Otenabant (CP-945,598) is Pfizer developed as a potent and selective cannabinoid receptor CB1 antagonist with Ki of 0.7 nM, which exhibits 10,000-fold greater selectivity against human CB2 receptor, for treatment of obesity. In clinical trial III Pfizer decided to discontinue the development program based on changing regulatory perspectives on the risk/benefit profile of the CB1 class and likely new regulatory requirements for approval.

Etazolate (EHT-0202) is a selective, positive GABAA receptor modulator has completed phase II clinical trials in patients with Alzheimer's disease. It is also a selective phosphodiesterase-4 inhibitor that is specific for cAMP. Etazolate showed anxiolytic and antidepressant activity and could be useful in managing post-traumatic stress disorder.

The BET-bromodomain inhibitor OTX015 (MK-8628) was initially developed by Mitsubishi Tanabe Pharma Corporation, but then was licensed by OncoEthix, privately held biotechnology company. OTX015 is a selective bromodomains: BRD2, BRD3, and BRD4 inhibitor and inhibits their binding to AcH4. Bromodomains have an important role in the targeting of chromatin-modifying enzymes to specific sites, including methyltransferases, HATs and transcription factors and regulate diverse biological processes from cell proliferation and differentiation to energy homeostasis and neurological processes. OTX015 has potent antiproliferative activity accompanied by c-MYC down-regulation in several tumor types, and has demonstrated synergism with the mTOR inhibitor everolimus in different models. Oral administration of OTX-015 markedly inhibited tumor growth and reduced tumor volume. OTX015 is currently in Phase 1b studies for the treatment of hematological malignancies and advanced solid tumors such as Triple Negative Breast Cancer, Non-small Cell Lung Cancer, Castrate-resistant Prostate Cancer (CRPC) and Pancreatic Ductal Adenocarcinoma. In addition, OTX015 was in phase II for the treatment of Glioblastoma Multiforme, but there were not detected clinical activity of the drug in the treatment populations and trial was closed.

Tarenflurbil (Flurizan or R-flurbiprofen) is the single enantiomer of the racemate NSAID flurbiprofen. Tarenflurbil is a first in class, selective amyloid-beta42 (A42) lowering agent (SALA), which acts by modulating the activity of gamma-secretase, an enzyme that converts amyloid precursor protein to amyloid-beta. The reduction of A42 may prevent the development of the amyloid plaques thought to be a key pathological process associated with Alzheimer’s disease. For several years, research and trials for the drug were conducted by Myriad Genetics, to investigate its potential as a treatment for Alzheimer's disease. In a brief statement issued June 30, Myriad Genetics reports that tarenflurbil (Flurizan) failed to have a significant effect in a phase 3 trial of patients with mild Alzheimer's disease (AD). The failure of Flurizan™ is generally attributed to its insufficient pharmacodynamics, i.e., inadequate ability to penetrate the brain and engage its target protein at doses sufficient to yield an effect. Two additional Phase 3 trials were terminated and further development of Flurizan™ was discontinued. Separate clinical development of Flurizan™ for prostate cancer has also been discontinued following negative Phase 2 results. Tarenflurbil activates c-Jun N terminal kinase, increases AP-1 binding to DNA, and downregulates cyclin D1 expression, resulting in the arrest of tumour cells in the G1 phase of the cell cycle and apoptosis. This agent also affects the expression of nuclear factor kappa B, a rapid response transcription factor that stimulates the immune response to tumour cells. Tarenflurbil does not inhibit the enzyme cyclooxygenase. The Fraunhofer Institute for Molecular Biology and Applied Ecology is currently developing tarenflurbil for the treatment of relapsing, remitting multiple sclerosis.

Danusertib is a serine/threonine kinase inhibitor of multiple kinases, including aurora-A, B, and C. It also inhibits several cancer related tyrosine kinases as well as Abl, Trk-a, fibroblast growth receptor-1 and Ret. Danusertib is in phase II trials for the treatment of solid tumours, prostate cancer and chronic myeloid leukemia (CML). The most frequently reported side effects were neutropenia, nausea, anorexia, fatigue, and diarrhea.

Dacinostat (also known as LAQ824), is a hydroxamate histone deacetylase inhibitor with potential anticancer activity. Dacinostat inhibits histone deacetylase enzymatic activities in vitro and transcriptionally activated the p21 promoter in reporter gene assays. Tumor cells treated with Dacinostat caused acetylation of HSP90 and degradation of its cargo oncoproteins. Flow cytometry studies revealed that both tumor cell lines and normal diploid fibroblasts arrested in the G2/M phase of the cell cycle after Dacinostat treatment. However, an increased sub-G1 population at 48 h (reminiscent of apoptotic cells) was only observed in the cancer cell lines treated with Dacinostat. Dacinostat exhibited antitumor effects in a xenograft animal models. In phase I trials, Dacinostat was well tolerated at doses that induced accumulation of histone acetylation, with higher doses inducing changes consistent with HSP90 inhibition. In another phase 1 in patients with advanced solid tumors, grade 3 or 4 toxicities were observed. Dacinostat had been in phase II clinical trials by Novartis for the treatment of solid tumors but further studies were discontinued.

Hydroxyflutamide is the major active metabolite of flutamide. Flutamide undergoes extensive first-pass metabolism by CYP1A2 to its metabolite hydroxyflutamide and its hydrolysis product, 3-trifluoromethyl-4-nitroaniline. Hydroxyflutamide is a more powerful antiandrogen in vivo, with higher affinity for the receptor than that of flutamide. Hydroxyflutamide is in phase II clinical trials for the treatment of prostate cancer. However, a drug resistance problem appears after about one year's treatment. Per-residue free energy decomposition analyses indicate that N705, T877, and M895 androgen receptor mutations are vital residues in the agonist/antagonist mechanism of hydroxyflutamide.

Plinabulin (formerly known as NPI-2358) is a potent microtubule-destabilizing agent that exerts its effect by binding to the colchicine-binding site of tubulin. Plinabulin projects its potent antitumor activity against a broad spectrum of tumor cell lines. This drug in combination with docetaxel is under development by BeyondSpring Pharmaceuticals in a worldwide Phase 3 clinical trial for non-small cell lung cancer. Pegfilgrastim is also in phase II clinical trial for the prevention of chemotherapy-induced neutropenia, where docetaxel, doxorubicin, and cyclophosphamide (TAC) were used as the chemotherapy. Plinabulin also possessed antitumor activity in animal models with multiple myeloma cancer cells, where the JNK protein appeared to be a primary target of plinabulin.

AstraZeneca (formerly Astra) is developing robalzotan (NAD-299, AZD-7371), a 5-HT1A antagonist, for the potential treatment of depression and anxiety. The compound has entered phase II trials but was discontinued. Then it investigated for the treatment of irritable bowel syndrome, but the study was prematurely terminated. The same final has expected the development of robalzotan in phase II to treat overactive bladder, this investigation was terminated in July 2005.

Zaurategrast (CDP323) is an ethyl ester prodrug of CT7758, a potent carboxylic acid antagonist of integrin alpha4-beta1 (α4β1) or very late antigen 4 (VLA4). CDP323 was under development with UCB and Biogen Idec for the treatment of multiple sclerosis. Its development was discontinued in 2009 based on inadequate interim efficacy data in a phase II clinical trial.