Glutathione arsenoxide (GSAO) is a peptide trivalent arsenical that has potential anti-angiogenic capability, suggesting that it could be used for treatment in cancers where tumor metastasis relies on new blood vessel formation (angiogenesis). Endothelial cell proliferation drives new blood vessel formation. GSAO treatment causes a concentration-dependent increase in superoxide levels, ATP depletion, mitochondrial depolarization, and apoptosis in proliferating, but not endothelial cells. GSAO is able to block blood flow to solid tumors in mice, thereby inhibiting tumor growth in mice with no apparent toxicity at efficacious doses. Initial experiments have implicated GSAO in perturbing mitochondrial function. Other molecular effects of GSAO in human cells, for example on the phosphorylation of proteins, are still largely unknown. A phase I clinical trial has been terminated.

Rigosertib sodium (ON 01910.Na) is a small molecule inhibitor of critical pathways important in the growth and survival of cancer cells, being developed by Onconova Therapeutics ("Onconova") for the treatment of hematologic malignancies and solid tumors. Rigosertib (ON-01910) is a non-ATP-competitive inhibitor of PLK1 with IC50 of 9 nM in a cell-free assay. It shows 30-fold greater selectivity against Plk2 and no activity to Plk3. Extensive Phase I and Phase II studies with rigosertib have been conducted at leading institutions in the U.S. and abroad in more than 450 patients with solid tumors and hematological cancers, including MDS and AML. MDS and AML are blood disorders widely recognized as difficult to manage, with limited therapeutic options available for patients, especially those with drug-resistant disease. The multi-site Phase III ONTIME trial in MDS patients is under a Special Protocol Assessment (SPA) from the U.S. FDA and is being supported by an award from the Therapeutics Acceleration Program (TAP) of the Leukemia and Lymphoma Society (LLS). FDA has granted Orphan Drug Designation for the use of rigosertib in MDS. The clinical program in solid tumors is also advancing with initiation of the Phase II/III combination ONTRAC trial (ON 01910.Na TRial in Patients with Advanced Pancreatic Cancer) and Phase II single agent trial in ovarian cancer. In Japan, SymBio is developing rigosertib for the treatment of refractory/relapsed HR-MDS (IV form) and first-line LR-MDS (oral form).

Rebastinib (DCC-20) is a TIE2 kinase inhibitor currently in Phase 1 clinical development to treat breast cancer and Chronic Myeloid Leukemia. Rebastinib potently inhibited TIE2 kinase in cellular assays and blocked primary tumor growth by 75% as a single agent and by 90% in combination with the standard chemotherapeutic agent paclitaxel. Furthermore, rebastinib therapy significantly reduced the presence of tumor-promoting macrophages in tumor biopsies by 80%. This blockade of tumor macrophages correlated with inhibition of breast cancer lung metastases.

Miransertib (ARQ 092) is a selective, pan-AKT (protein kinase B) inhibitor that potently inhibits AKT1, 2 and 3 isoforms. Miransertib binds inactive AKT, preventing membrane localization and subsequent AKT activation, and binds active AKT, resulting in direct inhibition. Miransertib participates in Phase 1/2 of clinical trials to treat patients at least 2 years of age with PIK3CA-related Overgrowth Spectrum (PROS) and Proteus syndrome (PS). In addition, the drug is involved in the phase I trial in patients with lymphoma, endometrial cancer, and AKT1 E17K mutations. Recently was shown that miransertib could be an excellent lead compound for the development of new oral drug therapy for visceral and cutaneous leishmaniasis.

SNX-5422 (also known as PF-04929113) is a synthetic, novel, small molecule Hsp90 inhibitor with potential antineoplastic activity. Hsp90 is a molecular chaperone that plays a key role in the conformational maturation of oncogenic signaling proteins, such as HER2/ERBB2, AKT, RAF1, BCR-ABL, and mutated p53, as well as many other molecules that are important in cell cycle regulation or immune responses. Inhibition of Hsp90 by SNX-2112 may result in the proteasome degradation of oncogenic client proteins, including HER2/ERBB2, and the inhibition of tumor cell proliferation. SNX-5422 is originally developed by Pfizer and Serenex, Inc., and the phase I clinical trials for it has been completed in the treatment of solid tumors. Although the mechanism of action remains to be fully elucidated, SNX-5422, which is a prodrug, is rapidly converted to SNX-2112 that accumulates in tumors relative to normal tissues.

Asapiprant, also known as S-555739, a selective Prostaglandin D2 receptor 1 antagonist, participated in phase III of clinical trials in Japan and in phase II of trials in the USA for patients with Allergic rhinitis.