Add-on histamine receptor-3 antagonist for allergic rhinitis: a double blind randomized crossover trial using the environmental exposure unit

A Synopsis of Guidance for Allergic Rhinitis Diagnosis and Management From ICAR 2023

An updated edition of the International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR) has recently been published. This consensus document, which included the participation of 87 primary authors and 40 additional consultant authors, who critically appraised evidence on 144 individual topics concerning allergic rhinitis, provides guidance for health care providers using the evidence-based review with recommendations (EBRR) methodology. This synopsis highlights topical areas including pathophysiology, epidemiology, disease burden, risk and protective factors, evaluation and diagnosis, aeroallergen avoidance and environmental controls, single and combination pharmacotherapy options, allergen immunotherapy (subcutaneous, sublingual, rush, cluster), pediatric considerations, alternative and emerging therapies, and unmet needs. Based on the EBRR methodology, ICAR:AR includes strong recommendations for the treatment of allergic rhinitis: (1) for the use of newer generation antihistamines compared with first-generation alternatives, intranasal corticosteroid, intranasal saline, combination therapy with intranasal corticosteroid plus intranasal antihistamine for patients not responding to monotherapy, and subcutaneous immunotherapy and sublingual tablet immunotherapy in properly selected patients; (2) against the use of oral decongestant monotherapy and routine use of oral corticosteroids.

Histamine H3 receptor antagonists/inverse agonists: Where do they go?

Since the discovery of the histamine H₃ receptor in 1983, tremendous advances in the pharmacological aspects of H₃ receptor antagonists/inverse agonists have been accomplished in preclinical studies. At present, there are several drug candidates that reached clinical trial studies for various indications. However, entrance of these candidates to the pharmaceutical market is not free from challenges, and a variety of difficulties is engaged with their developmental process. In this review, the potential role of H₃ receptors in the pathophysiology of various central nervous system, metabolic and allergic diseases is discussed. Thereafter, the current status for H₃ receptor antagonists/inverse agonists in ongoing clinical trial studies is reviewed and obstacles in developing these agents are emphasized.

Modulation of Allergic Inflammation in the Nasal Mucosa of Allergic Rhinitis Sufferers With Topical Pharmaceutical Agents

Allergic rhinitis (AR) is a chronic upper respiratory disease estimated to affect between 10 and 40% of the worldwide population. The mechanisms underlying AR are highly complex and involve multiple immune cells, mediators, and cytokines. As such, the development of a single drug to treat allergic inflammation and/or symptoms is confounded by the complexity of the disease pathophysiology. Complete avoidance of allergens that trigger AR symptoms is not possible and without a cure, the available therapeutic options are typically focused on achieving symptomatic relief. Topical therapies offer many advantages over oral therapies, such as delivering greater concentrations of drugs to the receptor sites at the source of the allergic inflammation and the reduced risk of systemic side effects. This review describes the complex pathophysiology of AR and identifies the mechanism(s) of action of topical treatments including antihistamines, steroids, anticholinergics, decongestants and chromones in relation to AR pathophysiology. Following the literature review a discussion on the future therapeutic strategies for AR treatment is provided.

Progress in the development of histamine H3 receptor antagonists/inverse agonists: a patent review (2013-2017)

INTRODUCTION

Since years, ligands blocking histamine H₃ receptor (H₃R) activity (antagonists/inverse agonists) are interesting targets in the search for new cures for CNS disorders. Intensive works done by academic and pharmaceutical company researchers have led to many potent and selective H₃R antagonists/inverse agonists. Some of them have reached to clinical trials.

AREAS COVERED

Patent applications from January 2013 to September 2017 and the most important topics connected with H₃R field are analysed. Espacenet, Patentscope, Pubmed, GoogleScholar or Cochrane Library online databases were principially used to collect all the materials.

EXPERT OPINION

The research interest in histamine H₃R field is still high although the number of patent applications has decreased during the past 4 years (around 20 publications). Complexity of histamine H₃R biology e.g. many isoforms, constitutive activity, heteromerization with other receptors (dopamine D₂, D₁, adenosine A_2A) and pharmacology make not easy realization and evaluation of therapeutic potential of anti-H₃R ligands. First results from clinical trials have verified potential utility of histamine H₃R antagonist/inverse agonists in some diseases. However, more studies are necessary for better understanding of an involvement of the histaminergic system in CNS-related disorders and helping more ligands approach to clinical trials and the market. Lists of abbreviations: hAChEI - human acetylcholinesterase inhibitor; hBuChEI - human butyrylcholinesterase inhibitor; hMAO - human monoamine oxidase; MAO - monoamine oxidase.

Blood and nasal epigenetics correlate with allergic rhinitis symptom development in the environmental exposure unit

BACKGROUND

Epigenetic alterations may represent new therapeutic targets and/or biomarkers of allergic rhinitis (AR). Our aim was to examine genome-wide epigenetic changes induced by controlled pollen exposure in the environmental exposure unit (EEU).

METHODS

38 AR sufferers and eight nonallergic controls were exposed to grass pollen for 3 hours on two consecutive days. We interrogated DNA methylation at baseline and 3 hours in peripheral blood mononuclear cells (PBMCs) using the Infinium Methylation 450K array. We corrected for demographics, cell composition, and multiple testing (Benjamini-Hochberg) and verified hits using bisulfite PCR pyrosequencing and qPCR. To extend these findings to a clinically relevant tissue, we investigated DNA methylation and gene expression of mucin 4 (MUC4), in nasal brushings from a separate validation cohort exposed to birch pollen.

RESULTS

In PBMCs of allergic rhinitis participants, 42 sites showed significant DNA methylation changes of 2% or greater. DNA methylation changes in tryptase gamma 1 (TPSG1), schlafen 12 (SLFN12), and MUC4 in response to exposure were validated by pyrosequencing. SLFN12 DNA methylation significantly correlated with symptoms (P < 0.05), and baseline DNA methylation pattern was found to be predictive of symptom severity upon grass allergen exposure (P = 0.029). Changes in MUC4 DNA methylation in nasal brushings in the validation cohort correlated with drop in peak nasal inspiratory flow (Spearman's r = 0.314, P = 0.034), and MUC4 gene expression was significantly increased (P < 0.0001).

CONCLUSION

This study revealed novel and rapid epigenetic changes upon exposure in a controlled allergen challenge facility, and identified baseline epigenetic status as a predictor of symptom severity.

Efficacy of the novel nasal steroid S0597 tested in an environmental exposure unit

BACKGROUND

S0597 is a novel glucocorticosteroid that was formulated as an intranasal spray to treat seasonal allergic rhinitis (SAR). In a previous phase 2 study, doses of 100 to 400 μg twice daily were well tolerated and more effective than placebo for improving nasal symptoms induced by grass pollen.

OBJECTIVE

To assess the clinical efficacy and safety of a once-daily S0597 nasal spray for treatment of SAR induced by ragweed pollen in an environmental exposure unit (EEU).

METHODS

A single-center, phase 2, randomized, double-blind study in 222 adults with SAR and a positive skin prick test result to short ragweed. Participants underwent ragweed pollen challenge in the EEU at the screening or priming visit and on days 1, 7, and 14 and received 50, 200, or 400 μg of S0597 or placebo in the evening for 13 days. The primary efficacy end point was change in total nasal symptom score (TNSS) from baseline to day 14.

RESULTS

Improvement in TNSS from baseline to day 14 was statistically significant in all S0597 groups compared with placebo. Least-squares mean differences in change from baseline between active treatment and placebo were 1.18, 1.84, and 1.17 for the 50-, 200-, and 400-μg/d S0597 groups, respectively (P < .05). The 200-μg group demonstrated statistically significant improvements in all TNSS subscales (rhinorrhea, nasal congestion, sneezing, nasal itching) compared with placebo at days 7 and 14.

CONCLUSION

Treatment with 50 to 400 μg of S0597 once daily was well tolerated and significantly more effective than placebo in relieving nasal symptoms of SAR associated with ragweed pollen.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01940146.

Clinical validation of controlled exposure to birch pollen in the Environmental Exposure Unit (EEU)

BACKGROUND

The Environmental Exposure Unit (EEU) in Kingston, Ontario, Canada is a controlled allergen challenge facility (CACF) that has been previously clinically validated for the use of ragweed and grass pollen in clinical studies. In this study we aim to validate the use of birch pollen to challenge allergic participants.

METHODS

A total of 59 volunteers were screened and 38 birch allergic participants and ten non-allergics completed the study, outside of tree pollen season. Participants had to have a minimum of 2-year history of allergic rhinoconjunctivitis during the typical tree pollen season and have a positive skin prick test to birch allergen ≥5 mm from the control. Qualified participants were exposed to birch (Betula pendula) pollen for 4 h in the EEU and recorded their symptoms of sneezing, rhinorrhea, nasal congestion, nasal itch which comprised the total nasal symptom score (TNSS), as well as itchy/watery eyes, red/burning eyes and itching of ears/palate/throat which along with the TNSS comprised the total rhinoconjunctival symptom score (TRSS) along with Peak Nasal Inspiratory Flow (PNIF) at baseline and at 30 min intervals for the duration of exposure, then hourly for up to 12 h from the start of exposure.

RESULTS

Allergic participants reported a gradual rise in TNSS and TRSS, reaching a mean and standard error of the mean of 7.08 ± 0.45 and 11.58 ± 0.93 respectively by 180 min from the start of exposure. Symptoms gradually declined to near baseline values following departing from the unit, reaching 1.9 and 2.7 by 450 min. Allergic participants reported significantly higher TNSS than non-allergics starting from 30 min (p < 0.01, two-way ANOVA with Bonferroni corrections), maintaining maximum significance from 60 to 300 min (p < 0.0001) and losing significance by 420 min. TRSS and PNIF followed similar trends as those seen with TNSS. Participants were phenotyped using previously published definitions using the TNSS into Early Phase Responders (EPR, 57.8 %), protracted EPR (pEPR, 39.5 %), and Dual Phase Responders (DPR, 2.7 %).

CONCLUSIONS

The EEU can competently challenge birch allergic participants and achieve statistically significant changes in symptoms and nasal airflow, while such changes are not reported in non-allergic controls. Trial registration NCT02351830 clinicaltrials.gov.

Efficacy and safety of using a warming needle for persistent allergic rhinitis: study protocol for a randomized controlled trial

Background

Many previous studies have shown the potential therapeutic effect of acupuncture for allergic rhinitis. Most of these studies, however, were limited by the short duration of observations and lack of sham acupuncture as the control group. Our preliminary experiments showed that the use of a warm needling achieved a much more persistent effect in the treatment of allergic rhinitis (AR) compared with simple acupuncture therapy. Hence, we have designed a multicenter, randomized controlled trial (RCT) in which the first-line medication loratadine will be used as the control group, and the effect of warm needling therapy will be evaluated through long-term observation.

Methods/design

The trial is designed as a multicenter, parallel-group, randomized, single-blinded (outcome assessors), non-inferiority trial. A total of 98 patients with persistent AR will be randomly assigned into two groups. Patients in the treatment group will be treated with warm needling at GV14 and acupuncture at EX-HN3, ST2, LI20, EX-HN8, GV23, LU7, LU5 and LI4 three times a week, for a total of 4 weeks. Patients in the control group will be treated with oral loratadine 10 mg/day for 4 weeks. The primary outcome will be the change in the Total Nasal Symptom Score (TNSS) from baseline to that at 6 months after treatment during the follow-up period. The secondary outcomes will include the Total Non-nasal Symptom Score and the Rhinoconjunctivitis Quality of Life Questionnaire, changes in the TNSS from baseline to that at 2 and 4 weeks during treatment, and 3 months after treatment during the follow-up period. Outcomes will be measured at 2 and 4 weeks, and 3 and 6 months after treatment. Any side effects of treatment will be observed and recorded.

Discussion

We expect that the study results will provide evidence to determine the effects of warm needling compared with loratadine. Our final goal of the study is to evaluate the difference in the short-term and long-term effects between the two therapeutic methods, especially the long-term effect of warm needling.

Trial registration

ClinicalTrials.gov NCT02339714. Registered on 14 January 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1432-z) contains supplementary material, which is available to authorized users.

Novel, Alternative, and Controversial Therapies of Rhinitis

Rhinitis is a multifactorial disease characterized by sneezing, rhinorrhea, postnasal drip, and nasal congestion. This condition affects 10% to 40% of the population and is responsible for billions of spent health care dollars and impairment in quality of life for those affected. Currently available medical and vaccine therapies are effective for a large segment of this population; however, a subset of patients still has difficult-to-control rhinitis. This article reviews the current progress being made in novel drug and vaccine development and delves into alternative medical, surgical, and homeopathic strategies that may be promising adjunctive treatments for the difficult-to-treat rhinitis patient.

Emerging drugs for the treatment of perennial allergic rhinitis

INTRODUCTION

Allergic rhinitis is a worldwide health problem, currently affecting up to 40% of the general population, and characterized by the following symptoms in a variable degree of severity and duration: nasal congestion/obstruction, rhinorrhea, itchy nose and/or eyes, and/or sneezing. General symptoms like fatigue, reduced quality of sleep, impaired concentration and reduced productivity, if left untreated, may significantly affect quality of life. In addition, of being associated to various comorbidities, allergic rhinitis is also an independent risk factor for the development and worsening of asthma. Perennial allergic rhinitis is caused by allergens present around the year.

AREAS COVERED

Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines currently recommend a stepwise therapeutic approach that combines patient education with specific allergen avoidance, symptomatic pharmacotherapy and allergen immunotherapy. The available treatment strategies provide suboptimal symptom relief in patients with moderate-to-severe disease who continue to experience symptoms while treated, even on multiple therapies.

EXPERT OPINION

New insights into current therapy have been provided with the development of new symptomatic drugs with improved pharmacokinetics and safety. However, the ultimate research goal is beyond symptomatic treatment, and is mainly directed at modifying the immune response to allergens and prevent the progression of allergic rhinitis towards asthma. In this direction, promising advances are expected in the fields of allergen immunotherapy and biological drugs, such as omalizumab. Finally, significant research efforts are also focused on the growing number of new specific molecular targets involved in the Th2 pathway inflammation of allergic diseases.

Clinical validation of controlled grass pollen challenge in the Environmental Exposure Unit (EEU)

RATIONALE

The Environmental Exposure Unit (EEU), a controlled allergen exposure model of allergic rhinitis (AR), has traditionally utilized ragweed pollen. We sought to clinically validate the use of grass pollen in the EEU.

METHODS

Healthy volunteers with a history of AR symptoms during grass pollen season and supportive skin test responses attended the EEU for 3 hrs of rye grass pollen exposure (Lolium Perenne). Non-atopic controls were also recruited. Participants assessed individual rhinoconjunctivitis symptoms to generate Total Nasal Symptom Score (TNSS; max 12) and Total Symptom Score (TSS; max 24) and recorded Peak Nasal Inspiratory Flow (PNIF) q30min while in the EEU. Participants returned the following day for an additional 3 hrs of pollen exposure. Two separate groups allowed for the exploration of lower vs. higher pollen concentrations and subsequent effects on symptoms.

RESULTS

78 participants were screened, of whom 39 were eligible and attended the 2x3h EEU visits, plus 8 non-atopic controls. Mean TSS, TNSS and PNIF values amongst participants in the higher pollen concentration group (target 3500 grains/m3) after the first 3 hr exposure were 18.9, 9.7 and 68 L/min, respectively. In comparison, mean TSS, TNSS and PNIF values in the lower pollen concentration (2500 grains/m3) group were only 13.3, 7.6, and 82 L/min, respectively. The subsequent day of pollen exposure did not appreciably alter the maximal TSS/TNSSs, but rather resulted in a more rapid onset of symptomatology, with higher mean scores at the 30 min, 60 min and 90 min timepoints. The non-atopic controls remained asymptomatic.

CONCLUSIONS

This study provides clinical validation of the ability to generate allergic rhinoconjunctivitis symptoms amongst grass-allergic individuals in the EEU.