Wednesday, August 12, 2015

Drugs in Clinical Pipeline: Givinostat

Givinostat [(6-((diethylamino)methyl)naphthalen-2-yl)methyl(4-(hydroxycarbamoyl) phenyl)carbamate] is an orally active, hydroxamic-containing histone deacetylase (HDAC) inhibitor, with broad anti-inflammatory, anti-angiogenic and anti-neoplastic properties.

Givinostat is pan-HDAC inhibitor showing potent inhibition of both Class I (IC50 HDAC 1, 2, 3 and 8 = 198, 325, 157 and 854 nM, respectively) and Class II HDACs (IC50 4, 5, 6, 7, 9, 10 and 11 = 1059, 532, 524, 541, 315, 340 and 292 nM, respectively). Furthermore, it reduces caspase-1 activity in human peripheral blood mononuclear cells (PBMC) and the secretion of IL-1β and other cytokines at 25-100 nM. At concentrations greater than 200 nM, Givinostat is toxic in vitro [1].

Givinostat has a dual anti-leukemic activity, since it induces apoptosis of both multiple myeloma (MM) and acute myelogenous leukemia (AML) cells and inhibits the production of IL-6 and VEGF by mesenchymal stromal cells (MSCs), two soluble factors crucial for leukemia growth and drug resistance. 

In 2010, Givinostat was granted orphan drug designation in the European Union for the treatment of systemic juvenile idiopathic arthritis and polycythaemia vera.

The activity of Givinostat is as follows:

IC50 (HDAC1 enzyme assay) = 198 nM
IC50 (HDAC2 enzyme assay) = 325 nM
IC50 (HDAC3 enzyme assay) = 157 nM
IC50 (HDAC8 enzyme assay) = 854 nM
IC50 (HDAC4 enzyme assay) = 1059 nM
IC50 (HDAC5 enzyme assay) = 532 nM
IC50 (HDAC7 enzyme assay) = 524 nM
IC50 (HDAC9 enzyme assay) = 541 nM
IC50 (HDAC6 enzyme assay) = 315 nM
IC50 (HDAC10 enzyme assay) = 340 nM
IC50 (HDAC11 enzyme assay) = 292 nM

Common Name: Givinostat
Synonyms: Gavinostat; ITF-2357; ITF 2357; ITF2357
IUPAC Name: (6-((diethylamino)methyl)naphthalen-2-yl)methyl (4-(hydroxycarbamoyl) phenyl)carbamate
CAS Number: 497833-27-9 
Mechanism of Action: HADC Inhibitor; pan-HADC Inhibitor; Histone Deacetylase Inhibitor
Indication: Various Cancers; Solid Tumors
Development Stage: Phase II
Company: Italfarmaco

DNA is tightly wrapped around nuclear histones and maintained in a state of deacetylation by histone deacetylases (HDACs), silencing gene expression. In humans, there are 18 HDACs divided into classes based on their dependence on zinc for enzyme activity. Class I (HDAC 1, 2,3, and 8) and Class II (HDAC 4, 5, 6, 7, 9, 10 and 11) are Zn-dependent enzymes, whereas class III (sirtuins 1-7) are NAD+ dependent. Although HDAC’s deacetylate the highly conserved N-terminal lysines on nuclear histones, HDACs also target cytosolic proteins such as transcription factors and proteins that regulate cell proliferation, migration and death (4). HDAC inhibitors hyperacetylate signal transducers and activators of transcription (STAT) and NFkβ, both of which are associated with decreased inflammation [1].

Low nonapoptotic concentrations of Givinostat reduce pro-inflammatory cytokine production in primary cells in vitro and exhibit anti-inflammatory effects in vivo. In lipopolysaccharide (LPS)-stimulated cultured human peripheral blood mononuclear cells (PBMCs), Givinostat reduced by 50% the release of tumor necrosis factor-alpha (TNFα) at 10 to 22 nM, the release of intracellular interleukin (IL)-1α at 12 nM, the secretion of IL-1β at 12.5 to 25 nM, and the production of interferon-gamma (IFNγ) at 25 nM. There was no reduction in IL-8 in these same cultures. Using the combination of IL-12 plus IL-18, IFNγ and IL-6 production was reduced by 50% at 12.5 to 25 nM, independent of decreased IL-1 or TNFα. There was no evidence of cell death in LPS-stimulated PBMCs at 100 nM Givinostat, using assays for DNA degradation, annexin V, and caspase-3/7. By Northern blotting of PBMCs, there was a 50% to 90% reduction in LPS-induced steady-state levels of TNFα and IFNγ mRNA but no effect on IL-1β or IL-8 levels. Real-time PCR confirmed the reduction in TNFα RNA by Givinostat. Oral administration of 1.0 to 10 mg/kg Givinostat to mice reduced LPS-induced serum TNFα and IFNγ by more than 50%. Anti-CD3-induced cytokines were not suppressed by Givinostat in PBMCs either in vitro or in the circulation in mice. In concanavalin-A-induced hepatitis, 1 or 5 mg/kg of oral Givinostat significantly reduced liver damage [2].

Givinostat inhibited production of growth and angiogenic factors by bone marrow stromal cells, in particular IL-6 and vascular endothelial growth factor (VEGF). Givinostat induced apoptosis in 8/9 MM and 6/7 AML cell lines, as well as 4/4 multiple myeloma (MM) and 18/20 acute myelogenous leukemia (AML) freshly isolated cases, with a mean IC50 of 0.2 uM. Givinostat activated the intrinsic apoptotic pathway, upregulated p21 and downmodulated Bcl-2 and Mcl-1. The drug induced hyperacetylation of histone H3, H4 and tubulin. When studied in more physiological conditions, Givinostat was still strongly cytotoxic for the interleukin-6 (IL-6)-dependent MM cell line CMA-03, or for AML samples maximally stimulated by co-culture on mesenchymal stromal cells (MSCs), but not for the MSCs themselves. Interestingly, Givinostat inhibited the production of IL-6, VEGF and interferon-italic gamma by MSCs by 80-95%. Finally, the drug significantly prolonged survival of severe combined immunodeficient mice inoculated with the AML-PS in vivo passaged cell line already at the 10 mg/kg oral dose [3].

1. Li, S.; et. al. Specific inhibition of histone deacetylase 8 reduces gene expression and production of proinflammatory cytokines in vitro and in vivo. Journal of Biological Chemistry 2014 DOI:
2. Leoni, F.; et. al. The histone deacetylase inhibitor ITF2357 reduces production of pro-inflammatory cytokines in vitro and systemic inflammation in vivo. Mol Med 2005, 11(1-12), 1-15.
3. Rambaldi, A.; et. al. The histone deacetylase inhibitor ITF2357 has anti-leukemic activity in vitro and in vivo and inhibits IL-6 and VEGF production by stromal cells. Leukemia 2007, 21, 1892-1900.