), and is the predominant trans monoene in ruminant fats (50%–80% of total trans content). Dietary VA can be desaturated to cis-9,trans-11 conjugated linoleic acid (c9,t11-CLA) in ruminants, rodents, and humans. Hydrogenated plant oils are another source of VA in the diet, and it has been recently estimated that this source may contribute to about 13%–17% of total VA intake. In contrast to suggestions from the epidemiological studies, the majority of studies using cancer cell lines (Awad et al. 1995; Miller et al. 2003) or rodent tumors (Banni et al. 2001; Corl et al. 2003; Ip et al. 1999; Sauer et al. 2004) have demonstrated that VA reduces cell growth and (or) tumor metabolism. Animal and in vitro studies suggest that the anti-cancer properties of VA are due, in part, to the in vivo conversion of VA to c9,t11-CLA. However, several additional mechanisms for the anti-cancer effects of VA have been proposed, including changes in phosphatidylinositol hydrolysis, reduced proliferation, increased apoptosis, and inhibition of fatty acid uptake. In conclusion, although the epidemiological evidence of VA intake and cancer risk suggests a positive relationship, this is not supported by the few animal studies that have been performed. The majority of the studies suggest that any health benefit of VA may be conferred by in vivo mammalian conversion of VA to c9,t11-CLA. VA acts as a partial agonist to both peroxisome proliferator-activated receptors (PPAR)-α and PPAR-γ in vitro, with similar affinity compared to commonly known PPAR agonists. Hypolipidemic and antihypertrophic bioactivity of VA is potentially mediated via PPAR-/-dependent pathways.

FLESINOXAN, a phenylpiperazine derivative, is a selective agonist for 5-HT1A receptors. It is an antidepressant agent which clinical development was stopped.

Capadenoson (BAY 68-4986) is a nonnucleoside agonist for the A1 Adenosine Receptor (A1AR) and the A2BAR. Capadenoson has undergone two Phase IIa clinical trials, initially in patients with atrial fibrillation and subsequently in patients with stable angina. Capadenoson has also been shown to decrease cardiac remodeling in an animal model of advanced heart failure and a capadenoson derivative, neladenoson bialanate, recently entered clinical development for the treatment of chronic heart failure. The therapeutic effects of capadenoson are currently thought to be mediated through the A1AR.

MK-0773 is an orally active selective androgen receptor modulator. The safety and efficacy of MK-0773 was evaluated in sarcopenic elderly women. The MK-0773- induced improvements in lean body mass were not accompanied by statistically significant improvements in physical function. Higher dose of MK-0773 or longer duration of therapy might have resulted in improvements in physical function, but liver transaminase elevations likely preclude further development of MK-0773. Drug-candidate had been in phase I clinical trials for the treatment of osteoporosis.