DS-3032 (Milademetan) is an orally available, potent and selective inhibitor of the p53-MDM2 (murine double minute 2) interaction. Milademetan binds to, and prevents the binding of MDM2 protein to the transcriptional activation domain of the tumor suppressor protein p53. Milademetan is 10-fold more potent than the first-generation inhibitor nutlin-3a. By preventing this MDM2-p53 interaction, the proteasome-mediated enzymatic degradation of p53 is inhibited and the transcriptional activity of p53 is restored. This results in the restoration of p53 signaling and leads to the p53-mediated induction of tumor cell apoptosis. DS-3032 is currently being evaluated in three phase 1 clinical trials for solid and hematological malignancies, including acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), chronic myeloid leukemia (CML) in blast phase, lymphoma and myelodysplastic syndrome (MDS).

GLPG0187 is a compound that belongs to the class of organic compounds known as naphthyridines, and has been studied as a potential drug in the treatment of solid tumors. GLPG0187 is a broad spectrum integrin receptor antagonist that inhibits αvβ1 integrin. In vitro, this compound was found to diminish the size of the aldehyde dehydrogenase high subpopulation of prostate cancer cells dose-dependently. It also significantly reduced tumor cell migration and cell proliferation. In vivo, it reduced metastatic tumor growth, and inhibited the progression of bone metastases as well as the formation of new bone metastases. Phase I studies have been completed to study safety and drug tolerance of GLPG0187. The drug was well tolerated, but continuous infusion of GLPG0187 did not show signs of monotherapy efficacy.

13-deoxyadriamycin hydrochloride (13-Deoxydoxorubicin hydrochloride, GPX-100) is an anthracycline similar to doxorubicin. GPX-100 is unique among anthracyclines because it is not converted to doxorubicinol during metabolism in the body. This metabolite has been shown to be a major cause of damage to the heart (cardiotoxicity) in laboratory studies. GPX-100 belongs to the class of reactive oxygen species stimulants; RNA synthesis inhibitors and Type II DNA topoisomerase inhibitors. It was in phase II clinical trial for the treatment of cancer.

Nitroarginine (LNNA), an analog of L-arginine, is a competitive inhibitor of nitric oxide synthase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. The Kd value (k(off)/k(on)) of bovine brain cNOS for LNNA was 15 nM. In contrast to the potent and slow onset of LNNA inhibition of brain cNOS, LNNA inhibition of inducible mouse macrophage NOS (iNOS) was weaker (Ki = 4.4 uM) and rapidly reversible. Thus, LNNA was a 300-fold more potent inhibitor of bovine brain cNOS than mouse macrophage iNOS. By inhibiting nitric oxide synthase LNNA causes the selective reduction of blood flow to tumor cells. Despite the potential of LNNA to function as an adjuvant in cancer therapies, its poor solubility and stability have hindered the development of an injectable formulation of LNNA that is suitable for human administration.