PF-04418948 is an orally active, potent, and selective EP2 receptor antagonist. It is used as a tool compound to study involvement of EP2 receptor in various pathologies. In combination with EP4 antagonist, PF-04418948 attenuates PGE2-induced airway microvascular leak in model of asthma, and PGE2-induced gut dismotility.

Primaperone is substituted amino ketone patented by Science-Union et Cie.-Societe Francaise de Recherche Medicale as hypotensive and tranquilizing agents. Primaperone acts as serotonin receptor antagonis and demonstrate activity in behavioral despair test

NPV-LEQ506 is an orally bioavailable small-molecule Smoothened (Smo) antagonist with potential antineoplastic activity. NPV-LEQ506 selectively binds to the Hedgehog (Hh)-ligand cell surface receptor Smo, which may result in the suppression of the Hh signaling pathway, thereby inhibiting tumor cell growth. NPV-LEQ506 is a second-generation inhibitor of smoothened (Smo) with IC50s of 2 and 4 nM in human and mouse, respectively. NPV-LEQ506 has been in clinical trials with Novartis studying the treatment of advanced solid tumors, recurrent or refractory medulloblastoma, and locally advanced or metastatic basal cell carcinoma.

OC-459 is a highly potent and selective CRTH2 antagonist which is active on both the recombinant and native human receptor. The Atopix lead compound OC-459 is effective in improving lung function and symptoms in patients with atopic eosinophilic asthma. This group represents 40-50% of all asthmatics and the magnitude of improvement in the responder population is equivalent to high dose inhaled corticosteroids. OC-459 has also been shown to reduce both nasal and eye symptoms in allergic subjects exposed to grass pollen. Of particular interest is the ability of OC-459 to reduce the rate of respiratory infections, an effect related to reduction in Th2 immunity which has a damaging effect on host defence. OC-459 has also demonstrated an excellent safety profile in around 800 subjects exposed drug and no safety issues have been highlighted in long term toxicology. OC-459 is in Phase 2 clinical trial in patients with moderate to severe atopic dermatitis.

MK-0812 is a potent and selective CCR2 antagonist, which was developed by Merck. This drug has entered clinical trials for both rheumatoid arthritis and multiple sclerosis. However, the rheumatoid arthritis trial was terminated because of lack of favorable outcomes when MK-0812 failed to show any early clinical improvement. The outcome of the multiple sclerosis trial of MK-0812 also had negative outcomes.

Batefenterol, previously known as GSK961081, a bifunctional muscarinic (M2 and M3 receptors) antagonist β2-agonist that is developed for chronic obstructive pulmonary disease (COPD). The drug has successfully completed phase II clinical trials with clinically significant improvements in lung function. No new or unexpected safety signals were observed in this COPD population. The conclusion from the trial was following that batefenterol 300 µg might represent the optimal dose for Phase III studies.

Nolpitantium (SR-140333) is a highly selective nonpeptide antagonist of neurokinin-1 (NK1) receptor. Nolpitantium potently, selectively and competitively inhibited substance P binding to NK1 receptors from various animal species, including humans. In vitro, it was a potent antagonist in functional assays for NK1 receptors such as [Sar9, Met(O2)11]substance P-induced endothelium-dependent relaxation of rabbit pulmonary artery and contraction of guinea-pig ileum. Up to 1 mkM, Nolpitantium had no effect in bioassays for NK2 and NK3 receptors. The antagonism exerted by Nolpitantium toward NK1 receptors was apparently non-competitive, with pD2' values between 9.65 and 10.16 in the different assays. Nolpitantium also blocked in vitro [Sar9, Met(O2)11]substance P-induced release of acetylcholine from rat striatum. In vivo, Nolpitantium exerted highly potent antagonism toward [Sar9, Met(O2)11]substance P-induced hypotension in dogs, bronchoconstriction in guinea-pig) and plasma extravasation in rats. Nolpitantium was found to be effective in the modulation of the inflammatory response and airway remodeling in mice. Nolpitantium is reported to cause antagonism of the SP-induced relaxations of human isolated intralobar pulmonary arterial rings. Nolpitantium also blocked the activation of rat thalamic neurons after nociceptive stimulation. Nolpitantium has been shown to reduce the severity of inflammation in trinitrobenzene sulfonic acid-induced colitis in the rat colon. Nolpitantium inhibited mustard oil-induced plasma protein extravasations in the dorsal skin of the rat hind paw. Nolpitantium had been in some phase II clinical trials but further studies were discontinued.

SB-705498 is a selective vanilloid receptor-1 (VR1/TRPV1) antagonist developed by GlaxoSmithKline. The drug was tested in phase II of clinical trials for the treatment of pain (dental, rectal, in migraine) and rhinitis/cough. The development of the drug has been terminated by unknown reason (SB-705498 is no longer in GSK pipeline).

5-((4-(6-Chlorothieno[2,3-d]pyrimidin-4-ylamino)piperidin-1-yl)methyl)-2-fluorobenzonitrile monofumarate (PRX-08066) is a selective 5-hydroxytryptamine receptor 2B (5-HT2BR) antagonist that causes selective vasodilation of pulmonary arteries. This drug was discovered and developed by Predix (later Epix) Pharmaceuticals and is being researched for the treatment of pulmonary arterial hypertension. In animal studies, PRX-08066 has been found to reduce several key indicators of pulmonary arterial hypertension and improved cardiac output, with similar efficacy to established drugs for this condition such as bosentan, sildenafil, beraprost and iloprost.

LY377604 is a human β3-adrenergic receptor agonist and β1- and β2-adrenergic receptor antagonist with no sympathomimetic activity at the β1- and β2-adrenergic receptors. Combination of LY377604 and a norepinephrine-serotonin uptake inhibitor (sibutramine) was studied in the treatment of obesity. LY377604 would ameliorate side effect of sibutramine treatment (increase in blood pressure and heart rate due to activation of the sympathetic nervous system).