KOS-1584 is a second-generation epothilone D analog designed to have less toxicity, more potency, and higher solubility compared with epothilone D. It has a broad spectrum of potent antiproliferative activity on tumor cells. Currently, KOS-1584 is under clinical evaluation.

Elsamitrucin is a heterocyclic antineoplastic antibiotic isolated from the bacterium Actinomycete strain J907-21. Elsamitrucin intercalates into DNA at guanine-cytosine (G-C)-rich sequences and inhibits topoisomerase I and II, resulting in single-strand breaks and inhibition of DNA replication. It demonstrated a broad spectrum of in vitro cytotoxicity against tumor cell lines. According to the results of Phase II trials elsamitrucin is not an active drug in patients with metastatic breast cancer, colorectal cancer, non-small cell lung cancer or ovarian cancer, however, it showed modest activity in patients with relapsed or refractory non-Hodgkin's lymphoma.

Dexivacaine is a local anesthetic drug that has minimal and non-significant side effects.

Ramifenazone is pyrazolone derivative with analgesic, antipyretic, and anti-inflammatory activity. In preclinical studies, Ramifenazone shows potent inhibition of prostaglandin production, carrageenan edema, and yeast fever.

Gemopatrilat is a vasopeptidase inhibitor, that was found to inhibit plasma and renal angiotensin converting enzyme (ACE), as well as renal neutral endopeptidase (NEP). Gemopatrilat is rapidly absorbed, and causes inhibition of circulating and renal ACE and renal NEP after a single oral dose for up to 48 hours in rats. Potentially, this is because the free sulfhydryl group of gemopatrilat forms reversible disulfide linkages with plasma and tissue proteins and is thus eliminated from the body at a very slow rate. Similar metabolism of the compound was found in rat, dog, and human. Gemopatrilat was evaluated for its potential in treatment of antihypertensive activity in hypertension (independent of age, renin and salt status or ethnic origin), as well as its potential as a new therapeutic modality for the treatment of congestive heart failure. The drug was never marketed. A phase II study for treatment of hypertension and heart failure has been discontinued.

Pibaxizine is diphenylmethyl piperazine derivatives. It is a histamine H1 receptor antagonist. Animal experiments have shown that it has spasmolytic properties for smooth muscle, particularly in the bronchi, as well as anticholinergic and anti-serotonin activities. It can be concluded that Pibaxizine has a strong protective effect against bronchospasm caused by inhalation of a histamine aerosol. Protection against methacholine-induced bronchospasm was less marked. Pibaxizine had been in phase II clinical trial for the treatment of chronic obstructive pulmonary disease. However, this development was discontinued.

Sopromidine is a neuroprotective drug. Sopromidine is a potent and stereoselective isomer of the achiral H2-agonist impromidine. The chiral impromidine isomer sopromidine is of special interest as the (R)-configurated compound behaves as gpH2R agonist, whereas the (S)-configurated counterpart is devoid of agonist activity. Both Sopromidine and its S enantiomer acted as antagonists of histamine at H3-autoreceptors with similar potencies (Ki = 5.6 X 10(-8) M and 4.5 X 10(-8) M), whereas Sopromidine acted as an H2-receptor agonist and the S-enantiomer as an H2-receptor antagonist.

Spirendolol (LI 32-468) is a β adrenergic receptor antagonist. It possesses high affinity for metabolic beta-adrenoreceptors which mediate glycogenolysis that is 100 times more potent than propranolol. In human volunteer studies, a single dose of 2 mg LI 32-468 elicited virtually no cardiac beta-adrenoreceptor blockade (predominantly beta-1), whereas a maximal metabolic beta-adrenoreceptor blocking effect (beta-2) was demonstrated. Spirendolol was a potent inhibitor of ocular beta-adrenoceptors, with a 9-12 fold selectivity over inhibition of beta-adrenoceptors in cardiac tissue. When applied topically, Spirendolol was more effective than timolol in decreasing intraocular pressure in normal albino rabbits.

Spizofurone (also known as AG-629) is a spirobenzofuranone derivative patented by Japan's largest pharmaceutical company Takeda Chemical Industries, Ltd. as the anti-ulcer agent. In preclinical models Spizofurone dose-dependently increase in gastric mucosal blood flow in anesthetized dogs. The reduction in the gastric mucosal blood flow as induced by indomethacin was markedly improved by spizofurone. The topical action of spizofurone was confirmed in an in situ experiment using a stomach flap fixed to a lucite chamber. Spizofurone given orally or i.p. in a dose range of 25-200 mg/kg inhibited indomethacin-induced gastric antral ulcers in rats. Furthermore, spizofurone potentiated the inhibitory effect of prostaglandin E2 on indomethacin-induced gastric antral ulcers. The increase in alkaline secretion in bullfrog duodenal mucosa seen in the presence of spizofurone is mediated, at least in part, by stimulation of endogenous prostaglandins synthesis.

Spiroplatin is a metal drug and analog of the second generation for cisplatin, developed for the treatment of cancer. Spiroplatin induces DNA cross-linking, thereby inhibiting DNA replication and the synthesis of RNA and protein. Initial clinical trials of spiroplatin have shown that it can cause less nausea and vomiting than cisplatin, and can be administered without hydration due to less renal toxicity. However, with increasing doses, the marginal toxicity was both renal and hematologic. In addition, spiroplatin was devoid of significant antitumor effects in advanced ovarian cancer, a disease in which some response can be expected. Based on these data, further development was discontinued.