Safingol, the synthetic L-threo-stereoisomer of endogenous (D-erythro-) sphinganine, is an inhibitor of protein kinase C and sphingosine kinase in vitro, and in some cell types has been implicated in ceramide generation and induction of apoptosis. Safingol inhibits enzymatic activity and 3H-phorbol dibutyrate binding of purified rat brain PKC (IC50 = 37.5 uM and 31uM, respectively). Inhibits human PKCα, the major overexpressed isoenzyme in MCF-7 DOXR cells (IC50 = 40 uM). Safingol enhances the cytotoxic effect of the chemotherapeutic agent Mitomycin C (MMC) in gastric cancer cells by promoting drug-induced apoptosis. Safingol is an inhibitor of SphK (Sphingosine kinase). Safingol has been shown to act synergistically with other chemotherapeutic agents and may potentiate chemotherapy drug-induced apoptosis in vitro and in vivo.

OPINIAZIDE (also known as saluzid) was used for the treatment of meningeal tuberculosis in adults and in children. Information about the current use of this drug is not available.

R-etodolac (SDX-101) is the non-cyclooxygenase 2-inhibiting R-enantiomer of the non-steroid anti-inflammatory drug etodolac (1,8-diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetic acid). The absolute configuration of the enantiomer is R-(-)-etodolac. R-etodolac specifically bound retinoid X receptor (RXRalpha), inhibited RXRalpha transcriptional activity, and induced its degradation by a ubiquitin and proteasome-dependent pathway. In addition R-etodolac can disrupt the beta-catenin signaling pathway. R-etodolac exerts antineoplastic properties. R-etodolac was in phase 2 studies for the treatment of hematologic malignancies however development was discontinued.

Cobristone is a locally acting chloride channel activator that works to stimulate and protect the mucosal barrier function. Cobristone is being developed by the Sucampo Pharmaceuticals, Inc. for the prevention of oral mucositis and for the treatment of non-erosive reflux disease (NERD), a major subtype of gastroesophageal reflux disease. The development of the drug was terminated after phase 2 clinical trials failed to meet its primary endpoints.

Salclobuzate sodium was developed as an oral absorption promoter. This compound had to “chaperone” poorly permeable payloads across the intestine. Information about the current use of this compound is not available.

AstraZeneca developed disufenton (NXY-059), a free radical trapping agent, for the treatment of ischaemic stroke and other brain injuries. Nevertheless, large clinical trial (3306 versus 1722 patients) was neutral, providing no evidence for the efficacy of disufenton sodium in patients with stroke. One study using rat cortical brain slices concluded that NXY-059 improved neuronal survival. However, another study in mouse neuroblastoma cells reported no effect. Another study reported that NXY-059 restored endothelial blood-brain. Histological analyses revealed several therapeutic advantages associated with disufenton sodium treatment following acute acoustic trauma, including reductions in inner and outer hair cell loss; reductions in acute acoustic trauma-induced loss of calretinin-positive afferent nerve fibers in the spiral lamina; and reductions in fibrocyte loss within the spiral ligament. However, AstraZeneca terminated the development program.

Nicoxamat (nicotinohydroxamic acid) is a uricosuric drug that increased urinary excretion of urea and depressed urease activity in the stomach and the colon. Patients receiving nicoxamat showed significant improvement in blood ammonia levels as compared to patients receiving neomycin. In a double-blind clinical trial, 24 patients with the advanced chronic liver disease received 1.2 g of the drug daily. Nicoxamat induced some side effects, such as mild diarrhea, constipation, and anorexia.

Elesclomol (also known as STA-4783), originally identified in a cell-based phenotypic screen for pro-apoptotic activity, is a novel small-molecule that potently induces apoptosis of cancer cells through the rapid generation of reactive oxygen species (ROS) and the induction of unmanageable levels of oxidative stress. Elesclomol exhibits antitumor activity against a broad spectrum of types of cancer cell in human tumour xenograft models due to its excessive ROS production and elevated levels of oxidative stress leading to the death of cancer cells. Elesclomol is currently being studied as novel cancer therapeutic, in which it has demonstrated the ability to prolong progression-free survival in study subjects. Elesclomol induces oxidative stress by provoking a buildup of reactive oxygen species within cancer cells. Elesclomol requires a redox-active metal ion to function; the Cu(II) complex is 34 times more potent than the Ni(II) complex and 1040-fold more potent than the Pt(II) complex. Elesclomol is an HSP-90 Inhibitor with pro-apoptotic and potential antineoplastic activities. Elesclomol induces oxidative stress and triggers mitochondrial-induced apoptosis in cancer cells. Elesclomol is being developed by Synta Pharmaceuticals and GlaxoSmithKline as a chemotherapy adjuvant and has received both fast track and orphan drug status from the U.S. Food and Drug Administration for the treatment of metastatic melanoma. Synta Pharmaceuticals announced on February 26, 2009, the suspension of all clinical trials involving Elesclomol due to safety concerns. In March 2010, Synta announced that the FDA had approved resuming clinical development of elesclomol, and that they expected to initiate one or more clinical trials for elesclomol in the second half of the year. In a small, randomized phase II study, elesclomol was shown to significantly increase progression-free survival in people with metastatic melanoma when given in addition to paclitaxel (Taxol).