Ritanserin (INN, USAN, BAN) is a serotonin receptor antagonist which was never marketed for clinical use but has been used in scientific research. In humans, ritanserin increases deep slow-wave sleep, improved liveliness in a variety of psychiatric disorders and facilitated participation in behaviour therapy. During clinical trials, unexpected observations indicated that ritanserin may be of value in treating obsessive-compulsive disorder, acute mania, negative symptoms of schizophrenia, drug addicts, etc. Clinical observations confirmed the efficacy of ritanserin in the chronic withdrawal phase after detoxification from ethanol. Ritanserin had been in phase III clinical trials by Janssen L.P. for the treatment of anxiety disorder and major depressive disorder. However, the clinical development of ritanserin was discontinued.

Entospletinib (GS-9973) is an adenosine triphosphate competitive inhibitor of Syk that disrupts kinase activity, which is currently in clinical trials for multiple B-cell malignancies. The most common treatment-emergent serious adverse events included dyspnea, pneumonia, febrile neutropenia, dehydration, and pyrexia.

Entospletinib (GS-9973) is an adenosine triphosphate competitive inhibitor of Syk that disrupts kinase activity, which is currently in clinical trials for multiple B-cell malignancies. The most common treatment-emergent serious adverse events included dyspnea, pneumonia, febrile neutropenia, dehydration, and pyrexia.

Inaperisone is a pyrrolidinopropiophenone derivative patented by Japanese pharmaceutical company Hokuriku Pharmaceutical Co. as muscle-relaxant and antispasmodic agent.

Azabyperone was developed as tranquilizer and neuroleptic and has never been marketed.

LY-3039478 is an orally bioavailable, novel small molecule inhibitor of Notch signaling pathway, developed Eli Lilly and Company for cancer treatment. The Notch receptor, on the surfaces of progenitor cells and cancer cells, binds neighboring cell-surface ligands DLL or JAGGED. On ligand binding, the intramembrane protease γ-secretase cleaves the Notch intracellular domain (NICD). LY-3039478 is an exquisitely potent inhibitor of Notch-1 intracellular domain (N1ICD) cleavage with an IC50 of ∼1nM in most of the tumor cell lines tested. LY3039478 also potently inhibits mutant Notch receptor activity. Treatment with a gamma-secretase inhibitor, LY3039478, significantly inhibited the growth of 2 CCRCC(Clear cell renal cell carcinoma) cell lines in a concentration-dependent manner. LY3039478 treatment also led to decreased expression of Myc and Cyclin A1, two genes that were part of the NOTCH driven proliferative signature in murine and human model systems. LY3039478 treatment also led to G0/G1 cell cycle arrest in CCRCC cells. In a xenograft tumor model, LY3039478 inhibited N1ICD cleavage and expression of Notch-regulated genes in the tumor microenvironment. The inhibition of Notch cleavage also resulted in the induction of apoptosis in a Notch-dependent xenograft model. In immunodeficient NSG mice xenografted with 769-P CCRCC cells, LY3039478 treatment resulted in significantly increased survival and delayed tumor growth in independent cohorts of mice demonstrating in vivo efficacy in CCRCC. LY3039478 is being investigated in a clinical trial in patients with T-cell acute lymphoblastic leukemia or T-cell lymphoblastic lymphoma in combination with Dexamethasone.

Flurocitabine is an anti-metabolite that was developed by Hoffmann-La Roche for the treatment of cancer. The drug is metabolized to 2 biologically active substances, AFC (1-beta-D-arabinofuranosyl-5-fluorocytosine) and AFU (arabinofuranosyl-5-fluorouracil). Flurocitabine was tested against stomach cancer, pancreatic cancer, small cell lung cancer and AML, however, the development was terminated in the early phases.

Timelotem is a benzodiazepine derivative patented by Kali-Chemie Pharma G.m.b.H. as an anesthetic agent. In preclinical models, Timelotem shows atypical antipsychotic activity. Timelotem antagonizes DL-2-amino-5-phosphonovaleric acid (AP-5)-induced sniffing and the body turns in rats. Further, Timelotem antagonized amphetamine-induced stereotyped behavior in rats but was found less active than haloperidol in this test.

Esmirtazapine (S-(+)mirtazapine or ORG-50081) is an enantiomer of mirtazapine (REMERON®), a high-affinity antagonist at 5-HT2/5-HT3 and H1 receptors, used in the treatment of depression. Esmirtazapine has a shorter plasma half-life than the R(−) enantiomer. Esmirtazapine is preferentially metabolized into an 8-hydroxy glucuronide. Organon was developing esmirtazapine for the treatment of hot flushes (vasomotor symptoms) associated with the menopause and insomnia.

Esmirtazapine (S-(+)mirtazapine or ORG-50081) is an enantiomer of mirtazapine (REMERON®), a high-affinity antagonist at 5-HT2/5-HT3 and H1 receptors, used in the treatment of depression. Esmirtazapine has a shorter plasma half-life than the R(−) enantiomer. Esmirtazapine is preferentially metabolized into an 8-hydroxy glucuronide. Organon was developing esmirtazapine for the treatment of hot flushes (vasomotor symptoms) associated with the menopause and insomnia.