Levomequitazine is the L-enantiomer of mequitazine. The antihistaminergic activity mainly resides in the S-enantiomer, L-mequitazine, whereas the anticholinergic activity mainly resides in the D-enantiomer. It was shown, that L-enantiomer of mequitazine is less potent antagonist of human M3 muscarinic acetylcholine receptors than D-enantiomer. In vitro binding studies have shown that the affinity of L-mequitazine for H1 receptors is approximately ten times higher and to muscarinic receptors ten times lower, compared to d-mequitazine. Memory impairment was observed after administration of L-mequitazine 10 mg alone on delayed recall. This could be due to indirect effects of H1 receptor blockade. L-mequitazine 10 mg produced mild driving impairment, whereas L-mequitazine 2.5 and 5.0 mg show no effects on driving. Levomequitazine had been in phase III clinical trials by Pierre Fabre for the treatment of perennial allergic rhinitis and seasonal allergic rhinitis.

Bedoradrine (also known as KUR-1246 or MN-221), an ultra selective beta 2-adrenoceptor agonist, that participated in phase II clinical trials as an adjunct to standard therapy in the management of patients with acute exacerbation of asthma who did not respond to standard therapy. In addition, the drug was involved in trials for the treatment of preterm labor in obstetrical practice. Bedoradrine is also was studied in phase I of clinical trials for its use for treating chronic obstructive pulmonary disease, however, the efficacy for this disease was uncertain.

Eprodisate (1,3-propanedisulfonate) is a negatively charged, sulfonated molecule of low molecular weight that has structural similarities to heparin sulfate; it is a glycosaminoglycan mimetic that binds to the glycosaminoglycan (GAG) binding site on serum A amyloid (AA) to prevent its interaction with glycosaminoglycan and arrest amyloidosis, or inhibit amyloid deposition. In nonclinical toxicity studies in two animal species (i.e., rat and dog), eprodisate was administered orally at doses of up to 2000 mg/kg/day for 39 weeks: eprodisate showed low toxicity potential at doses several fold higher than the anticipated clinical dose, was well tolerated upon chronic exposure and was found to be nonmutagenic and nonclastogenic. Furthermore, a series of safety pharmacology studies showed that eprodisate does not have any clinically significant effect on major organ function.

Etonitazene is a potent and selective mu-opioid agonist. It was developed in CIBA. Administration of etonitazene may induce respiratory depression, and therefor etonitazene is not used in humans. Etonitazene is explicitly listed as an illegal drug under UN convention and is illegal throughout the world.

Vatalanib a potent oral tyrosine kinase inhibitor with a selective range of molecular targets, has been extensively investigated and has shown promising results in patients with solid tumors in early trials. Vatalanib selectively inhibits the tyrosine kinase domains of vascular endothelial growth factor (VEGF) receptor tyrosine kinases (important enzymes in the formation of new blood vessels that contribute to tumor growth and metastasis), platelet-derived growth factor (PDGF) receptor, and c-KIT. The adverse effects of vatalanib appear similar to those of other VEGF inhibitors. In the CONFIRM trials, the most common side effects were high blood pressure, gastrointestinal upset (diarrhea, nausea, and vomiting), fatigue, and dizziness.

Begacestat (GSI-953 or PF-5212362), a gamma-secretase inhibitor (GSI) that selectively inhibits cleavage of APP over Notch, was discovered for the treatment of Alzheimer's disease. The drug has shown promise results in phase I clinical trials, however further studies were discontinued.

Ditiocarb, the sodium salt of diethyldithiocarbamate, is a drug with strong antioxidant capacity and chelating activities. It improves the depressed immune responses of newborn and aged mice and mice that are treated with chemotherapy or irradiation. Ditiocarb prevents cisplatin nephrotoxicity in animals without reducing the drug's antitumor activity. Ditiocarb has therapeutic activity in the LP-BM5 murine retrovirus-induced immunodeficiency disease. In that AIDS model, it reduces lymphadenopathy and hypergammaglobulinemia, restores immunocompetence, and prolongs survival. Ditiocarb was safe and reduced the incidence of opportunistic infections in patients with symptomatic HIV infection but ditiocarb had no positive effect on HIV patients. The administration of ditiocarb did not induce any major adverse clinical or biological reactions. Sixty-four patients with nonmetastatic high-risk breast cancer were randomized in a double-blind trial of adjuvant immunotherapy with sodium ditiocarb (DDC) versus placebo. At 6 years, overall survival was 81% in DDC group versus 55%.

IRDABISANT is a histamine H3 receptor inverse agonist with potential therapeutic utility in cognition enhancement.

Cethromycin is a ketolide antibiotic derived from erythromycin A being investigated for use in community-acquired pneumonia and other respiratory tract infections. Cethromycin possesses reliable activity against the bacteria most commonly associated with community-acquired pneumonia including S. pneumoniae, H. influenzae, M. catarrhalis, M. pneumoniae, C. pneumoniae, and L. pneumophila. Unlike fluoroquinolones, cethromycin has a narrower spectrum of activity against gram-negative bacteria, which may reduce the risk of collateral damage and the incidence of Clostridium difficile infection. It offers an advantage over telithromycin in that hepatotoxicity does not seem to be a concern. The FDA denied approval of cethromycin for the treatment of CAP in 2009, requesting more efficacy data.

CI 1040 is an inhibitor of the mitogen-activated protein (MAP) kinase signal transduction pathway and has been shown to specifically inhibit MAP kinase kinase (MEK). CI 1040 was being developed by Parke-Davis (formerly a division of WarnerLambert, Now Pfizer) as an anticancer agent. It was the initial MEK inhibitor to undergo clinical evaluation based on promising preclinical activity. However, its development has been discontinued.