Efaroxan (RX 821037) is a potent and selective alpha(2)-adrenoceptor antagonist. Additionally, Efaroxan is a selective antagonist at the imidazoline I1 receptor. Efaroxan promotes insulin secretion, in the absence of exogenous agonists, by a mechanism that involves inhibition of ATP-regulated K+ channels. Efaroxan was in clinical trials for the treatment of diabetes mellitus however its development has been discontinued.

Cirazoline is an agonist of alpha1A adrenergic receptor, a partial agonist of alpha1B and alpha1D receptors, and an antagonist of alpha2 adrenergic receptors. Cirazoline was used to study the biologic function of adrenergic receptors. Injection of cirazoline into to the paravenricular hypothalamic nucleus of rats suppressed food and water intake. Cirazoline caused a large renal vasopressor response in rats. Systemic administration of cirazoline impaired spatial working memory in monkeys.

Tinazoline is an imidazole derivative patented by Ciba-Geigy A.-G. as vasoconstrictors, particularly as nasal decongestants in the treatment of common cold. Tinazoline showing potent and long-acting vasoconstrictor activity on several vascular beds in dogs, guinea-pigs, cats, and rabbits. The vasoconstrictor effect has been shown in animals to be due to a stimulation of the 1-adrenoceptors and the compound does not exhibit any B-adrenoceptor agonist activity.

3-[(4-Methyl-1-piperazinyl)carbonyl]-7-oxabicyclo[2.2.1]heptane-2-carboxylic acid (LB-100) is an experimental cancer therapeutic with cytotoxic activity against cancer cells in culture and antitumor activity in animals. It is an intravenously administered, small-molecule, serine-threonine protein phosphatase (PP2A) inhibitor, being developed by Lixte Biotechnology Holdings. LB-100 delivers an active metabolite into the cell, potently inhibiting specifically the s/t ptases PP2A. Inhibition of PP2A markedly potentiates the effectiveness of standard anti-cancer drugs and X-ray that exert their clinical benefit by damaging DNA thereby inhibiting faithful cell division. Although the growth of normal cells including those of the bone marrow, GI tract, and hair is also impaired by cytotoxic cancer treatment, cancer cells often have acquired genetic damage that permits their unrestrained growth but also reduces their ability to repair DNA damage. Inhibition of PP2A by LB-100 further impairs DNA repair to a greater extent in the cancer cell than in the normal cell providing more selective killing. LB-100 used alone has modest inhibitory activity against many cancers in model systems, but certain human cancers, possessing unique genetic changes in addition to those reducing DNA damage repair, are particularly vulnerable to inhibition of PP2A by LB-100. Among these is myelodysplastic syndrome (MDS), an increasingly common neoplastic disease, especially in persons aged 65 and older, characterized by failure of the bone marrow. In particular, a variant of MDS termed del(5q)MDS is missing ~50% of its PP2A activity rendering this tumor potentially vulnerable to further pharmacologic inhibition of PP2A

CHF6001 is a phosphodiesterase 4 (PDE4) inhibitor optimised for inhaled delivery and tolerability, for the treatment of Asthma and Chronic Obstructive Pulmonary Disease. CHF6001 was 7- and 923-fold more potent than roflumilast and cilomilast, respectively, in inhibiting PDE4 enzymatic activity. CHF6001 inhibited PDE4 isoforms A-D with equal potency, showed an elevated ratio of high-affinity rolipram binding site versus low-affinity rolipram binding site and displayed >20,000-fold selectivity versus PDE4 compared with a panel of phosphodiesterases. CHF6001 effectively inhibited the release of tumor necrosis factor-α from human peripheral blood mononuclear cells, human acute monocytic leukemia cell line macrophages (THP-1), and rodent macrophages (RAW264.7 and NR8383). CHF6001 has the potential to be an effective topical treatment of conditions associated with pulmonary inflammation, including asthma and chronic obstructive pulmonary disease.

CUDC-305, is a novel heat shock protein 90 (HSP90) inhibitor with strong affinity for HSP90 alpha/beta, high oral bioavailability and potent anti-proliferative activity against a broad range of cancer cell lines (with a mean IC50 of 220 nmol/L), including many non-small cell lung cancer (NSCLC) cell lines which are resistant to standard-of-care (SOC) agents. In both laboratory and animal testing, CUDC-305 demonstrated high potency in vitro and/or in vivo across a wide range of cancers. Most notably, Curis scientists observed complete tumor regression following oral administration of CUDC-305 in a mouse xenograft model of acute myelogenous leukemia (AML). Tumor regression has also been observed after treatment of CUDC-305 in mouse xenograft models of breast, non-small cell lung, gastric cancer and glioblastoma brain cancers. In this preclinical testing, the compound also demonstrated an ability to effectively cross the blood brain barrier, and demonstrated an ability to extend survival in an intracranial glioblastoma model. Early stage toxicity studies suggest that CUDC-305 appears to have a better therapeutic window than several leading Hsp90 inhibitors in clinical development.

Quinazosin is a diaminoquinazoline derivative patented by Pfizer, Chas., and Co., Inc. as a hypotensive agent. Quinazosin acts as adrenoreceptor antagonist and in preclinical studies lowered systolic blood pressure in conscious hypertensive dogs, without having any significant effect on their heart rate. Quinazosin lowered blood pressure and reduced total peripheral vascular resistance, while the duration of these effects was dose-dependent. In cats, Quinazosin reduced or reversed the pressor effects of epinephrine, but did not alter those of angiotensin amide.

Fipamezole is a fluorine substituted imidazole compound with high antagonist specificity for the presynaptic alpha2-adrenoceptor. There were no significant differences between the affinity of Fipamezole for the different subtypes, thus characterizing Fipamezole as a non-subtype–selective alpha2 antagonist. Fipamezole had been in phase III clinical trials for the treatment of dyskinesia associated with Parkinson’s disease. Detected side effects are hypertension, nausea, vomiting, dysgeusia, facial flushing.

Avelestat, also known as AZD9668, is a novel, oral inhibitor of neutrophil elastase (NE), an enzyme implicated in the signs, symptoms, and disease progression in NE-driven respiratory diseases such as bronchiectasis, Cystic Fibrosis and chronic obstructive pulmonary disease via its role in the inflammatory process, mucus overproduction, and lung tissue damage. Its development was discontinued due to unknown reasons. Nevertheless, this drug in the phase II of clinical trial as adjunctive therapy in improving insulin sensitivity of insulin-resistant type 2 diabetic subjects. The drug's clinical profile suggests that it will be well tolerated with few, if any, side effects, and the existence of simple methods that can indirectly measure its activity in vivo.