Abexinostat (PCI-24781) is a novel, second-generation phenyl hydroxamic acid–based, orally bioavailable HDAC inhibitor that has previously been shown to have activity in vitro and in vivo against a broad array of cancers, including hematopoietic malignancies and bone and soft-tissue sarcomas. Abexinostat is a pan-HDAC inhibitor mostly targeting HDAC1 with Ki of 7 nM, modest potent to HDACs 2, 3, 6, and 10 and greater than 40-fold selectivity against HDAC8. Abexinostat exhibits potent antitumor activity against a variety of tumor cell lines with GI50 ranging from 0.15 uM to 3.09 uM. PCI-24781 also has an antiproliferative effect on HUVEC endothelial cells with GI50 of 0.43 uM. Abexinostat treatment causes dose-dependent accumulation of both acetylated histones and acetylated tubulin in HCT116 or DLD-1 cells, induces expression of p21, and leads to PARP cleavage and accumulation of the γH2AX. It has also shown good tolerability and activity in Phase I and II clinical trials against lymphoma, as well as against solid tumors in Phase-I trials. Additionally, it acts as a potent radiosensitizing agent and is synergistic with cytotoxic chemotherapy, such as doxorubicin in preclinical models.

Adaprolol is a beta-adrenergic antagonist that is being developed as a topical agent to treat glaucoma. Adaprolol demonstrated a safer cardiovascular profile, especially in the population over 70 years old. It was in Phase II clinical trials for the treatment of glaucoma. This research has been discontinued.

NMED-160 (also known as MK-6721, NP-118809, Z-160) is a potent N-type calcium channel blockers, which has good selectivity over L-type calcium channels. Neuromed Pharmaceuticals developed this compound for the treatment of the chronic pain. However, that study was discontinued in 2007 in spite of absence of adverse events, but because drug did not demonstrate the ideal, pharmaceutical characteristics considered necessary to advance the compound further in development. Then Zalicus, Inc. was developing that drug for the treatment of chronic neuropathic pain associated with lumbosacral radiculopathy and post-herpetic neuralgia and drug was in the phase II clinical trial. Nevertheless, based on the result from trials, where Z160 did not meet the primary endpoint, Zalicus was also discontinuing the Z160 program.

Elinogrel, previously known as PRT060128 or PRT128, is a direct-acting, reversible P2Y12 inhibitor for both intravenous and oral administration. Elinogrel has been tested in 2 phase II studies for the treatment of acute coronary syndrome, myocardial infarction and prevention of secondary thrombotic events. Elinogrel therapy was associated with an increased incidence of dyspnea and incidence of elevated liver transaminases. The development of the drug was terminated in January 2012 by Novartis.

Radezolid (RX-1741) is a novel oxazolidinone antibiotic agent and is the first biaryloxazolidinone in clinical development. It is being developed by Rib-X Pharmaceuticals, Inc. for the treatment of serious multi-drug–resistant infections. Radezolid has completed two phase-II clinical trialsfor the treatment of community-acquired pneumonia; uncomplicated skin and skin structure infections. The mechanism of action for this drug seems to be an inhibition of 50S ribosomal subunit.

Declopramide is an apoptosis inducer. Also, it inhibits NFkappaB activation by inhibition of IkappaBbeta breakdown. In preclinical research, Declopramide demonstrated strong antitumor properties. It had been in phase II clinical trials for the treatment of colorectal cancer. However, this research has been discontinued.

Elarofiban is a novel nonpeptide glycoprotein IIb/IIIa (GPIIb/IIIa) antagonist. It inhibits thrombin-induced platelet aggregation in human gel-filtered platelets and platelet aggregation in human platelet-rich plasma (PRP) in response to collagen, arachidonic acid, ADP, and SFLLRN-NH(2). Elarofiban had adequate oral pharmacokinetics in dogs and excellent oral pharmacodynamics. Elarofiban has been in phase II clinical trials for the treatment of myocardial infarction and thrombosis. However, this research has been discontinued.

Sotrastaurin, an orally-active, first-in-class immunomodulator, is under development by Novartis for the treatment of uveal melanoma and diffuse-large B-cell lymphoma. Sotrastaurin is a low molecular mass synthetic compound that potently inhibits the PKC α, β and the θ isoforms resulting in selective NF-κB inactivation. Sotrastaurin is a potent and selective pan-PKC inhibitor, mostly for PKCθ with Ki of 0.22 nM in a cell-free assay. Inhibition of PKC beta in B-cells results in prevention of NF-kB-mediated signaling and down regulation of NF-kB target genes. This may eventually lead to an induction of G1 cell cycle arrest and tumor cell apoptosis in susceptible tumor cells. This agent may act synergistically with other chemotherapeutic agents. PKC, a family of serine/threonine protein kinases overexpressed in certain types of cancer cells, is involved in cell differentiation, mitogenesis, inflammation, and the activation and survival of lymphocytes. Sotrastaurin is currently in phase II trials by Novartis for the treatment of large B-cell lymphoma and uveal melanoma. Sotrastaurin was in Phase II of clinical development for the prevention of acute rejection after solid organ transplantation and psoriasis, but this reseach had being discontinued.

Tozasertib, originally developed as VX-680 by Vertex (Cambridge, MA) and later renamed MK-0457 by Merck (Whitehouse Station, NY), was the first aurora kinase inhibitor to be tested in clinical trials. The drug, a pyrimidine derivative, has affinity for all aurora family members at nanomolar concentrations with inhibitory constant values (Ki(app)) of 0.6, 18, and 4.6 nM for aurora A, aurora B, and aurora C, respectively. Preclinical studies confirmed that tozasertib inhibited both aurora A and aurora B kinase activity, and activity has been reported against prostate, thyroid, ovarian, and oral squamous cancer cell lines. Upon treatment with tozasertib, cells accumulate with a 4N DNA content due to a failure of cytokinesis. This ultimately leads to apoptosis, preferentially in cells with a compromised p53 function. Tozasertib is an anticancer chemotherapeutic pan-aurora kinase (AurK) inhibitor that also inhibits FMS-like tyrosine kinase 3 (FLT3) and Abl. Tozasertib is currently in clinical trials as a potential treatment for acute lymphoblastic leukemia (ALL). In cellular models of cancer, tozasertib activates caspase-3 and PARP and decreases expression of HDAC, increasing apoptosis and inhibiting cell growth. In other cellular models, tozasertib inhibits cell proliferation and metastasis by blocking downstream ERK signaling and downregulating cdc25c and cyclin B. This compound also decreases tumor growth in an in vivo model of prostate cancer.

Lanicemine is a low-trapping NMDA channel blocker, which was developed by Fisons Pharmaceuticals and later by AstraZeneca for the treatment of the major depressive disorder. The development was terminated in phase II as the drug did not meet the primary endpoint.