DB05448 (PX-12, 1-methyl propyl 2-imidazolyl disulfide) is a small molecule irreversible inhibitor of the redox protein thioredoxin, which has been associated with cancer and tumor growth. DB05448 stimulates apoptosis, down-regulates HIF-1α and vascular endothelial growth factor (VEGF) and inhibits tumor growth in animal models. Since high levels of Trx-1 have been associated with colorectal, gastric and lung cancers, DB05448 is indicated as a potential cancer treatment in combination with chemotherapy for patients with advanced metastatic cancer. Initial trials correlated doses of DB05448 with increased patient survival.

CI 1040 is an inhibitor of the mitogen-activated protein (MAP) kinase signal transduction pathway and has been shown to specifically inhibit MAP kinase kinase (MEK). CI 1040 was being developed by Parke-Davis (formerly a division of WarnerLambert, Now Pfizer) as an anticancer agent. It was the initial MEK inhibitor to undergo clinical evaluation based on promising preclinical activity. However, its development has been discontinued.

Tipifarnib is an oral farnesyltransferase (FTase) inhibitor which was developed by Janssen (J&J). Upon administration, tipifarnib inhibits FTase and thus suppresses the activity of downstream effectors. The drug reached phase III of clinical trials for such diseases as pancreatic cancer (terminated), colorectal cancer (terminated) and acute myeloid leukemia (in elderly patients).

CPI-1189 is a synthetic benzamide with antioxidant properties that blocks tumor necrosis factor-alpha (TNFalpha) effects in animal models. It has neuroprotective properties in model systems for HIV-associated neurotoxicity and thus is a candidate for neuroprotective therapy in humans with HIV-associated CNS disease. CPI-1189 was at the phase II stage of clinical development for the treatment of dementia associated with Parkinson's disease and AIDS Dementia Complex, however, development has been discontinued.

Pimonidazole (developed as RO 038799) is a derivative of 2-nitroimidazole, which forms adducts (binds to thiol-containing proteins) only at low oxygen tension. Pimonidazole is a novel nontoxic hypoxia marker for the complementary study of tumor hypoxia and cell proliferation in different types of cancer. The drawback of pimonidazole as a hypoxic marker is that it detects only severe hypoxia.

Cevipabulin is a synthetic, water-soluble tubulin-binding agent with potential antineoplastic activity. Cevipabulin appears to bind at the vinca-binding site on tubulin but seems to act more similar to taxane-site binding agents in that it enhances tubulin polymerization and does not induce tubulin depolymerization. The disruption in microtubule dynamics may eventually inhibit cell division and reduce cellular growth.

Taltobulin, also known as HTI-286 and SPA-110, is a fully synthetic analog of the natural tripeptide hemiasterlin, inhibits tubulin polymerization and circumvents transport-based resistance to taxanes. Taltobulin was a potent inhibitor of proliferation (mean IC50 = 4 nm in 18 human tumor cell lines) and had substantially less interaction with multidrug resistance protein (P-glycoprotein) than currently used antimicrotubule agents, including paclitaxel, docetaxel, vinorelbine, or vinblastine. Taltobulin showed strong antitumor activity both in androgen-dependent and androgen- independent tumors and may be a promising agent in second- line treatment strategies for patients suffering from docetaxel- refractory prostate cancer.

A second generation of HDACs, synthetic benzamide-containing HDACs such as Tacedinaline (CI-994), have reached phase I and II clinical trials. It has been investigated for its applications to the treatment of cancers such as Breast cancer and Colorectal cancer. Tacedinaline has been in phase III clinical trials by Pfizer for the treatment of advanced non-small cell lung cancer and pancreatic cancer combined with gemcitabine. However, this research has been discontinued. Mechanism of Action: Angiogenesis inhibitors; Histone deacetylase inhibitors. Pharmacokinetics showed that CI-994 absorption and disposition were unaffected by carboplatin and paclitaxel coadministration.

Filanesib is a highly selective, targeted KSP inhibitor with a mechanism of action distinct from currently available myeloma therapies such as immunomodulatory drugs (IMiDs®) and proteasome inhibitors. Across multiple studies, filanesib has demonstrated activity in heavily pretreated multiple myeloma patients, with a consistent safety profile including no drug-induced peripheral neuropathy and limited non-hematologic toxicity. Adverse events are generally limited to transient, non-cumulative and predominantly asymptomatic myelosuppression (decreases in blood counts) when supportive measures are used. Alpha 1-acid glycoprotein (AAG), a plasma protein, is a potential patient selection marker for filanesib. AAG is undergoing further investigation in clinical trials and could represent the first patient selection marker for a myeloma therapy. Filanesib is in Phase II for Multiple myeloma treatment.

Rabusertib is a Chk1 kinase inhibitor which was developed by ICOS for the treatment of cancer. The drug was tested in phase II of clinical trials for pancreatic cancer and non small cell lung carcinoma, but its development was discontinued. Now the drug is undergoing phase I trial in Japanese patients with solid tumors.