Valspodar (PSC-833) is a derivative of cyclosporin but devoid of the immunosuppressive and nephrotoxic properties seen in cyclosporin A. It exhibited high-affinity binding to Mdr1 P-glycoprotein (P-gp) and demonstrated multidrug resistance-reversing activity superior to cyclosporin A and verapamil both in vitro and in vivo. Preclinical and phase I/II clinical data have indicated that plasma levels of PSC-833 with multidrug resistance-reversing activities are achievable. Potent inhibition of intestinal, hepatobiliary and blood-brain barrier P-gp function has been demonstrated. The toxicity profiles of valspodar are acceptable and dose-limited by transient and reversible cerebellar ataxia. It has shown multidrug resistance-modulating activities towards acute myeloid leukemia, multiple myeloma and ovarian cancer in phase I/II clinical trials. However, the company discontinued development of valspodar in April 2001 following disappointing results reported from several multicentre phase III studies.

AT-9283 was being developed by Astex Pharmaceuticals as a treatment for cancer and myelofibrosis. AT-9283 is an inhibitor of mitosis (cell division) and is the second most progressed drug candidate in the Astex portfolio of novel molecularly targeted cancer drugs. All of Astex’s current products have been discovered internally using its proprietary drug discovery approach. AT9283 is a potent inhibitor of the Aurora A and B kinases and has been shown to arrest tumour growth in a range of tumour models. Aurora kinases play a key role in mitotic checkpoint control in cell division. Both Aurora A and B are over-expressed in many human tumours and are believed to be excellent targets for anti-cancer therapy.

GSK126, a potent, highly selective, S-adenosyl-methionine-competitive, small-molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and markedly inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma. EZH2 inactivation by GSK126 is also effective in killing MM cells and CSCs as a single agent or in combination with bortezomib. Clinical trial of GSK126 in patients with MM may be warranted. GSK126 is undergoing phase I trials for hypermethylation-related cancers. GSK126 is in phase I diffuse large B cell lymphoma and follicular lymphoma. GSK126 inhibits cell migration and angiogenesis in solid tumor cell lines through down-regulation of VEGF-A expression. Thus, it may be considered as a novel anticancer drug candidate for solid tumor.

CC-223 is an orally available inhibitor of the mammalian target of rapamycin (mTOR) with potential antineoplastic activity. mTOR kinase inhibitor CC-223 inhibits the activity of mTOR, which may result in the induction of tumor cell apoptosis and a decrease in tumor cell proliferation. CC-223 disrupted mitochondrial function, and induced mitochondrial permeability transition pore (mPTP) opening and reactive oxygen species (ROS) production. CC-223 is currently in phase II clinical trials for the treatment of Multiple myeloma; Non-Hodgkin's lymphoma; Solid tumours. The most common treatment-related adverse events were hyperglycemia, fatigue and rash.

CUDC-907 is a small molecule inhibitor of histone deacetylase and PI3 kinase developed by Curis. It is investigated in clinical trials for the treatment of relapsed or refractory lymphomas, thyroid cancer, multiple myeloma, breast cancer and other malignancies.

CPI-0610 is a small molecule inhibitor of the Bromodomain and Extra-Terminal (BET) family of proteins, with potential antineoplastic activity. Upon administration, the BET inhibitor CPI-0610 binds to the acetylated lysine recognition motifs on the bromodomain of BET proteins, thereby preventing the interaction between the BET proteins and acetylated histone peptides. This disrupts chromatin remodeling and gene expression. Prevention of the expression of certain growth-promoting genes may lead to an inhibition of tumor cell growth. CPI-0610 is currently being evaluated in three Phase 1 clinical trials in the U.S.

Idasanutlin (RG-7388) is a second-generation, orally bioavailable, selective p53-MDM2 antagonist. MDM2 is an important negative regulator of the p 53 tumor suppressor and is expressed at high levels in a large proportion of acute myeloid leukemia (AML). Blocking the MDM2-p53 interaction stabilizes p53 and activates p-53 mediated cell death and inhibition cell growth. Idasanutlin is under clinical trial in phase III for treatment AML and in combinations with others drugs in phase I/II for treatment of multiple myeloma.

CB-5083 is a novel first in class, potent orally bio-available p97 inhibitor that disrupts cellular protein homeostasis and demonstrates anti-tumor activity in solid and hematological models. CB-5083 causes rapid and sustained accumulation of poly-ubiquitin in tumor xenografts after a single administration. CB-5083 showed activity to inhibit tumor growth in multiple rodent models of human cancer. Furthermore, CB-5083 appears to exhibit greater potency over current proteasome inhibitors that further validate targeting p97 and protein homeostasis in the treatment of cancer. CB-5083 is a potent inhibitor of endoplasmic reticulum associated degradation and induces a lethal unfodled protein response. CB-5083 recently began Phase 1 testing in relapsed/refractory or refractory multiple myeloma, and advanced solid tumors.

Ipatasertib (LCL161) binds to inhibitors of apoptosis proteins (IAPs) with high affinity and initiates the destruction of cIAP1 and cIAP2, which further induces apoptosis via caspase activation. Ipatasertib is advancing in clinical development including five Phase 2 trials in patients with Breast cancer, Multiple myeloma, Myelofibrosis, Small cell lung cancer and Ovarian cancer. The most common LCL161-related adverse events were nausea and vomiting.

Icaritin is a monoprenylated favonol with 4′-methoxyl from Epimedium Genus. It has been documented to have osteoblastic and neuroprotective activities. It can reduce the incidence of steroid-associated oesteonecrosis in rabbit with inhibition of both intravascular thrombosis and extravascular lipid deposition for maintaining the integrity of intraosseous vasculature. Icaritin shows anti-infammatory activity and inhibitory activities against cancer cells. The phase III clinical trial is planned for the treatment of Hepatocellular carcinoma.