LAPAQUISTAT is a squalene synthase inhibitor. It was shown to lower cholesterol levels in several animal models. It was investigated for the treatment of diabetes and hypercholesterolemia, however, its development was discontinued.

Chugai Pharmaceutical is developing a parathyroid 1 receptor agonist called as PCO371. It is known that parathyroid hormone (PTH) is essential for calcium homeostasis and its action is mediated by the PTH type 1 receptor. PCO371 can provide a new treatment option for PTH-related disorders, including hypoparathyroidism. This drug participated in phase I clinical trial in healthy volunteers. However, Chugai Pharmaceutical has terminated this study. No recent reports of the development of PCO371are available.

Semapimod (CNI-1493) is a cytokine inhibitor and synthetic guanylhydrazone mitogen-activated protein kinase blocker, is being developed by Cytokine PharmaSciences as a potential treatment for Crohn's disease and other inflammatory conditions. As of December 2001, a phase I study demonstrating the safety of the compound had been completed and phase II trials for psoriasis and Crohn's disease were ongoing. In April 2003, preclinical and early clinical studies were underway for a variety of indications, including congestive heart failure and pancreatitis. Semapimod inhibits activation of p38 MAPK and NF-κB and induction of cyclooxygenase-2 by TLR ligands, but not by IL-1β or stresses. Semapimod inhibits TLR4 signaling (IC50 ≈0.3 umol) and acts by desensitizing cells to LPS; it fails to block responses to LPS concentrations of ≥5 ug/ml. Semapimod had been in phase II clinical trials by Ferring Pharmaceuticals for the treatment of Crohn's disease. However, this research has been discontinued. Semapimod is in phase I clinical trials for the treatment of autoimmune disorders and inflammation.

Abexinostat (PCI-24781) is a novel, second-generation phenyl hydroxamic acid–based, orally bioavailable HDAC inhibitor that has previously been shown to have activity in vitro and in vivo against a broad array of cancers, including hematopoietic malignancies and bone and soft-tissue sarcomas. Abexinostat is a pan-HDAC inhibitor mostly targeting HDAC1 with Ki of 7 nM, modest potent to HDACs 2, 3, 6, and 10 and greater than 40-fold selectivity against HDAC8. Abexinostat exhibits potent antitumor activity against a variety of tumor cell lines with GI50 ranging from 0.15 uM to 3.09 uM. PCI-24781 also has an antiproliferative effect on HUVEC endothelial cells with GI50 of 0.43 uM. Abexinostat treatment causes dose-dependent accumulation of both acetylated histones and acetylated tubulin in HCT116 or DLD-1 cells, induces expression of p21, and leads to PARP cleavage and accumulation of the γH2AX. It has also shown good tolerability and activity in Phase I and II clinical trials against lymphoma, as well as against solid tumors in Phase-I trials. Additionally, it acts as a potent radiosensitizing agent and is synergistic with cytotoxic chemotherapy, such as doxorubicin in preclinical models.

GlaxoSmithKline (GSK) was developing GSK-239512 as a histamine H3 receptor antagonist/inverse agonist as a monotherapy treatment for subjects with mild-to-moderate probable Alzheimer's disease (AD), multiple sclerosis and Schizophrenia. However, in March 2017, GSK globally discontinued the study of GSK-239512 at phase II.

Fenclonine, also known as p-chlorophenylalanine, is an inhibitor of tryptophan hydroxylase, the enzyme that plays a rate-limiting role in the biosynthesis of serotonin. Fenclonine was studied for the treatment of carcinoid syndrome, but the psychological side effects, prevented for the further development for this use.

Meisoindigo ((E)-1,1'-dimethyl-[3,3'-biindolinylidene]-2,2'-dione) is a derivative of Indigo Naturalis, that has been used in China for chronic myeloid leukemia. In vitro cell line studies have shown that this agent might induce apoptosis and myeloid differentiation of acute myeloid leukemia (AML). Meisoindigo has been a routine therapeutic agent in the clinical treatment of chronic myelogenous leukemia (CML) in China since the 1980s. In phase III clinical trial of Meisoindigo involving 402 patients, it was shown that Meisoindigo was equally efficient for both newly diagnosed and previously treated CML patients after oral administration. The hematological complete response (CR) and partial response (PR) rates, respectively, were 45.0 and 39.3% for newly diagnosed patients and 35.9 and 41.4% for previously treated patients. Meisoindigo was generally well tolerated. The most frequent side‑effects were bone, joint and/or muscle pain of varying degrees when the dosage was more than the suitable one.

Bremazocine, a kappa-opioid agonist has limited potential as a clinical analgesic, however, possesses a possible utility for the therapy of alcohol and drug addiction. It was shown that bremazocine-like drugs could lower intraocular pressure and to minimize ischemic damage, that could be used in the therapy of glaucoma and cardiovascular disease.

Quarfloxin (also known as CX-3543) is a fluoroquinolone derivative patented by Cyclene Pharmaceuticals, Inc. as an antitumor agent. Quarfloxin selectively disrupts nucleolin/rDNA G-quadruplex complexes in the nucleolus, thereby inhibiting DNA polymerase I transcription and inducing apoptosis in cancer cells. CX-3543 was evaluated in phase II clinical studies for the treatment of low or intermediate grade neuroendocrine carcinoma, including carcinoid and islet cell cancer. In 2008, a trial for the treatment of chronic lymphocytic leukemia (CLL) was withdrawn prior to patient enrollment. In 2010, phase I clinical studies for the treatment of solid tumors and for the treatment of lymphoma were terminated upon the observation that the modified dose schedule presented no advantage over previously studies schedule solid tumors/ Cylene discontinued development of quarfloxin in 2010.