Tucaresol, a substituted benzaldehyde, was being developed by Glaxo Wellcome for the prevention of sickle cell disease. Tucaresol was designed to interact with haemoglobin to increase oxygen affinity and has been shown to inhibit sickling in vitro. Tucaresol is also a low-molecular-weight compound that enhances co-stimulatory signaling to CD4 cells. Immune induction is dependent on transient covalent bonding (Schiff base formation) between carbonyls and amines expressed on antigen presenting cell (APC) and T-cell surfaces. Tucaresol substitutes for the natural donor of carbonyl groups to mimic the transient bonding that is essential for T-cell activation. In preliminary studies, tucaresol has been shown to stimulate HIV-specific cytotoxic T lymphocyte responses and generation of naive T cells via thymopoiesis in patients receiving ART who have suppressed viremia. Tucaresol appears to specifically increase type 1 cytokine production. Tucaresol has been used in trials studying the treatment of HIV infections. However, the development of tucaresol for HIV, Hepatitis B and sickle cell diseas treatment has been discontinued.

Nafazatrom [BAY G 6575] is a leukotriene synthesis inhibitor that was being developed by Bayer in Germany. It is a pyrazolinone derivative with potential antimetastatic activities. Nafazatrom, originally developed as an antithrombotic agent, inhibits the key prostaglandin catabolic enzyme, 15-hydroxyprostaglandin dehydrogenase, which prolongs the biological half-life of prostacyclin (prostaglandin I2; PGI2) and prevents intravascular coagulation. Nafazatrom, in the micromolar range, inhibits the metabolism of PGs (prostaglandins) by 15-OH PGDH in a dose-dependent manner. The IC50 for inhibition of 15-OH PGDH was estimated to be 18.5 uM when [3H]PGF2 alpha was used as substrate. This agent also serves as a reducing cofactor with the hydroperoxidase moiety of cyclooxygenase and accelerates the conversion of arachidonic acid into precursors of PGI2. An elevated level of PGI2 prevents aggregation of platelets; subsequently it decreases the formation of tumor cell-platelet aggregates as well as their sequestration in blood vessels, which is an important initiating step in the development of metastasis. Nafazatrom may have had potential as an antithrombotic, anti-ischaemic and antiasthmatic agent. However, the development of nafazatrom was discontinued.

Minepentate was developed as an antiparkinsonian drug. However, it has never been marketed.

Pamicogrel is a cyclooxygenase inhibitor with platelet anti-aggregatory properties which is under development by Kanebo for chronic arterial occlusion. It also has potential in both prophylaxis and treatment of ischemic brain injury. An NDA was submitted in Japan in April 1997. The effects of the drug on platelet aggregation were originally disclosed in EP-00159677, while the later European patent, EP-00560136, claims its use in brain dysfunction induced by hypoxia arising from disturbance of cerebral circulation, such as cerebral hemorrhage or cerebral infarction.

Beloranib (also known as ZGN-433 or CKD-732), a fumagillin anticancer drug that initially was developed by CKD Pharmaceuticals for the treatment of solid tumors. Beloranib is a potent inhibitor of methionine aminopeptidase 2 (MetAP2), an enzyme that modulates the activity of key cellular processes that control metabolism. This drug was studied for the treatment of Prader-Willi syndrome and obesity caused by hypothalamic injury, including craniopharyngioma-associated obesity and severe obesity in the general population. European Commission has granted orphan drug designation for beloranib for the treatment of craniopharyngioma, a rare form of benign brain tumor and for the treatment of Prader-Willi syndrome. Beloran participated in phase III clinical trials to evaluate efficacy and safety in obese adolescent and adult subjects with Prader-Willi Syndrome, but these studies were terminated. In 2016, Zafgen, the company developed the drug, based on discussions with the regulatory authority and review of obstacles, costs and development timelines to gain marketing approval for beloranib, has decided to discontinue further development of the drug.

Nogalamycin is an unusual anthracycline antineoplastic antibiotic isolated from the bacterium Streptomyces nogalater. Nogalamycin intercalates into DNA and interacts with topoisomerase I, thereby inhibiting DNA replication and repair and RNA and protein synthesis. Nogalamycin contains two saccharides. The neutral monosaccharide attaches to the D ring, similar to the aminoglycoside moieties of the doxorubicin class, while the second, basic saccharide attaches to the phenolic group on the A ring in the ortho position to form a unique family of hexacyclic anthracyclines. Nogalamycin is potent antibacterial and antitumor agent. Nogalamycin was markedly cytotoxic in vitro and was active against several tumor systems in vivo.

Indantadol (previously known as CHF-3381) is an oral and noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist and reversible monoamine oxidase-A (MAO-A) inhibitor that is being developed by Vernalis plc, under license from Chiesi Farmaceutici SpA, for the potential treatment of neuropathic pain. In preclinical studies, indantadol exhibited neuroprotective effects after kainate-induced seizures and displayed anticonvulsant and antihyperalgesic activity. Indantadol also caused a dose-dependent decrease in exploratory motility. In a human heat-capsaicin-induced pain model, indantadol at a dose of 500 mg effectively reduced the area of secondary hyperalgesia. The tolerability profile of the drug at single doses up to 600 mg and twice-daily doses up to 400 mg in clinical trials was significantly more favorable than for other NMDA antagonists. Most side effects have been observed to be mild, and include dizziness and asthenia. Indantadol was in phase II clinical trials for the treatment of chronic cough and neuropathic pain. However, these studies had been discontinued.

Terikalant is a benzopyran derivative patented by Rhone-Poulenc Sante as an antiarrhythmic agent. In normal cardiac tissues studied in vitro, Terikalant dose-dependently prolonged the atrial and ventricular action potential but affected neither the upstroke of the action potential nor the diastolic potential. Patch-clamp experiments demonstrated that the prolongation of the action potential induced by Terikalant is due to a specific blockade of the inward rectifier K+ current. In vivo, i.v. administration to anesthetized dogs of low doses of Terikalant consistently induced bradycardia and prolonged the atrial, nodal, and ventricular refractory periods, but did not affect the conduction velocity.