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.

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.

Zolertine is an alpha-adrenergic receptor antagonist that acts as an antihypertensive agent. Its effect was studied in animals in vivo and in vitro. Zolertine considerably decreased systemic blood pressure in mecamylamine hypertensive dogs in a dose-related fashion. Using the intravital microscopic method in rat's mesocygeus microvasculature a direct relationship between zolertine dosage and blockade was demonstrated as well as an inverse relationship between time of action of zolertine and percentage of vasoconstriction caused by noradrenaline. When only zolertine was applied, it caused a small vasoconstriction that decreased as its concentration increased which could be due to its ability to antagonize alpha receptor responses, but not beta responses. Zolertine is a more active alpha blocker than azapetin, a blocker used in medical practice. Competition binding experiments using the alpha1-adrenoceptor antagonist [3H] prazosin showed a zolertine pKi of 6.81 +/- 0.02 in rat liver (alpha1B-adrenoceptors) and 6.35 +/- 0.04 in rabbit liver (alpha1A-adrenoceptors) membranes. Zolertine showed higher affinity for alpha1D-adrenoceptors compared to alpha1A-adrenoceptors, while it had an intermediate affinity for alpha1B-adrenoceptors. The ability of the alpha1-adrenoceptor antagonist zolertine to block alpha1D-adrenoceptor-mediated constriction in different vessels of Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats may explain its antihypertensive efficacy despite its low order of potency.

Rezatomidine (AGN 203818) is an alpha adrenergic receptor agonist that was developed for the treatment of chronic pain conditions. Phase II studies have evaluated the safety and effectiveness of rezatomidine in treating the pain in patients with fibromyalgia, irritable bowel syndrome, interstitial cystitis, and diabetic neuropathy. However, three studies were terminated early based on a business decision. Pancreatitis, gastric ulcer, viral infections and dehydration were reported as serious adverse events in patients when administered a 60mg dose.