Batabulin or T138067 (2-fluoro-1-methoxy-4-pentafluorophenylsulfonamidobenzene) covalently and selectively modifies the beta1, beta2, and beta4 isotypes of beta-tubulin at a conserved cysteine residue, thereby disrupting microtubule polymerization. Cells exposed to batabulin become altered in shape, indicating a collapse of the cytoskeleton, and show an increase in chromosomal ploidy. Batabulin is equally efficacious in inhibiting the growth of sensitive and multidrug-resistant human tumor xenografts in athymic nude mice. Batabulin has been in clinical trials for the treatment of cancers (breast cancer, colorectal cancer, glioma, hepatocellular carcinoma, non-small cell lung cancer). It does not have clinical activity in the treatment of colorectal cancer and glioma. Batabulin development was discontinued.

Eliprodil, also known as SL 82-0715, is a non-competitive NMDA glutamate receptor antagonist, which targets the polyamine modulatory site and is selective for NR2B subunit-containing receptors. Eliprodil was in phase III clinical trial for the treatment of stroke or traumatic brain injury. However, these investigations were failed. One reason suggested for failure was that eliprodil had blocked the synaptic transmission mediated by NMDA receptors, hindering neuronal survival. In addition, eliprodil has been studied in phase II clinical trials for the treatment of Parkinson's disease.

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.

Palifosfamide or ZIO-201 (isophosphoramide mustard; IPM), a bi-functional DNA alkylator, is the active metabolite of ifosfamide (IFOS). IFOS and the related drug cyclophosphamide (CPA) are widely used anti-cancer drugs. Both are pro-drugs and need to be metabolized to be active. Their clinical use is limited by the toxicity associated with some of their metabolites. Palifosfamide has shown efficacy in diverse cancer models. ZIOPHARM Oncology Inc, under license from Dekk-Tec Inc, was developing palifosfamide, a formulation of isophosphoramide mustard with tris(hydroxymethyl)aminomethane salt-stabilization (palifosfamide-tris) and previously with lysine-stabilization (palifosfamide-lys). Preclinical studies and phase I and I/II clinical trials demonstrated that palifosfamide-tris had an antitumor efficiency comparable or superior to that of ifosfamide. To date ZIO-201 is not present in ZIOPHARM pipeline.

Veliflapon (BAY X1005, DG-031) is an enantioselective inhibitor of 5-lipoxygenase activating protein, or FLAP. There are variants in the gene encoding FLAP, and the gene encoding leukotriene A4 hydrolase (LTA4H) linked to risk of heart attack. These variants appear to confer increased risk of heart attack by increasing the production of leukotriene B4 (LTB4), a potent driver of inflammation produced in atherosclerotic plaques. deCODE licensed veliflapon (BAY X1005, DG-031) from Bayer AG, which developed it originally for the treatment of asthma.

Saracatinib (AZD0530) is an oral, dual inhibitor of c-Src/Abl kinases initially developed by AstraZeneca for the treatment of cancer. The drug was tested for many neoplasms and reached phase III for ovarian cancer (in combination with paclitaxel), however without demonstrating any significant effect. Sarcatinib is also tested in patients with Alzheimer's Disease (Phase II). Its effect on Alzheimer's Disease patients is explained by inhibition of another kinase, Fyn, which is highly expressed in brain.

Valspodar (PSC-833) is a derivative of cyclosporin but devoid of the immunosuppressive and nephrotoxic properties seen in cyclosporin A. It exhibited high-affinity binding to Mdr1 P-glycoprotein (P-gp) and demonstrated multidrug resistance-reversing activity superior to cyclosporin A and verapamil both in vitro and in vivo. Preclinical and phase I/II clinical data have indicated that plasma levels of PSC-833 with multidrug resistance-reversing activities are achievable. Potent inhibition of intestinal, hepatobiliary and blood-brain barrier P-gp function has been demonstrated. The toxicity profiles of valspodar are acceptable and dose-limited by transient and reversible cerebellar ataxia. It has shown multidrug resistance-modulating activities towards acute myeloid leukemia, multiple myeloma and ovarian cancer in phase I/II clinical trials. However, the company discontinued development of valspodar in April 2001 following disappointing results reported from several multicentre phase III studies.

Darapladib (SB-435495), as reversible inhibitors of lipoprotein-associated phospholipase A(2) (Lp-PLA(2) has been developed and studies for the potential treatment of atherosclerosis. In November 2013, GSK announced that the drug had failed to meet Phase III endpoints in a trial of 16,000 patients with acute coronary syndrome.

Sumanirole is a novel dopamine agonist with high affinity and efficacy at D2 dopamine receptors and has a substantial degree of selectivity for the D2 receptor over other dopamine receptor subtypes. It had been in clinical trials for the treatment of Parkinson’s disease and restless leg syndrome but these studies were terminated for the efficacy reason.

Ranirestat (AS-3201, SX-3030, SX-3202) is an oral aldose reductase inhibitor. (-)-enantiomer (AS-3201) is 10 times more potent in inhibition of the aldose reductase and 500 times more potent in the in vivo activity than the corresponding (+)-enantiomer (SX-3202). Ranirestat is being developed by Dainippon Sumitomo Pharma (formerly Dainippon Pharmaceutical) for the treatment of diabetic complications, primarily diabetic neuropathy. Ranirestat is a well-tolerated front-line inhibitor. It reproducibly exhibits some degree of measurable objective beneficial outcomes in diabetic neuropathy.