Atocalcitol is a vitamin D analogue. A hallmark of vitamin D3 analogues in psoriasis amelioration is the ability to inhibit the proliferation of keratinocytes. Atocalcitol had been in phase II clinical trials for the treatment of psoriasis. However, this research has been discontinued.

BMS-582949 acts as a dual action kinase inhibitor. It inhibits both p38 mitogen-activated protein kinase (p38 MAPK) activity and activation of p38. As a blocking agent for activation of p38 kinase BMS-582949 appeared to be well suited to resist such cellular responses that would drive p38 activation more strongly. BMS-582949 is in Phase II clinical trials for the treatment of rheumatoid arthritis, psoriasis, and atherosclerosis.

Atizoram (CP-80633) is a phosphodiesterase IV inhibitor with bronchodilatory and antiinflammatory properties. It was in phase II trials with Pfizer in the US for the treatment of asthma, atopic dermatitis and psoriasis. Development of atizoram has been discontinued in the asthma indication and no recent development has been reported for the other indications. CP-80633 inhibits PDE4 isozymes (human lung IC50 = 1.27 uM) in the absence of effects on PDE1, PDE2, PDE3 and PDE5 isozymes (IC50 > 100 uM). It exhibits no significant selectivity for any single cloned PDE4A, B, C or D isoform.

Cycloheximide is an antibiotic produced by fermentation culture of Streptomyces griseus, Streptomyces noursei, Streptomyces albulus, Streptomyces naraensis, or other cycloheximide-producing microorganism. It was first discovered by A. Whiffen et al. in 1946. She observed the activity of the compound against the yeasts and it became known as the first antifungal antibiotic. Cycloheximide has been marketed as a plant fungicide for many years and this use continues mainly against fungal diseases of turf and for powdery mildew on roses. More recently, cycloheximide has been recognized and is being developed as an abscission agent for citrus fruits and olives. Due to significant toxic side effects, including DNA damage, teratogenesis, and other reproductive effects, cycloheximide is generally used only in in vitro research applications, and is not suitable for human use as a therapeutic compound. Cycloheximide is an antimitotic and an inhibitor of the synthesis of both DNA and protein.

Descinolone acetonide (an analog of triamcinolone acetonide) is a glucocorticoid which was developed for the treatment of skin disorders. It was tested on patients with psoriasis and atopic dermatitis, however there is no information about its further development.

GSK 0660 is a selective PPARdelta antagonist. The compound reduced psoriasis-like changes in a preclinical model and demonstrated neuroprotection in an in vitro model of Parkinson’s disease. When given alone GSK 0660 exhibits inverse agonist effects.

K-252a, a metabolite isolated from the culture broth of Nocardiopsis sp. K-252a, was found to exhibit an extremely potent inhibitory activity on protein kinase C. The IC50 value was 32.9 nM. K252a is a potent inhibitor of various protein kinases including Protein kinase A, Protein kinase C and Protein kinase G. It acts by competition with the ATP binding site with Ki values of 18-25 nM. K252a also acts as a specific and potent inhibitor (IC50 = 3 nM) of Trk receptors and thus selectively blocks the effects of nerve growth factor (NGF) on PC12 cells. At lower concentrations, K252a can act as a neuroprotective compound, promoting survival of primary neuronal cultures. This alkaloid induces apoptosis and cell cycle arrest by inhibiting Cdc2 and Cdc25.4 Recently, K252a was found to improve psoriasis in a SCID mouse-human skin model and to suppress referred mechanical hypersensitivity and neuropeptide up-regulation associated with acute pancreatitis.

NDT 9513727 is small molecule, orally bioavailable, selective, and potent inverse agonist of the human C5aR. NDT 9513727 inhibited C5a-stimulated responses, including guanosine 5’-3-O-(thio)triphosphate binding, Ca2+ mobilization, oxidative burst, degranulation, cell surface CD11b expression and chemotaxis in various cell types. NDT 9513727 has been shown to effectively inhibit C5a-induced neutropenia in gerbil and cynomolgus macaque in vivo. These results suggest that NDT 9513727 is a promising candidate for the treatment of human inflammatory diseases.

N-MPPP HYDROCHLORIDE is high-affinity κ agonist with no measured binding at μ or δ sites.

RO-20-1724 is a potent inhibitor of Phosphodiesterase 4 (PDE4) originally developed by Roche. It showed some promise as a potential treatment for psoriasis, but it was discontinued when it could not match the efficacy of existing treatments. RO-20-1724 was also investigated as a potential treatment for asthma and septic shock.