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.

Squalamine is a steroid-polyamine conjugate compound with broad-spectrum antimicrobial activity and anti-angiogenic activity. Squalamine selectively inhibits new blood vessel formation; this activity is thought to be mediated through inhibition of the sodium-hydrogen antiporter sodium-proton exchangers (specifically the NHE3 isoform) causing inhibition of hydrogen ion efflux from endothelial cells, with subsequent reduction of cellular proliferation. Studies in tumor-bearing mice have shown that squalamine inhibits angiogenesis and tumor growth in xenograft models of lung, breast, ovarian, and prostate cancer and in brain and breast allograft tumor models in rats. Squalamine also has been shown to prevent lung metastases in the murine Lewis lung carcinoma model, both as a single agent and in combination with various other chemotherapeutics. Squalamine does not appear to have substantial direct effects on primary tumor growth in animal models when administered as a single agent. However, enhanced antitumor responses are observed when squalamine is administered in combination with cytotoxic chemotherapeutic agents when compared with cytotoxic agents used alone. Squalamine was studied as a potential cancer drug and as a potential treatment for wet macular degeneration but as of 2018 had not succeeded in Phase III trials for any use.

Misonidazole is a nitroimidazole with radiosensitizing and antineoplastic properties. Exhibiting high electron affinity, misonidazole induces the formation of free radicals and depletes radioprotective thiols, thereby sensitizing hypoxic cells to the cytotoxic effects of ionizing radiation. This single-strand breaks in DNA induced by this agent result in the inhibition of DNA synthesis. The drug also possesses a substantial cytotoxic effect, independent of radiation, which is selectively expressed in hypoxic cells. Misonidazole may be cytotoxic to the normal hypoxic tissues in the human body, making this became a major concern in the clinical application of the drug. Misonidazole leads to strand breaks in cellular DNA and those cells which fail to survive also fail to repair these strand breaks. Misonidazole depletes intracellular glutathione and is more toxic in glutathione depleted cells.

Droloxifene, a derivative of the triphenylethylene drug tamoxifen, is a novel selective estrogen receptor modulator (SERM). Droloxifene also exhibits more rapid pharmacokinetics, reaching peak concentrations and being eliminated much more rapidly than tamoxifen. Its higher affinity to the estrogen receptor, higher anti-estrogenic to estrogenic ratio, more effective inhibition of cell growth and division in estrogen receptor-positive cell lines, and lower toxicity give it theoretical advantages over tamoxifen in the treatment of human breast cancer. Short-term toxicity was generally mild, and similar to that seen with other antiestrogens. Droloxifene appears active and tolerable. It may have a particular role in situations in which rapid pharmacokinetics, or an increased antiestrogenic to estrogenic ratio, are required. Droloxifene may also be a potentially useful agent for the treatment of postmenopausal osteoporosis because it can prevent estrogen deficiency-induced bone loss without causing uterine hypertrophy. Droloxifene may have an effect on bone and breast tissue because it induces apoptosis. Droloxifene has an anti-implantation effect in rats, and the effect appears to be not completely due to its anti-estrogenic activity.

Abarelix is a synthetic decapeptide antagonist to gonadotropin releasing hormone (GnRH). It is marketed by Praecis Pharmaceuticals as Plenaxis. Used in the palliative treatment of advanced prostate cancer. Abarelix is a luteinizing hormone agonist that results in suppression of testicular or follicular steroidogenesis. Abarelix binds to the gonadotropin releasing hormone receptor and acts as a a potent inhibitor of gonadotropin secretion. Praecis announced in June 2006 that it was voluntarily withdrawing the drug from the market.

Suprafen is a dual inhibitor of COX-1 and COX-2, which was used for the inhibition of intraoperative miosis. Suprafen was marketed under the name Profenal, however, it is no longer available in the USA.

Oxypertine (Equipertine, Forit, Integrin, Lanturil, Lotawin, Opertil) is a neuroleptic drug and was originally introduced as a treatment for schizophrenia in the 1960s. Oxypertine is an indole derivative with general properties similar to those of the phenothiazine, chlorpromazine. It has been given by mouth in the treatment of various psychoses including schizophrenia, mania, and disturbed behaviour, and of severe anxiety. Like reserpine and tetrabenazine, oxypertine depletes catecholamines, though not serotonin, possibly underlying its neuroleptic efficacy. The molecular structure is strongly similar to solypertine and milipertine.

Buserelin is a synthetic peptide analog of the luteinizing hormone-releasing hormone (LHRH) agonist, which stimulates the pituitary gland's gonadotrophin-releasing hormone receptor (GnRHR). Buserelin is used for palliative treatment of prostate cancer, and for treatment of endometriosis. Buserelin is also used for infertility treatment to prepare the pituitary gland before starting treatment with gonadotrophins (FSH and LH) to artificially stimulate ovulation.