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).

AT7519M or AT7519, a small molecule inhibitor of cyclin-dependent kinases 1, 2, 4, 5, and 9, participated in phase II clinical trials in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). As a result, in CLL, some patients had tumor reductions, but the objective response rate (ORR) was low. In MCL, activity was noted with ORR of 27%. In addition, AT7519M was studied in patients with previously treated multiple myeloma, to understand whether the drug alone or in combination with bortezomib were effective treatments. Recent experiments also have shown that AT7519 is a promising drug for the treatment of high-risk neuroblastoma patients with MYCN amplification. It is known, that MYCN-dependent neuroblastomas have low cure rates with current multimodal treatment.

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.

PF-03635659 is a potent, very long dissociative half-life (slow off-rate, >1440 min) muscarinic M3 antagonist. Spirometry data from healthy volunteers in phase I clinical studies illustrate that PF-03635659 provides efficacious 24 h bronchodilation from a single inhaled dose, thus confirming the suitability of PF-03635659 as a novel once-daily inhaled muscarinic M3 receptor antagonist for the treatment of chronic obstructive pulmonary disease (COPD). Safety (tachycardia) and toleration (dry mouth) data from the multidose phase I studies indicate an adverse event profile that is at least noninferior to tiotropium bromide. PF-03635659 had been in phase II clinical trial for the treatment of chronic obstructive pulmonary disease.

Pfizer developed fosdagrocorat (PF-04171327), a dissociated agonist of the glucocorticoid receptor for the treatment of rheumatoid arthritis. The drug successfully completed the phase II clinical trial; however, further study of the drug was discontinued.