Buthionine sulfoximine (BSO) is a selective inhibitor of γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting enzyme in glutathione (GSH) synthesis. In cancer cells, glutathione depletion significantly increased cytotoxicity via oxidative stress. In addition, in neuroblastoma cells susceptible to Buthionine sulfoximine treatment, DNA damage and cell apoptosis occurred via ROS production. Buthionine sulfoximine plus melphalan was effective in treatment for patients with recurrent/refractory neuroblastoma. Buthionine sulfoximine may also be used to increase the sensitivity of parasites to oxidative antiparasitic drugs. Buthionine sulfoximine has been shown to increase the efficacy of nifurtimox against T. cruzi and has also been shown to be an effective modulator of GSH-mediated chemoresistance by increasing the in vitro cytotoxicity of alkylating agents and radiation. Buthionine sulfoximine has been tested in animal studies and in human phase I trials for adults with solid tumors, with documented clinical responses in patients with melanoma, ovarian carcinoma and small cell carcinoma of the lung treated with the combination of Buthionine sulfoximine and melphalan.

BVD-523 potently and selectively inhibits ERK1 and ERK2 kinases in a reversible, ATP-competitive fashion. Consistent with its mechanism of action, BVD-523 inhibits signal transduction, cell proliferation, and cell survival, most potently in cell lines bearing mutations that activate MAPK pathway signaling. Similarly, single-agent BVD-523 inhibits tumor growth in vivo in BRAF-mutant melanoma and colorectal xenografts as well as in KRAS-mutant colorectal and pancreatic models. BioMed Valley Discoveries is developing ulixertinib, a potent and selective small molecule inhibitor of ERK 1 and 2 kinases, as an oral treatment for cancers harbouring mutations in the MAPK signaling pathway. Phase I/II development of the drug for advanced cancers including, acute myeloid leukaemia and myelodysplastic syndromes is underway in the US. A phase I trial is underway in the US for pancreatic cancer.

Peldesine (also known as BCX-34) was developed as a purine nucleoside phosphorylase (PNP) inhibitor. It is known PNP inhibitors may be useful for treating a variety of T-cell related autoimmune diseases including psoriasis, rheumatoid arthritis, and Crohn s disease and T-cell cancers. Peldesine has undergone phase I trials for the treatment of human Immunodeficiency virus (HIV) infections. In addition, this drug participated in phase III clinical trial as a topical therapy for cutaneous T-cell lymphoma. This drug was also studied as a potential therapy for psoriasis, multiple sclerosis; rheumatoid arthritis; transplant rejection. However, all these indications were discontinued because of the lack of significant effects over placebo.

CEP-37440 is a potent ATP-competitive, highly kinase selective, and orally active inhibitor of FAK1 and anaplastic lymphoma kinase (ALK). In addition to a favorable metabolic stability and pharmacokinetic profile preclinically, CEP-37440 is also a brain penetrant. CEP-37440 was able to inhibit the proliferation of certain IBC cells by decreasing the levels of phospho-FAK1 (Tyr 397); none of the cells expressed ALK. Studies using IBC xenograft models showed that CEP-37440 also effectively reduces the growth of the primary tumor xenografts and inhibits the development of brain metastases in mice.

Fantofarone (SR 33557) is a non-dihydropyridine calcium antagonist with a novel site of action in the L-type Ca2+ channel. Fantofarone is capable of significantly modifying the cardiovascular function without increasing heart rate. Fantofarone was being developed for the treatment of angina pectoris, arrhythmias and hypertension.

Zamicastat (also known as BIA 5-1058) is a dopamine β-hydroxylase (DβH) inhibitor that decreases noradrenaline and increases dopamine levels in peripheral sympathetically innervated tissues. It is known that the use of DβH inhibitors is a promising approach to treat hypertension, heart failure and cardiovascular diseases where a reduction in the sympathetic tone has beneficial effects. Zamicastat participated in phase II clinical trials in pulmonary arterial hypertension as adjuvant therapy in Austria. In addition, the drug successfully completed phase I in patients with hypertension and chronic heart failure.

Naquotinib (ASP8273) is an orally available, irreversible, mutant-selective, epidermal growth factor receptor (EGFR) inhibitor, with potential antineoplastic activity. Naquotinib was found by mass spectrometry to covalently bind to a mutant EGFR (L858R/ T790M) via cysteine residue 797 in the kinase domain of EGFR with long-lasting inhibition of EGFR phosphorylation for 24 h. In the NSCLC cell lines harboring the above EGFR mutations, Naquotinib had IC50 values of 8-33 nM toward EGFR mutants, more potently than that of WT EGFR (IC50 value of 230 nM). In mouse xenograft models, Naquotinib induced complete regression of the tumors after 14 days of treatment. ASP8273 even showed activity in mutant EGFR cell line which is resistant to other EGFR TKIs. Naquotinib is in phase III clinical trials for the oral treatment of EGFR mutated non-small cell lung cancer (NSCLC).

CP-609754 is a farnesyltransferase inhibitor, originally developed by OSI Pharmaceuticals and Pfizer for the treatment of patients with Ras-positive cancer. CP-609754 demonstrated in vivo antitumor activity against 3T3 H-ras (61L) tumors. The compound was investigated in phase 1 clinical trials in patients with advanced malignant tumors, and dose 640 mg twice per day was established as a recommended for phase 2 clinical trials. The clinical trials, however, were not conducted because of disappointing results of other farnesyl transferase inhibitors, and in 2006 the drug was licensed to Link Medicine for the treatment of neurodegenerative diseases. Under the codename LNK-754, the compound was investigated in mouse models of Parkinson's disease and two models of Alzheimer's disease, where positive results were demonstrated. Two phase 1 clinical trials of LNK-754 in healthy volunteers and patients with mild Alzheimer's disease were conducted in 2009, but no further development of the drug was reported.

Roniciclib (BAY1000394) is a pan-cyclin-dependent kinase inhibitor that has been developed for treatment in small cell lung carcinoma and solid tumors. Roniciclib targets certain key proteins that are essential for the survival of cancer cells, resulting in decreased tumor growth. Phase I studies to evaluate the safety, tolerability and pharmacokinetics of roniciclib have been completed successfully. In phase II studies, roniciclib was found to be well tolerated and showed promising efficacy when combined with chemotherapy in small cell lung carcinoma patients. However, due to an observed safety signal (treatment-emergent adverse events) in one phase II study, other clinical trials have been discontinued and further development of roniciclib was terminated.