Swainsonine is an indolizidine alkaloid found in Australian Swainsona canescens, North American plants of the genera Astragalus and Oxytropis and also in the fungus Rhizoctonia leguminocola. It is competitive inhibitor of Golgi alpha-mannosidase II and lysosomal alpha-mannosidases. This compound has been reported to be a potent antiproliferative and immunomodulatory agent. However, no evidence of anti-tumor activity of swainsonine was seen in phase II clinical trial, in patients with locally advanced or metastatic renal cell carcinoma. Adverse events such as fatigue, nausea and diarrhea were common but generally mild. Swainsonine is locoweed toxin. Locoweed poisoning is seen throughout the world and annually costs the livestock industry millions of dollars. Swainsonine inhibits lysosomal alpha-mannosidase and Golgi mannosidase II. Poisoned animals are lethargic, anorexic, emaciated, and have neurologic signs that range from subtle apprehension to seizures.

Omtriptolide (previously known as PG490-88 or F60008), an immunosuppressant that has been shown to be the safe and potent antitumor agent and it has been approved entry into Phase I clinical trial for the treatment of prostate cancer in the USA. In addition, the drug is participating in phase I clinical trial for the treatment of myeloid leukemia. Experiments on animals have shown omtriptolide was highly effective in the prevention of murine graft-versus-host disease (GVHD). The immunosuppressive effect of the drug was mediated by inhibition of alloreactive T cell expansion through interleukin-2 production. However, this study was discontinued. Recently published article has shown omtriptolide possesses the potential as a prophylactic agent to prevent ischemia/reperfusion (I/R)-induced lung injury.

Patupilone is a compound isolated from the myxobacterium Sorangium cellulosum. Similar to paclitaxel, Patupilone induces microtubule polymerization and stabilizes microtubules against depolymerization conditions. In addition to promoting tubulin polymerization and stabilization of microtubules, this agent is cytotoxic for cells overexpressing P-glycoprotein, a characteristic that distinguishes it from the taxanes. Epothilone B may cause complete cell-cycle arrest. Patupilone failed a phase III trial for ovarian cancer in 2010.

Avagacestat (BMS-708163) is an oral gamma secretase inhibitor designed for selective inhibition of amyloid beta (Aβ) synthesis. Avagacestat was in development by Bristol-Myers Squibb for the treatment of Alzheimer's disease (AD). Avagacestat is a potent, selective, orally bioavailable γ-secretase inhibitor of Aβ40 and Aβ42 with IC50 of 0.3 nM and 0.27 nM, demonstrating a 193-fold selectivity against Notch. In November 2012, Bristol-Myers Squibb terminated clinical trials of the drug and announced its decision to end further development of avagacestat

Atopaxar, also known as E 5555 is a novel reversible protease-activated receptor-1 (PAR-1) thrombin receptor antagonist. The inhibition of thrombin-mediated platelet activation by means of protease-activated receptor-1 inhibitors represents an attractive therapeutic option for patients with atherothrombotic disease processes. In preclinical studies, atopaxar demonstrated inhibition of thrombin receptor-activating peptides (TRAP)- and thrombin-induced platelet aggregation. Atopaxar was being developed by Eisai for acute coronary syndromes (ACS) and coronary disorders, including atherothrombosis, unstable angina pectoris and myocardial infarction. Atopaxar was in phase II clinical development in the US, EU and Japan. However, development was discontinued in May 2012.

AstraZeneca was developing AZD-8055, an orally active mTORC1/mTORC2 inhibitor, for the treatment of advanced solid tumours. AZD-8055 is an ATP-competitive mTORC1/2 inhibitor that exhibits immunosuppressive and anticancer chemotherapeutic activities. AZD-8055 promotes antibody class switching in B cells at low doses and decreases B cell proliferation and differentiation at high doses. In vivo, this compound suppresses CC4 and CD8 T cell proliferation, increasing survival among MHC-mismatched heart transplant recipients. In vitro, AZD-8055 decreases viability of brain tumor cells; in vivo, it inhibits tumor growth. AZD-8055 had been in phase I trials by AstraZeneca for the treatment of malignant gliomas and solid tumours. However, this research has been discontinued.

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.

Tozadenant (SYN115) is an adenosine A2A receptor antagonist initially developed for treatment of Parkinson's disease but may also have utility in other CNS disorders. A2a receptors are expressed in high concentration in the striatum of the brain and play an important role in regulating motor function. Tozadenant blocks the effect of endogenous adenosine at the A2a receptors, resulting in the potentiation of the effect of dopamine at the D2 receptor and inhibition of the effect of glutamate at the mGluR5 receptor. This enables restoration of motor function in Parkinson’s disease. Tozadenant has the potential for use as mono-therapy or adjunctive therapy in combination with L-Dopa and dopamine agonists for the treatment of the motor and non-motor symptoms associated with Parkinson’s disease. may also have neuroprotective effects, which raises the possibility that it could slow the deterioration of dopamine producing cells and modify disease progression. As was reported in international, multicentre, phase 2b, randomised, double-blind, placebo-controlled, parallel-group, dose-finding clinical trial of tozadenant in levodopa-treated patients with Parkinson's disease who had motor fluctuations tozadenant at 120 or 180 mg twice daily was generally well tolerated and was effective at reducing off-time.

Raxatrigine also known as GSK1014802 and CNV-1014802, is a novel analgesic under development by Convergence Pharmaceuticals for the treatment of lumbosacral radiculopathy (sciatica) and trigeminal neuralgia (TGN). It is a novel state dependent small molecule sodium channel blocker that preferentially inhibits the Nav 1.7 ion channel, a therapeutic target implicated by genetics in human pain conditions. Raxatrigine is thought to penetrate the central nervous system and block Nav channels in a novel manner. CNV1014802 was granted orphan drug designation in 2013 by the US Food and Drug Administration (FDA) for the treatment of trigeminal neuralgia.

Intepirdine, also known as SB-742457, RVT-101, was originally developed by GlaxoSmithKline (GSK) as an antagonist of the serotonin receptor 6 (5-HT6). GSK sold the rights for further study of this drug to Axovant Sciences in 2014. Intepirdine is in phase 3 clinical trial for Alzheimer's and in a phase 2 trial for dementia with Lewy bodies.