Trichostatin A (TSA) was originally isolated as an antifungal antibiotic along with its fermentation congeners trichostatin B ((TSA)3-Fe) and the D-glucopyranosides trichostatin C and D. TSA inhibits HDAC in the low nanomolar range and is an inducer of histone hyperacetylation, both in vitro and in vivo. It inhibits all class I and II deacetylases to a similar extent in both tumor and non-tumor cells, although HDAC4 is slightly resistant when compared with HDAC1 and HDAC6. Class III HDAC is not affected by TSA. It has been shown that TSA dosedependently inhibits growth and induces apoptosis in a plethora of carcinoma cell lines in vitro. Recently, it was also found that TSA inhibits angiogenesis, which is important for the growth and metastasis of solid tumors, both in vivo and in vitro. In HT-29 colon carcinoma cells, a single dose of TSA induced transient hyperacetylation of histone H4 resulting in the induction of p21WAF1/Cip1 and inhibition of cellular proliferation at both the G1 and G2 phases of the cell cycle. Growth inhibition was associated with decreased cyclin D1 mRNA and cdk6 protein levels and increased cyclin D3 protein and p21WAF1/Cip1 mRNA levels. Cyclin D1 protein, cyclin D3 mRNA, cdk2 and cdk4 remained unaffected. In addition, TSA induced apoptosis by upregulating the expression of the pro-apoptotic genes ID1, ID2 and ID3, whereas the expression of the anti-apoptotic genes BclxL and Hsp27 was decreased In vivo, TSA induces differentiation and shows chemotherapeutic activity against N-methylnitrosureainduced rat mammary cancer without toxic side effects. TSA may also have therapeutic potential for the treatment of a variety of genetic and infectious diseases since silenced, transduced genes are reactivated probably due to structural changes of the chromatin on integrated viral sequences.

Oxi0-4503 (now known as combretastatin A1 phosphate), a diphosphate prodrug of combretastatin A1, was developed by Mateon therapeutics as a second-generation, dual-mechanism vascular disrupting agent from the combretastatin family. On November 21, 2012, Oxi-4503 has been granted orphan designation by the US Food and Drug Administration for the treatment of acute myelogenous leukemia. It is known that the orphan drug designation qualifies a company for several benefits, including the potential for market exclusivity, development grants, and tax credits. Oxi0-4503 is currently participating in phase I/II clinical trial the treatment of patients with acute myelogenous leukemia or myelodysplastic syndrome. In addition, phase I clinical trial was successfully completed where was studied the safety of Oxi0-4503 in patients with advanced solid tumors.

Brilacidin (formerly PMX-30063) is a polymer-based antibiotic and an investigational new drug, that was studied in human clinical trials, and represents a new class of antibiotics called host defense protein mimetics. Brilacidin is an antibiotic that works by disrupting bacterial cell membranes, mimicking defensins that play a role in innate immunity. Brilacidin has shown great efficacy in phase II clinical trials against acute Staphylococcus aureus skin and skin structure infections, comparable to that of the lipopeptidic drug daptomycin, which is currently used clinically to treat drug-resistant staph infections. Brilacidin also has potent broad-spectrum activity in vitro against several other Gram-positive and Gram-negative pathogenic bacteria, including several multidrug-resistant strains.

AFN-1252 (now known as Debio-1452) is an antibiotic drug which is in phase II of clinical trials for the treatment of Staphylococcal skin and skin structure infections. The drug was effective in vitro against all isolates of S.aureus and its effect was explained by inhibition of enoyl-acyl carrier protein Reductase (FabI).

PF-04447943 is a potent, selective brain penetrant PDE9 inhibitor (Ki of 2.8, 4.5 and 18 nM) for human, rhesus and rat recombinant PDE9 respectively and high selectivity for PDE9 versus PDEs1-8 and 10-11. PF-04447943 was being developed by Pfizer for the treatment of cognitive disorders. PF-04447943 attenuates a scopolamine-induced deficit in a novel rodent attention task. PF-04447943 enhances synaptic plasticity and cognitive function in rodents. PF-04447943 has completed Phase II clinical trials in subjects with mild to moderate AD in 2013 but this research was discontinued. Pfizer completes a phase I trial in Sickle cell anaemia.

Parafluorofentanyl is a selective mu-opioid agonist, an analog of fentanyl, developed by Janssen. The drug was not developed for human use but is produced and abused illegally.

Norlevorphanol is the levo-isomer of 3-hydroxymorphinan (morphinan-3-ol). It is is an opioid analgesic of the morphinan family. Norlevorphanol is a Schedule I controlled substance (opiate).

10-Hydroxycamptothecin (10-HCPT), an indole alkaloid isolated from a Chinese tree, Camptotheca acuminate, inhibits the activity of topoisomerase I and has a broad spectrum of anticancer activity in vitro and in vivo. However, its use has been limited due to its water-insolubility and toxicity with i.v. administration. Prolonged elimination of 10-HCPT in vivo may have a significant impact on its therapeutic effects. 10-HCPT is metabolized to its carboxylate form and glucuronides.It was investigated that relatively low dose of 10-HCPT is able to inhibit the growth of colon cancer, facilitating the development of a new protocol of human trials with this anticancer drug.

Ezlopitant (CJ-11974) is a non-peptide neurokinin-1 receptor antagonist. Pfizer was developing ezlopitant for the potential treatment of irritable bowel syndrome and chemotherapy-induced emesis. Development of ezlopitant has been discontinued.

Neosaxitoxin is a site-1 specific sodium channel blocker which acts synergistically with local anesthetics to provide surgical anesthesia by peripheral nerve blocks or local infiltration and markedly increases the duration of post-operative analgesia. Saxitoxin and neosaxitoxin, small molecules synthesized by marine dinoflagellates and freshwater cyanobacteria. Neosaxitoxin, one of the saxitoxin analogs, differs from saxitoxin by the addition of one oxygen atom, wherein the hydrogen (-H) at Nitrogen 1 in saxitoxin is replaced by a hydroxyl group (-OH) in neosaxitoxin. Neosaxitoxin has shown greater potency than saxitoxin and its analogs and is also more potent than tetrodotoxin in in vitro and in vivo animal studies.Neosaxitoxin showed an effective local anesthetic effect when injected in the subcutaneous plane. The efficacy of a 50-ug dose of neosaxitoxin was shown. Neosaxitoxin has poor affinity for the cardiac isoform of the sodium channel and does not cross the blood–brain barrier, thus this compound is virtually devoid of cardiac and central nervous system toxicity—the limiting toxicities of traditional local anesthetics.