Randomized, double-blind, placebo-controlled study of safety and efficacy of miltefosine in antihistamine-resistant chronic spontaneous urticaria

Evidence Gaps in Clinical Trials of Pharmacologic Treatment for H1-Antihistamine-Refractory Chronic Spontaneous Urticaria: A Systematic Review and Future Perspectives

No data addressing issues concerning disparities in participant and trial characteristics and trial outcome reporting have been established in clinical trials for H1-antihistamine-refractory chronic spontaneous urticaria (CSU). To better harmonize and compare the different treatment interventions, we systematically evaluated the overall landscape of pharmacological treatments for H1-antihistamine-refractory CSU clinical trials published between 2000 and 2021. This systematic review included 23 randomized clinical trials involving 2480 participants from 22 countries. We found significant increases in the number of globally published and newly tested drugs, especially biologic drugs. Regarding relatively small trials, we found that people living with H1-antihistamine-refractory CSU who were identified as members of minority groups (non-white population), populations of regions other than North America/Europe, and populations of low- to lower/upper-middle-income countries are underrepresented. Most trials were designed to evaluate treatment efficacy and safety profiles; however, less than half of the included trials reported the patient’s perspective in terms of patient-reported outcomes. Disparities in outcome reporting, including clinimetric tools for assessing treatment response and outcome sets, were observed. To close the evidence gap in H1-antihistamine-refractory CSU trials, strategies for improving trial and participant enrollment and standardizing core outcome sets for trial reporting are needed.

Impact of Pharmacological Treatments for Chronic Spontaneous Urticaria with an Inadequate Response to H1-Antihistamines on Health-Related Quality of Life: A Systematic Review and Network Meta-Analysis

BACKGROUND

Recently, pharmacological treatment options for H1-antihistamine-refractory chronic spontaneous urticaria have increased dramatically; however, their effects on patient-reported outcomes, including health-related quality of life (HRQOL), remain unclear.

OBJECTIVE

To compare the impact of these treatments on HRQOL among H1-antihistamine-refractory patients with chronic spontaneous urticaria.

METHODS

We completed a comprehensive search of the available literature in the electronic databases, gray literature, and preprint reports up to April 19, 2021, with no language restrictions. The primary outcome for evaluation was a change in HRQOL from the baseline, and secondary outcomes included patient unacceptability and other patient-reported outcomes. We used a random-effects network meta-analysis and estimated differences in standardized mean differences (SMDs) and odds ratios with 95% CIs. Evidence-based synthesis was based on magnitudes of effect size, evidence certainty, ranking of treatment effects, and clinically meaningful improvement.

RESULTS

Twelve randomized controlled trials encompassing 1866 adolescent and adult patients were included. Our evidence synthesis analyses revealed that hydroxychloroquine (SMD, -1.00 [-1.61 to -0.39]), 72 mg ligelizumab (SMD, -0.66 [-0.96 to -0.35]), 240 mg ligelizumab (SMD, -0.67 [-0.98 to -0.37]), and 300 mg omalizumab (SMD, -0.53 [-0.67 to -0.39]) significantly improved HRQOL with a moderate beneficial effect. However, the use of hydroxychloroquine seems to be limited by a higher risk of patient unacceptability of treatment. Other secondary outcomes remain inconclusive based on the available evidence.

CONCLUSIONS

Both ligelizumab (72 or 240 mg) and 300 mg omalizumab appeared to be effective treatments for H1-antihistamine-refractory chronic spontaneous urticaria, because they were closely associated with improved HRQOL.

Evaluation of Pharmacologic Treatments for H1 Antihistamine-Refractory Chronic Spontaneous Urticaria: A Systematic Review and Network Meta-analysis

Importance

The comparative benefits and harms of all available treatments for H1 antihistamine-refractory chronic spontaneous urticaria (CSU) have not been established.

Objective

To evaluate different treatment effects of pharmacologic treatments among patients with H1 antihistamine-refractory CSU.

Data Sources

Searches were conducted of MEDLINE, Embase, PubMed, Cochrane Library, Web of Science, Scopus, and CINAHL from inception to April 19, 2021, with no language restrictions. Gray literature from Google Scholar, ongoing trial registers, and preprint reports was added to the searches of electronic databases.

Study Selection

Randomized clinical trials using validated measurement tools that investigated the benefits and harms of pharmacologic treatments among adolescent or adult patients with CSU who had an inadequate response to H1 antihistamines were screened for inclusion independently by 2 investigators.

Data Extraction and Synthesis

Two investigators independently extracted study data according to the predefined list of interests. A random-effects model was used to calculate the network estimates reported as standardized mean differences and odds ratios with corresponding 95% CIs.

Main Outcomes and Measures

The primary outcomes that reflect the patient's perspective included changes in urticaria symptoms from baseline and unacceptability of treatment (all-cause dropouts).

Results

Twenty-three randomized clinical trials with 2480 participants that compared 18 different interventions or dosages and placebo were included. The standardized mean differences for change in urticaria symptoms were -1.05 (95% CI, -1.37 to -0.73) for ligelizumab, 72 mg; -1.07 (95% CI, -1.39 to -0.75) for ligelizumab, 240 mg; -0.77 (95% CI, -0.91 to -0.63) for omalizumab, 300 mg; and -0.59 (95% CI, -1.10 to -0.08) for omalizumab, 600 mg. No significant differences in treatment unacceptability were observed. With respect to benefits and harms, the network estimates illustrated that the most efficacious treatments were achieved with ligelizumab, 72 or 240 mg (large beneficial effect) and omalizumab, 300 or 600 mg (moderate beneficial effect).

Conclusions and Relevance

The findings in this meta-analysis suggest that the biologic agents ligelizumab, 72 or 240 mg, and omalizumab, 300 or 600 mg, can be recommended as effective treatments for patients with CSU who have had an inadequate response to H1 antihistamines. Head-to-head trials with high methodologic quality and harmonized design and outcome definitions are needed to help inform subsequent international guidelines for the management of CSU.

Emerging Role of Phospholipase-Derived Cleavage Products in Regulating Eosinophil Activity: Focus on Lysophospholipids, Polyunsaturated Fatty Acids and Eicosanoids

Eosinophils are important effector cells involved in allergic inflammation. When stimulated, eosinophils release a variety of mediators initiating, propagating, and maintaining local inflammation. Both, the activity and concentration of secreted and cytosolic phospholipases (PLAs) are increased in allergic inflammation, promoting the cleavage of phospholipids and thus the production of reactive lipid mediators. Eosinophils express high levels of secreted phospholipase A2 compared to other leukocytes, indicating their direct involvement in the production of lipid mediators during allergic inflammation. On the other side, eosinophils have also been recognized as crucial mediators with regulatory and homeostatic roles in local immunity and repair. Thus, targeting the complex network of lipid mediators offer a unique opportunity to target the over-activation and 'pro-inflammatory' phenotype of eosinophils without compromising the survival and functions of tissue-resident and homeostatic eosinophils. Here we provide a comprehensive overview of the critical role of phospholipase-derived lipid mediators in modulating eosinophil activity in health and disease. We focus on lysophospholipids, polyunsaturated fatty acids, and eicosanoids with exciting new perspectives for future drug development.

The anti-parasitic drug miltefosine suppresses activation of human eosinophils and ameliorates allergic inflammation in mice

BACKGROUND AND PURPOSE

Miltefosine is an alkylphosphocholine drug with proven effectiveness against various types of parasites and cancer cells. Miltefosine is not only able to induce direct parasite killing but also modulates host immunity, for example by reducing the severity of allergies in patients. To date, there are no reports on the effect of miltefosine on eosinophils, central effector cells involved in allergic inflammation.

EXPERIMENTAL APPROACH

We tested the effect of miltefosine on the activation of human eosinophils and their effector responses in vitro and in mouse models of eosinophilic migration and ovalbumin-induced allergic lung inflammation.

KEY RESULTS

The addition of miltefosine suppressed several eosinophilic effector reactions such as CD11b up-regulation, degranulation, chemotaxis and downstream signalling. Miltefosine significantly reduced the infiltration of immune cells into the respiratory tract of mice in an allergic cell recruitment model. Finally, in a model of allergic inflammation, treatment with miltefosine resulted in an improvement of lung function parameters.

CONCLUSION AND IMPLICATIONS

Our observations suggest a strong modulatory activity of miltefosine in the regulation of eosinophilic inflammation in vitro and in vivo. Our data underline the potential efficacy of miltefosine in the treatment of allergic diseases and other eosinophil-associated disorders and may raise important questions regarding the immunomodulatory effect of miltefosine in patients treated for leishmania infections.

Miltefosine treatment reduces visceral hypersensitivity in a rat model for irritable bowel syndrome via multiple mechanisms

Irritable bowel syndrome (IBS) is a heterogenic, functional gastrointestinal disorder of the gut-brain axis characterized by altered bowel habit and abdominal pain. Preclinical and clinical results suggested that, in part of these patients, pain may result from fungal induced release of mast cell derived histamine, subsequent activation of sensory afferent expressed histamine-1 receptors and related sensitization of the nociceptive transient reporter potential channel V1 (TRPV1)-ion channel. TRPV1 gating properties are regulated in lipid rafts. Miltefosine, an approved drug for the treatment of visceral Leishmaniasis, has fungicidal effects and is a known lipid raft modulator. We anticipated that miltefosine may act on different mechanistic levels of fungal-induced abdominal pain and may be repurposed to IBS. In the IBS-like rat model of maternal separation we assessed the visceromotor response to colonic distension as indirect readout for abdominal pain. Miltefosine reversed post-stress hypersensitivity to distension (i.e. visceral hypersensitivity) and this was associated with differences in the fungal microbiome (i.e. mycobiome). In vitro investigations confirmed fungicidal effects of miltefosine. In addition, miltefosine reduced the effect of TRPV1 activation in TRPV1-transfected cells and prevented TRPV1-dependent visceral hypersensitivity induced by intracolonic-capsaicin in rat. Miltefosine may be an attractive drug to treat abdominal pain in IBS.

Systematic Review of Host-Mediated Activity of Miltefosine in Leishmaniasis through Immunomodulation

Host immune responses are pivotal for the successful treatment of the leishmaniases, a spectrum of infections caused by Leishmania parasites. Previous studies speculated that augmenting cytokines associated with a type 1 T-helper cell (Th1) response is necessary to combat severe forms of leishmaniasis, and it has been hypothesized that the antileishmanial drug miltefosine is capable of immunomodulation and induction of Th1 cytokines.

Host immune responses are pivotal for the successful treatment of the leishmaniases, a spectrum of infections caused by Leishmania parasites. Previous studies speculated that augmenting cytokines associated with a type 1 T-helper cell (Th1) response is necessary to combat severe forms of leishmaniasis, and it has been hypothesized that the antileishmanial drug miltefosine is capable of immunomodulation and induction of Th1 cytokines. A better understanding of the immunomodulatory effects of miltefosine is central to providing a rationale regarding synergistic mechanisms of activity to combine miltefosine optimally with other conventional and future antileishmanials that are currently under development. Therefore, a systematic literature search was performed to evaluate to what extent and how miltefosine influences the host Th1 response. Miltefosine’s effects observed in both a preclinical and a clinical context associated with immunomodulation in the treatment of leishmaniasis are evaluated in this review. A total of 27 studies were included in the analysis. Based on the current evidence, miltefosine is not only capable of inducing direct parasite killing but also of modulating the host immunity. Our findings suggest that miltefosine-induced activation of Th1 cytokines, particularly represented by increased gamma interferon (IFN-γ) and interleukin 12 (IL-12), is essential to prevail over the Leishmania-driven Th2 response. Differences in miltefosine-induced host-mediated effects between in vitro, ex vivo, animal model, and human studies are further discussed. All things considered, an effective treatment with miltefosine is acquired by enhanced functional Th1 cytokine responses and may further be enhanced in combination with immunostimulatory agents.

Mast Cell Activation and Microtubule Organization Are Modulated by Miltefosine Through Protein Kinase C Inhibition

Mast cells play an effector role in innate immunity, allergy, and inflammation. Antigen-mediated activation of mast cells initiates signaling events leading to Ca²⁺ response and the release of inflammatory and allergic mediators from granules. Diseases associated with deregulated mast cell functions are hard to treat and there is an increasing demand for new therapeutic strategies. Miltefosine (hexadecylphosphocholine) is a new candidate for treatment of mast cell-driven diseases as it inhibits activation of mast cells. It has been proposed that miltefosine acts as a lipid raft modulator through its interference with the structural organization of surface receptors in the cell membrane. However, molecular mechanisms of its action are not fully understood. Here, we report that in antigen-activated bone marrow-derived mast cells (BMMCs), miltefosine inhibits degranulation, reorganization of microtubules, as well as antigen-induced chemotaxis. While aggregation and tyrosine phosphorylation of IgE receptors were suppressed in activated cells pre-treated with miltefosine, overall tyrosine phosphorylation levels of Lyn and Syk kinases, and Ca²⁺ influx were not inhibited. In contrast, lipid raft disruptor methyl-β-cyclodextrin attenuated the Ca²⁺ influx. Tagged-miltefosine rapidly localized into the cell interior, and live-cell imaging of BMMCs with labeled intracellular granules disclosed that miltefosine inhibited movement of some granules. Immunoprecipitation and in vitro kinase assays revealed that miltefosine inhibited Ca²⁺- and diacylglycerol-regulated conventional protein kinase C (cPKC) isoforms that are important for mast cell degranulation. Inhibition of cPKCs by specific inhibitor Ly333531 affected activation of BMMCs in the same way as miltefosine. Collectively, our data suggest that miltefosine modulates mast cells both at the plasma membrane and in the cytosol by inhibition of cPKCs. This alters intracellular signaling pathway(s) directed to microtubules, degranulation, and migration.

Alternative treatments for chronic spontaneous urticaria beyond the guideline algorithm

PURPOSE OF REVIEW

The international EAACI/GALEN/EDF/WAO guideline suggests a stepwise approach for the therapeutic management of chronic spontaneous urticaria (CSU), outlined in an algorithm. The aim of this article is to summarize and review the evidence available on alternative treatment options for CSU outside of this algorithm.

RECENT FINDINGS

Although CSU is a common disease, there are a limited number of high-quality studies, and only antihistamines and omalizumab are licensed for its treatment. Most studies regarding alternative therapies for CSU show methodological limitations and a high risk of bias. For many therapies, only case reports and uncontrolled studies exist. Recent publications on alternative treatments for chronic urticaria/CSU include reports on the use of adalimumab, rituximab, vitamin D, probiotics, histaglobulin, injection of autologous whole blood or serum, and phototherapy.

SUMMARY

Numerous treatments beyond the guideline algorithm have been evaluated in patients with refractory CSU. The global level of evidence to support their efficacy in CSU is low or very low. Further research is needed to assess the efficacy and safety of alternative therapies of CSU to manage adequately those patients who do not respond to the treatments included in the algorithm.

Comparison and interpretability of the available urticaria activity scores

The urticaria activity score (UAS) is the gold standard for assessing disease activity in patients with chronic spontaneous urticaria (CSU). Two different versions, the UAS7 and UAS7_TD , are currently used in clinical trials and routine care. To compare both versions and to obtain data on their interpretability, 130 CSU patients applied both versions and globally rated their disease activity as none, mild, moderate, or severe. UAS7 and UAS7_TD values correlated strongly (r = .90, P < .001). Interquartile ranges for UAS7 and UAS7TD values for mild, moderate, and severe CSU were 11-20 and 10-24, 16-30 and 16-32, and 27-37 and 28-40. UAS7 values were slightly, but significantly lower as compared to UAS7_TD values (mean difference: 1.6 ± 4.6, P < .001). This difference was driven by lower wheal subscores (2.1 ± 3.5, P < .001) and was most pronounced in patients with severe CSU (2.5 ± 5.6, P < .01). The UAS7/UAS7_TD ratio was 0.96 ± 0.21 and did not differ significantly between mild, moderate, and severe CSU. Since the results of both UAS versions are comparable, we recommend the use of the UAS7, which is less burdensome in administration and scoring.

Treatment of severely recalcitrant chronic spontaneous urticaria: a discussion of relevant issues

Chronic spontaneous urticaria (CSU) is a common disorder with a prevalence of 1% that is characterized by recurrent wheals, angioedema, or both. CSU is self-limited but in many patients symptoms recur for several years and can be refractory to standard therapies. In this review, we present an illustrative case of a female patient with CSU who, despite taking 15 antihistamines a day in addition to a number of second-line therapies, continued to be refractory to treatment. However, once we initiated subcutaneous treatment with omalizumab 300 mg every 4 weeks, she experienced rapid relief of her CSU symptoms. Through this case, we present a review of the relevant issues, including the efficacy of laboratory tests to identify the cause of a patient's CSU, the association between CSU and thyroid disease and its relevance to treatment options, the recommendation to increase antihistamine dose up to fourfold and possible adverse events associated with this treatment option. We also include a discussion of the use of second-line therapies as well as omalizumab in refractory CSU patients.

H1-antihistamines for chronic spontaneous urticaria

Background Chronic spontaneous urticaria (CSU) is characterised by the development of crops of red, itchy, raised weals or hives with no identifiable external cause.Objectives To assess the effects of H1-antihistamines for CSU.Search methods We searched the following databases up to June 2014: Cochrane Skin Group Specialised Register, CENTRAL (2014, Issue 5), MEDLINE(from 1946), EMBASE (from 1974) and PsycINFO (from 1806). We searched five trials registers and checked articles for references to relevant randomised controlled trials.Selection criteria We included randomised controlled trials of H1-antihistamines for CSU. Interventions included single therapy or a combination of H1-antihistamines compared with no treatment (placebo) or another active pharmacological compound at any dose.Data collection and analysis We used standard methodological procedures as expected by The Cochrane Collaboration.Our primary outcome measures were proportion of participants with complete suppression of urticaria: 'good or excellent' response,50% or greater improvement in quality of life measures, and adverse events.We present risk ratios (RR) with 95% confidence intervals(CIs). Main results We identified 73 studies (9759 participants); 34 studies provided data for 23 comparisons. The duration of the intervention was up to two weeks (short-term) or longer than two weeks and up to three months (intermediate-term).Cetirizine 10mg once daily in the short term and in the intermediate term led to complete suppression of urticaria by more participants than was seen with placebo (RR 2.72, 95% CI 1.51 to 4.91). For this same outcome, comparison of desloratadine versus placebo in the intermediate term (5 mg) (RR 37.00, 95% CI 2.31 to 593.70) and in the short term (20 mg) (RR 15.97, 95% CI 1.04 to 245.04)favoured desloratadine, but no differences were seen between 5 mg and 10 mg for short-term treatment.Levocetirizine 20 mg per day (short-term) was more effective for complete suppression of urticaria compared with placebo (RR 20.87,95% CI 1.37 to 317.60), and at 5 mg was effective in the intermediate term (RR 52.88, 95% CI 3.31 to 843.81) but not in the shortterm, nor was 10 mg effective in the short term.Rupatadine at 10 mg and 20 mg in the intermediate term achieved a 'good or excellent response' compared with placebo (RR 1.35,95% CI 1.03 to 1.77).Loratadine (10 mg) versus placebo (RR 1.86, 95% CI 0.91 to 3.79) and loratadine (10 mg) versus cetirizine (10 mg) (RR 1.05, 95%CI 0.76 to 1.43) over short-term and intermediate-term treatment showed no significant difference for 'good or excellent response' or for complete suppression of urticaria, respectively.Loratadine (10 mg) versus desloratadine (5 mg) (intermediate-term) showed no statistically significant difference for complete suppression of urticaria (RR 0.91, 95% CI 0.78 to 1.06) or for 'good or excellent response' (RR 1.04, 95% CI 0.64 to 1.71). For loratadine(10 mg) versus mizolastine (10 mg) (intermediate-term), no statistically significant difference was seen for complete suppression of urticaria (RR 0.86, 95% CI 0.64 to 1.16) or for 'good or excellent response' (RR 0.88, 95% CI 0.55 to 1.42).Loratadine (10mg) versus emedastine (2mg) (intermediate-term) showed no statistically significant difference for complete suppression(RR 1.04, 95% CI 0.78 to 1.39) or for 'good or excellent response' (RR 1.09, 95% CI 0.96 to 1.24); the quality of the evidence was moderate for this comparison.No difference in short-term treatment was noted between loratadine (10mg) and hydroxyzine (25mg) in terms of complete suppression(RR 1.00, 95% CI 0.32 to 3.10).When desloratadine (5 to 20 mg) was compared with levocetirizine (5 to 20 mg), levocetirizine appeared to be the more effective (P value < 0.02).In a comparison of fexofenadine versus cetirizine, more participants in the cetirizine group showed complete suppression of urticaria(P value < 0.001).Adverse events leading to withdrawals were not significantly different in the following comparisons: cetirizine versus placebo at 10 mg and 20 mg (RR 3.00, 95% CI 0.68 to 13.22); desloratadine 5 mg versus placebo (RR 1.46, 95% CI 0.42 to 5.10); loratadine 10 mg versus mizolastine 10 mg (RR 0.38, 95% CI 0.04 to 3.60); loratadine 10mg versus emedastine 2mg (RR 1.09, 95%CI 0.07 to 17.14);cetirizine 10 mg versus hydroxyzine 25 mg (RR 0.78, 95% CI 0.25 to 2.45); and hydroxyzine 25 mg versus placebo (RR 3.64, 95%CI 0.77 to 17.23), all intermediate term.No difference was seen between loratadine 10 mg versus mizolastine 10 mg in the proportion of participants with at least 50%improvement in quality of life (RR 3.21, 95% CI 0.32 to 32.33).Authors' conclusions Although the results of our review indicate that at standard doses of treatment, several antihistamines are effective when compared with placebo, all results were gathered from a few studies or, in some cases, from single-study estimates. The quality of the evidence was affected by the small number of studies in each comparison and the small sample size for many of the outcomes, prompting us to downgrade the quality of evidence for imprecision (unless stated for each comparison, the quality of the evidence was low).No single H1-antihistamine stands out as most effective. Cetirizine at 10 mg once daily in the short term and in the intermediate term was found to be effective in completely suppressing urticaria. Evidence is limited for desloratadine given at 5 mg once daily in the intermediate term and at 20 mg in the short term. Levocetirizine at 5 mg in the intermediate but not short term was effective for complete suppression. Levocetirizine 20 mg was effective in the short term, but 10 mg was not. No difference in rates of withdrawal due to adverse events was noted between active and placebo groups. Evidence for improvement in quality of life was insufficient.

Chronic urticaria: new management options

Chronic urticaria is defined as episodic or daily hives lasting for at least 6 weeks and impairs quality of life. Two main subtypes include chronic idiopathic (spontaneous) urticaria and inducible (physical) urticaria, but some patients have urticarial vasculitis. “Autoimmune chronic urticaria” implies the presence of histamine releasing or mast cell activating autoantibodies to IgE or FcϵRI, the high affinity receptor on mast cells and basophils. In patients not readily controlled with labeled dosages of second generation H₁ receptor antagonists (antihistamines), there is evidence for reduction of urticaria using up to 4 fold increases in labeled dosages. The biologic modifier, omalizumab, helps to reduce lesions of chronic urticaria within 1–2 weeks.

Update and insights into treatment options for chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is defined as itchy weals, angio-oedema, or both, arising spontaneously without external physical stimuli. Symptoms of the disease continue to develop for more than 6 weeks. It carries a high socioeconomic burden with considerable health care costs. Second generation H1-antihistamines are the mainstay of urticaria treatment and are the only licensed option. However, many patients are resistant to H1-antihistamine therapy. Omalizumab has proven to be an effective therapeutic option in patients with recalcitrant chronic urticaria. Ciclosporin appears to be more beneficial in patients with functional histamine releasing autoantibodies as a cause of their disease. This review article will highlight the major therapeutic options available today for the management of CSU knowing that good quality evidence for efficacy of many agents is scarce except for H1-antihistamines and omalizumab.

Repurposing miltefosine for the treatment of immune-mediated disease?

Miltefosine is an ether lipid that was initially developed for cancer treatment in the early 1980s. Miltefosine largely failed development for oncology, although it was approved for the topical treatment of breast cancer metastasis. It was subsequently discovered that miltefosine is a highly effective treatment of visceral Leishmaniasis, a parasitic disease that affects millions worldwide and causes an estimated 30,000 fatalities each year. Oral treatment with miltefosine is generally well tolerated and has relatively few adverse effects. The exact mechanism of action of miltefosine treatment is still under investigation. Its close resemblance to phospholipids allows it to be quickly taken up by cell membranes and affect related processes, such as lipid metabolism and signaling through lipid rafts. These processes play an important role in the immune response and it comes as no surprise that miltefosine has been successfully tested for the treatment of a number of immune-mediated diseases in preclinical models of disease. Drug repurposing of miltefosine for immune-mediated diseases may provide an opportunity to expand the limited number of drugs that are currently available for therapeutic use.

Treatment strategies in mastocytosis

Treatment recommendations for mastocytosis are based mostly on expert opinion rather than evidence obtained from controlled clinical trials. In this article, treatment options for mastocytosis are presented, with a focus on the control of mediator-related symptoms in patients with indolent disease.

Treatment of refractory chronic urticaria: current and future therapeutic options

Chronic urticaria is a distressing disease that affects up to 1 % of the general population at a time point in life and may severely worsen the quality of life. First-line treatment has been based on antihistamines, and presently relies on the use of non-sedating, second-generation antihistamines; following the recommendations of the recent international guidelines, in patients who do not respond to antihistamines at licensed doses, the daily dosage of these drugs can be increased up to fourfold. Nonetheless, a significant proportion of patients with chronic urticaria remain poorly controlled; in these cases, alternative therapeutic approaches have to be considered. This article critically reviews all of the third- and fourth-line treatment options suggested for patients whose disease is refractory to antihistamines, including systemic corticosteroids, leukotriene receptor antagonists, several different anti-inflammatory drugs (dapsone, sulfasalazine, hydroxychloroquine), various immunosuppressive drugs (calcineurin inhibitors, methotrexate, cyclophosphamide, azathioprine, mycophenolate mofetil), intravenous immunoglobulin, and newer treatment options, such as omalizumab and other biologic drugs. In addition, the article examines possible future treatment options based on recent findings about pathogenic mechanisms, and considers the treatment of antihistamine-unresponsive urticaria in special conditions such as children and pregnancy/lactation. The evidence supporting the use of several of the discussed drugs is presently limited and thus insufficient to recommend their routine use; as a consequence, such compounds should be considered only in specific cases and in adequate settings.