Gavinostat is an orally bioavailable hydroxymate inhibitor of histone deacetylase (HDAC) with potential anti-inflammatory, anti-angiogenic, and antineoplastic activities. Gavinostat inhibits class I and class II HDACs, resulting in an accumulation of highly acetylated histones, followed by the induction of chromatin remodeling and an altered pattern of gene expression. At low, nonapoptotic concentrations, this agent inhibits the production of pro-inflammatory cytokines such as tumor necrosis factor- (TNF-), interleukin-1 (IL-1), IL-6 and interferon-gamma. It is currently in phase 2 trials for Myeloproliferative disorders, Polycythaemia vera and Phase III for Duchenne muscular dystrophy announced. In clinical trials of givinostat as a salvage therapy for advanced Hodgkin's lymphoma, the most common adverse reactions were fatigue, mild diarrhea or abdominal pain, moderate thrombocytopenia, and mild leukopenia.

Dacinostat (also known as LAQ824), is a hydroxamate histone deacetylase inhibitor with potential anticancer activity. Dacinostat inhibits histone deacetylase enzymatic activities in vitro and transcriptionally activated the p21 promoter in reporter gene assays. Tumor cells treated with Dacinostat caused acetylation of HSP90 and degradation of its cargo oncoproteins. Flow cytometry studies revealed that both tumor cell lines and normal diploid fibroblasts arrested in the G2/M phase of the cell cycle after Dacinostat treatment. However, an increased sub-G1 population at 48 h (reminiscent of apoptotic cells) was only observed in the cancer cell lines treated with Dacinostat. Dacinostat exhibited antitumor effects in a xenograft animal models. In phase I trials, Dacinostat was well tolerated at doses that induced accumulation of histone acetylation, with higher doses inducing changes consistent with HSP90 inhibition. In another phase 1 in patients with advanced solid tumors, grade 3 or 4 toxicities were observed. Dacinostat had been in phase II clinical trials by Novartis for the treatment of solid tumors but further studies were discontinued.

R-306465 is a sulfonyl-derivative patented by Janssen Pharmaceutica N.V. as class I histone deacetylase inhibitor with broad-spectrum antitumoral activity against solid and hematological malignancies. R-306465 rapidly induced histone 3 (H3) acetylation and strongly upregulated expression of p21waf1,cip1, a downstream component of HDAC1 signaling, in A2780 ovarian carcinoma cells. R306465 showed class I HDAC isotype selectivity as evidenced by poor inhibition of HDAC6 (class IIb) confirmed by the absence of downregulation of Hsp90 chaperone c-RAF protein expression and tubulin acetylation. R306465 potently inhibited cell proliferation of all main solid tumor indications, including ovarian, lung, colon, breast and prostate cancer cell lines. Hematological cell lines, including acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphoblastic leukemia, chronic myeloid leukemia, lymphoma, and myeloma, were potently inhibited at a similar concentration range. R306465 induced apoptosis and inhibited angiogenesis in cell-based assays and had potent oral in vivo antitumoral activity in xenograft models.

Quisinostat is an orally bioavailable potent histone deacetylase inhibitor, specifically selected due to its sustained inhibition of HDAC1 in solid tumor tissues and prolonged period of half-elimination from tissues. Phase 2 clinical trials are ongoing in patients with platinum-resistant ovarian cancer and non-small cell lung cancer (NSCLC). Quisinostat is active in the treatment of patients with relapsed or refractory Sézary syndrome. The most common drug-related adverse events reported in this trial were: nausea, diarrhea, asthenia. Grade 3 adverse events were also reported: hypertension, lethargy and pruritus.

Trichostatin A (TSA) was originally isolated as an antifungal antibiotic along with its fermentation congeners trichostatin B ((TSA)3-Fe) and the D-glucopyranosides trichostatin C and D. TSA inhibits HDAC in the low nanomolar range and is an inducer of histone hyperacetylation, both in vitro and in vivo. It inhibits all class I and II deacetylases to a similar extent in both tumor and non-tumor cells, although HDAC4 is slightly resistant when compared with HDAC1 and HDAC6. Class III HDAC is not affected by TSA. It has been shown that TSA dosedependently inhibits growth and induces apoptosis in a plethora of carcinoma cell lines in vitro. Recently, it was also found that TSA inhibits angiogenesis, which is important for the growth and metastasis of solid tumors, both in vivo and in vitro. In HT-29 colon carcinoma cells, a single dose of TSA induced transient hyperacetylation of histone H4 resulting in the induction of p21WAF1/Cip1 and inhibition of cellular proliferation at both the G1 and G2 phases of the cell cycle. Growth inhibition was associated with decreased cyclin D1 mRNA and cdk6 protein levels and increased cyclin D3 protein and p21WAF1/Cip1 mRNA levels. Cyclin D1 protein, cyclin D3 mRNA, cdk2 and cdk4 remained unaffected. In addition, TSA induced apoptosis by upregulating the expression of the pro-apoptotic genes ID1, ID2 and ID3, whereas the expression of the anti-apoptotic genes BclxL and Hsp27 was decreased In vivo, TSA induces differentiation and shows chemotherapeutic activity against N-methylnitrosureainduced rat mammary cancer without toxic side effects. TSA may also have therapeutic potential for the treatment of a variety of genetic and infectious diseases since silenced, transduced genes are reactivated probably due to structural changes of the chromatin on integrated viral sequences.

Panobinostat is an oral deacetylace (DAC) inhibitor approved on February 23, 2015 by the FDA for the treatment of multiple myeloma. The approval was accelerated based on progression-free survival, therefore confirmatory trials by the sponsor to demonstrate clinical efficacy in multiple myeloma treatment are in progress of being conducted. Panobinostat is marketed by Novartis under the brand name Farydak. Panobinostat is a deacetylase (DAC) inhibitor. DACs, also known as histone DACs (HDAC), are responsible for regulating the acetylation of about 1750 proteins in the body; their functions are involved in many biological processes including DNA replication and repair, chromatin remodelling, transcription of genes, progression of the cell-cycle, protein degradation and cytoskeletal reorganization. In multiple myeloma, there is an overexpression of DAC proteins. Panobinostat inhibits class I (HDACs 1, 2, 3, 8), class II (HDACs 4, 5, 6, 7, 9, 10) and class IV (HDAC 11) proteins. Panobinostat's antitumor activity is believed to be attributed to epigenetic modulation of gene expression and inhibition of protein metabolism. Panobinostat also exhibits cytotoxic synergy with bortezomib, a proteasome inhibitor concurrently used in treatment of multiple myeloma.

Gavinostat is an orally bioavailable hydroxymate inhibitor of histone deacetylase (HDAC) with potential anti-inflammatory, anti-angiogenic, and antineoplastic activities. Gavinostat inhibits class I and class II HDACs, resulting in an accumulation of highly acetylated histones, followed by the induction of chromatin remodeling and an altered pattern of gene expression. At low, nonapoptotic concentrations, this agent inhibits the production of pro-inflammatory cytokines such as tumor necrosis factor- (TNF-), interleukin-1 (IL-1), IL-6 and interferon-gamma. It is currently in phase 2 trials for Myeloproliferative disorders, Polycythaemia vera and Phase III for Duchenne muscular dystrophy announced. In clinical trials of givinostat as a salvage therapy for advanced Hodgkin's lymphoma, the most common adverse reactions were fatigue, mild diarrhea or abdominal pain, moderate thrombocytopenia, and mild leukopenia.

Gavinostat is an orally bioavailable hydroxymate inhibitor of histone deacetylase (HDAC) with potential anti-inflammatory, anti-angiogenic, and antineoplastic activities. Gavinostat inhibits class I and class II HDACs, resulting in an accumulation of highly acetylated histones, followed by the induction of chromatin remodeling and an altered pattern of gene expression. At low, nonapoptotic concentrations, this agent inhibits the production of pro-inflammatory cytokines such as tumor necrosis factor- (TNF-), interleukin-1 (IL-1), IL-6 and interferon-gamma. It is currently in phase 2 trials for Myeloproliferative disorders, Polycythaemia vera and Phase III for Duchenne muscular dystrophy announced. In clinical trials of givinostat as a salvage therapy for advanced Hodgkin's lymphoma, the most common adverse reactions were fatigue, mild diarrhea or abdominal pain, moderate thrombocytopenia, and mild leukopenia.

Quisinostat is an orally bioavailable potent histone deacetylase inhibitor, specifically selected due to its sustained inhibition of HDAC1 in solid tumor tissues and prolonged period of half-elimination from tissues. Phase 2 clinical trials are ongoing in patients with platinum-resistant ovarian cancer and non-small cell lung cancer (NSCLC). Quisinostat is active in the treatment of patients with relapsed or refractory Sézary syndrome. The most common drug-related adverse events reported in this trial were: nausea, diarrhea, asthenia. Grade 3 adverse events were also reported: hypertension, lethargy and pruritus.

Panobinostat is an oral deacetylace (DAC) inhibitor approved on February 23, 2015 by the FDA for the treatment of multiple myeloma. The approval was accelerated based on progression-free survival, therefore confirmatory trials by the sponsor to demonstrate clinical efficacy in multiple myeloma treatment are in progress of being conducted. Panobinostat is marketed by Novartis under the brand name Farydak. Panobinostat is a deacetylase (DAC) inhibitor. DACs, also known as histone DACs (HDAC), are responsible for regulating the acetylation of about 1750 proteins in the body; their functions are involved in many biological processes including DNA replication and repair, chromatin remodelling, transcription of genes, progression of the cell-cycle, protein degradation and cytoskeletal reorganization. In multiple myeloma, there is an overexpression of DAC proteins. Panobinostat inhibits class I (HDACs 1, 2, 3, 8), class II (HDACs 4, 5, 6, 7, 9, 10) and class IV (HDAC 11) proteins. Panobinostat's antitumor activity is believed to be attributed to epigenetic modulation of gene expression and inhibition of protein metabolism. Panobinostat also exhibits cytotoxic synergy with bortezomib, a proteasome inhibitor concurrently used in treatment of multiple myeloma.