Antihistamine-resistant chronic spontaneous urticaria remains undertreated: 2-year data from the AWARE study.

BACKGROUND: Real-world evidence describing the benefits of recommended therapies and their impact on the quality of life (QoL) of chronic urticaria (CU) patients is limited. OBJECTIVE: To investigate disease burden, current treatment schedule, and the use of clinical resources by patients with H1 -antihistamine-refractory CU in Europe. METHODS: AWARE (A World-wide Antihistamine-Refractory chronic urticaria patient Evaluation) is a global, prospective, non-interventional study in the real-world setting, sponsored by the manufacturer of omalizumab. Disease characteristics, pharmacological treatments, and health-related QoL of patients (N = 2727) ≥18 years of age diagnosed with H1 -antihistamine-refractory chronic spontaneous urticaria (without inducible urticaria) for >2 months are reported here. RESULTS: Of the 2727 patients included, 1232 (45.2%) and 1278 (46.9%) were successfully followed up for any assessment and for the key outcome, the urticaria control test (UCT) score, respectively, and patients with complete remission (14.1%) were excluded from analyses.The proportion of patients with uncontrolled CSU (UCT score <12) dropped from 78% (n/N = 1641/2104) at baseline to 28.7% (n/N = 269/936) after two years of participation in the AWARE study. In addition, the proportion of patients with no impact of CSU on their QoL (assessed by the Dermatological Life Quality Index) increased to 57% (n/N = 664/1164) from 18.7% (n/N = 491/2621) at baseline. Emergency room visits (2.4% [n/N = 7/296] vs 33.5% [n/N = 779/2322]) and hospital stays (1.7% [n/N = 5/296] vs 24.2% [n/N = 561/2322]) reduced at Month 24 vs baseline. Overall, 23.2% (n/N = 26/112) patients on non-sedating H1 -antihistamines (nsAH) and 41.9% (n/N = 44/105) patients on up-dosed nsAH had uncontrolled CSU (UCT <12) at Month 24. In omalizumab-treated patients, 27.1% (n/N = 78/288) had uncontrolled CSU at Month 24. CONCLUSION: These data confirm improvements for most patients with CSU over a 2-year follow-up period. Further studies are needed to understand the differences between guideline recommendations and reported management.

Antihistamine-resistant chronic spontaneous urticaria: 1-year data from the AWARE study.

BACKGROUND: Previous reports indicate that patients with chronic spontaneous urticaria (CSU) are undertreated and that physicians show poor adherence to guideline recommendations. Awareness of CSU has improved in recent years, but it remains unclear if this has improved the management of these patients in clinical practice. OBJECTIVE: To describe disease burden, quality of life (QoL), and treatment patterns of patients with H1 -antihistamine-refractory CSU in Germany. METHOD: A World-wide Antihistamine-Refractory chronic urticaria (CU) patient Evaluation (AWARE) is a global prospective, non-interventional study of CU in the real-world setting, supported by the manufacturer of omalizumab. Patients (18-75 years) were included who had H1 -antihistamine-refractory CSU for ≥2 months. Disease characteristics, pharmacological treatments, and QoL (dermatology life quality index [DLQI], CU-QoL questionnaire, and angioedema QoL questionnaire) are reported for patients enrolled in Germany. RESULTS: After 1 year in AWARE, CSU remained uncontrolled (urticaria control test [UCT] score <12) in 432 of 1032 (42.2%) patients. QoL impairment remained high after 1 year, with 28.2% of patients reporting that CSU had a moderate/very large/extremely large effect on the DLQI. Most patients did not receive guideline-recommended treatments at the end of the 1-year observation period. Changes in treatments were most evident at the first patient visit, with an increase in patients receiving omalizumab vs prior therapy from 8.5% to 21.4%, and a decrease in those receiving no treatment from 29.9% to 12.8%. These changes were associated with reduced hives, angioedema, UCT scores, and QoL scores at Month 3, but only modest improvements thereafter. Of 528 patients with uncontrolled CSU and who were eligible for treatment escalation, only 3% received up-dosing of H1 -antihistamines and only 5% were initiated on omalizumab during 1 year of treatment. CONCLUSIONS & CLINICAL RELEVANCE: This study highlights a significant discrepancy between recommendations for managing CSU in international guidelines, and in real-world clinical practice in Germany.

Dual EZH2 and EHMT2 histone methyltransferase inhibition increases biological efficacy in breast cancer cells.

BACKGROUND: Many cancers show aberrant silencing of gene expression and overexpression of histone methyltransferases. The histone methyltransferases (HKMT) EZH2 and EHMT2 maintain the repressive chromatin histone methylation marks H3K27me and H3K9me, respectively, which are associated with transcriptional silencing. Although selective HKMT inhibitors reduce levels of individual repressive marks, removal of H3K27me3 by specific EZH2 inhibitors, for instance, may not be sufficient for inducing the expression of genes with multiple repressive marks. RESULTS: We report that gene expression and inhibition of triple negative breast cancer cell growth (MDA-MB-231) are markedly increased when targeting both EZH2 and EHMT2, either by siRNA knockdown or pharmacological inhibition, rather than either enzyme independently. Indeed, expression of certain genes is only induced upon dual inhibition. We sought to identify compounds which showed evidence of dual EZH2 and EHMT2 inhibition. Using a cell-based assay, based on the substrate competitive EHMT2 inhibitor BIX01294, we have identified proof-of-concept compounds that induce re-expression of a subset of genes consistent with dual HKMT inhibition. Chromatin immunoprecipitation verified a decrease in silencing marks and an increase in permissive marks at the promoter and transcription start site of re-expressed genes, while Western analysis showed reduction in global levels of H3K27me3 and H3K9me3. The compounds inhibit growth in a panel of breast cancer and lymphoma cell lines with low to sub-micromolar IC50s. Biochemically, the compounds are substrate competitive inhibitors against both EZH2 and EHMT1/2. CONCLUSIONS: We have demonstrated that dual inhibition of EZH2 and EHMT2 is more effective at eliciting biological responses of gene transcription and cancer cell growth inhibition compared to inhibition of single HKMTs, and we report the first dual EZH2-EHMT1/2 substrate competitive inhibitors that are functional in cells.

Heterochromatinization induced by GAA-repeat hyperexpansion in Friedreich's ataxia can be reduced upon HDAC inhibition by vitamin B3.

Large intronic expansions of the triplet-repeat sequence (GAA.TTC) cause transcriptional repression of the Frataxin gene (FXN) leading to Friedreich's ataxia (FRDA). We previously found that GAA-triplet expansions stimulate heterochromatinization in vivo in transgenic mice. We report here using chromosome conformation capture (3C) coupled with high-throughput sequencing that the GAA-repeat expansion in FRDA cells stimulates a higher-order structure as a fragment containing the GAA-repeat expansion showed an increased interaction frequency with genomic regions along the FXN locus. This is consistent with a more compacted chromatin and coincided with an increase in both constitutive H3K9me3 and facultative H3K27me3 heterochromatic marks in FRDA. Consistent with this, DNase I accessibility in regions flanking the GAA repeats in patients was decreased compared with healthy controls. Strikingly, this effect could be antagonized with the class III histone deactylase (HDAC) inhibitor vitamin B3 (nicotinamide) which activated the silenced FXN gene in several FRDA models. Examination of the FXN locus revealed a reduction of H3K9me3 and H3K27me3, an increased accessibility to DNase I and an induction of euchromatic H3 and H4 histone acetylations upon nicotinamide treatment. In addition, transcriptomic analysis of nicotinamide treated and untreated FRDA primary lymphocytes revealed that the expression of 67% of genes known to be dysregulated in FRDA was ameliorated by the treatment. These findings show that nictotinamide can up-regulate the FXN gene and reveal a potential mechanism of action for nicotinamide in reactivating the epigenetically silenced FXN gene and therefore support the further assessment of HDAC inhibitors (HDACi's) in FRDA and diseases caused by a similar mechanism.

On the determination of the stereochemistry of semisynthetic natural product analogues using chiroptical spectroscopy: desulfurization of epidithiodioxopiperazine fungal metabolites.

Isolation and semisynthetic modification of the fungal metabolite chaetocin gave access to a desulfurized analogue of this natural product. Detailed chiroptical studies, comparing experimentally obtained optical rotation values, electronic circular dichroism spectra, and vibrational circular dichroism spectra to computationally simulated ones, reveal the desulfurization of chaetocin to unambiguously proceed with retention of configuration. Consideration of the plausible mechanisms for this process highlighted inconsistencies in the stereochemical assignment of related molecules in the literature. This in turn allowed the stereochemical reassignment of the natural product analogue dethiodehydrogliotoxin.

Prospects for epigenetic compounds in the treatment of autoimmune disease.

There is growing evidence for a role for epigenetic mechanisms in the development of autoimmune diseases. In most cases ofautoimmune disease the precise epigenetic mechanism involved remains to be resolved, however DNA hypomethylation accompanied by hypoacetylation ofhistone H3/H4 is commonly observed. Due to the reversible nature of epigenetic marks their maintenance enzymes such as DNA methyltransferases (DNMTs), histone deacetylases (HDACs) and histone lysine methyltransferases (HKMT) are attractive drug targets. Small molecule inhibitors of histone modification and DNA methylation maintenance are increasingly becoming available and will be useful chemical biological tools to dissect epigenetic mechanisms in these diseases. However, although epigenetic therapies used in cancer treatment are a promising starting point for the exploration of autoimmune disease treatment, there is a requirement for more specific and less toxic agents for these chronic diseases or for use as chemopreventative agents.

Approaches to target the genome and its epigenome in cancer.

The term epigenetic landscape was coined by CH Waddington to describe how cell fates were established in development, visualized as valleys and ridges directing the irreversibility of cell type differentiation. It is now clear that normal differentiation control breaks down during tumor development and that all tumor types show aberrant regulation of the epigenetic code, including changes in DNA methylation, histone modification and microRNAs. This has led to much interest in the development of epigenetic cancer therapies to target this aberrant epigenetic regulation. Histone deacetylase and DNA methyltransferase inhibitors are now used in the treatment of certain hematological malignancies. However, their more general applicability to solid tumors may be limited by lack of specificity and delivery challenges. Approaches to overcome these limitations and how to develop more specific drugs are discussed. The use of RNAi in the context of genome regulation as well as the possibility to use polyamides and engineered zinc fingers to target master regulators in the future is examined. Ultimately, improved specificity of epigenetic therapies will require increased mapping of the aberrant epigenetic landscape in cancer and cancer-specific target validation using chemical epigenetic approaches.