Fexofenadine: review of safety, efficacy and unmet needs in children with allergic rhinitis

Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Fexofenadine

In this monograph, the potential use of methods based on the Biopharmaceutics Classification System (BCS) framework to evaluate the bioequivalence of solid immediate-release (IR) oral dosage forms containing fexofenadine hydrochloride as a substitute for a pharmacokinetic study in human volunteers is investigated. We assessed the solubility, permeability, dissolution, pharmacokinetics, pharmacodynamics, therapeutic index, bioavailability, drug-excipient interaction, and other properties using BCS recommendations from the ICH, FDA and EMA. The findings unequivocally support fexofenadine's classification to BCS Class IV as it is neither highly soluble nor highly permeable. Further impeding the approval of generic equivalents through the BCS-biowaiver pathway is the reference product's inability to release ≥ 85 % of the drug substance within 30 min in pH 1.2 and pH 4.5 media. According to ICH rules, BCS class IV drugs do not qualify for waiving clinical bioequivalence studies based on the BCS, even though fexofenadine has behaved more like a BCS class I/III than a class IV molecule in pharmacokinetic studies to date and has a wide therapeutic index.

Twenty-five years: The fexofenadine clinical experience

Allergic rhinitis (AR) and urticaria affect a sizable portion of the population worldwide, resulting in reduced quality-of-life and productivity and increased healthcare costs. Fexofenadine (FEX) is a non-sedating second-generation H1 antihistamine with pronounced efficacy and a very good safety profile, used for the treatment of allergic diseases. In addition to its antihistaminic properties, FEX also has anti-inflammatory effects. FEX has a wide therapeutic window and is not associated with any sedative effects, even at higher than recommended doses. There is a need for an integrated management system for AR and urticaria which includes safe and effective treatment options. An ideal anti-allergic formulation should provide fast relief of symptoms and long-lasting effect without drowsiness. Data from randomized clinical trials show that FEX meets these criteria and is an effective treatment option with a favourable safety profile, improving the quality of life of patients suffering from AR and urticaria.

[Quality of life and sleep quality in patients with chronic pruritus]

Pruritus is defined as a symptom that leads to scratching. Clinically, a heterogeneous group of clinical pictures of different etiology must be considered. Pruritus is characterized by varying intensity and duration. Many patients and/or their social environment, which is influenced by this, cite the impact on sleep quality as an accompanying main symptom. The patient's quality of life is affected depending on the severity of the pruritus and often leads to comorbidity such as depressive disorders or sleep disorders as well as to an impact on psychosocial well-being if it becomes chronic. To date, in addition to the medical history, the established examination methods have been the determination of the disease burden by assessing disease activity, e.g., with validated disease-specific scores, plus the assessment of quality of life using a dermatological quality of life index (DLQI). The latest studies show that this is by no means sufficient to determine the severity of disease and, as a result, to identify adequate treatment options.

Why fexofenadine is considered as a truly non-sedating antihistamine with no brain penetration: a systematic review

OBJECTIVE

Fexofenadine is a second-generation inverse agonist of H1-receptor of histamine which is highly selective with proven efficacy in relieving symptoms associated with allergic conditions. It has an additional benefit of not penetrating the blood-brain barrier and therefore do not induce sedation and not impair the cognitive function/psychomotor performance. This review aimed at providing evidence based on available controlled studies to reinforce the non-sedative property of fexofenadine for treating patients with allergic rhinitis and urticaria.

METHODS

We performed an electronic literature search using keywords such as fexofenadine, drowsiness, somnolence, sedation, fatigue, cognitive, impairment, psychomotor, driving performances, sleep, rapid eye movement, alertness, clinical study, in vitro study, in vivo study, and pharmacodynamics in the Embase search engine. The review included randomized controlled trials, review articles, systematic reviews, and meta-analyses, together with post-marketing analysis conducted in healthy subjects and patients with allergy and were focused on comparing the antihistaminic potential or safety of fexofenadine with other antihistamines or placebo.

RESULTS

Positron emission tomography (PET) and proportional impairment ratio (PIR) data along with other objective tests from various studies confirmed the non-sedative property of fexofenadine. Results of brain H1-receptor occupancy (H1RO) obtained from PET showed no H1RO by fexofenadine, the receptor which is known to cause sedation of H1 antihistamines. Most studies calculating PIR value as 0 showed fexofenadine to be a non-impairing oral antihistamine regardless of dose. Clinical trials in adults and children showed fexofenadine to be well tolerated without sedative effect or impairment of cognitive/psychomotor function even at higher than recommended doses.

CONCLUSION

Published literature based on various parameters and clinical trials conducted for evaluating the effect of fexofenadine on sedation and central nervous system shows fexofenadine is both clinically effective and non-sedating.

Development of fexofenadine self-microemulsifying delivery systems: an efficient way to improve intestinal permeability

Aim: The present study aimed to prepare and evaluate fexofenadine self-microemulsifying drug-delivery systems (SMEDDS) formulation and to determine and compare its intestinal permeability using in situ single-pass intestinal perfusion (SPIP) technique.Methods: Fexofenadine-loaded SMEDDS were prepared and optimized. Droplet size, polydispersity index, zeta potential, drug release and intestinal permeability were evaluated.Results: Optimized formulation consisted of 15% oil, 80% surfactant and 5% cosolvent. Droplet size and drug loading of optimized formulation was 13.77 nm and 60 mg/g and it has released 90% of its drug content. Intestinal permeability of fexofenadine was threefold enhanced in SMEDDS compared with free fexofenadine.Conclusion: The results of our study revealed that SMEDDS could be a promising tool for oral delivery of fexofenadine with enhanced dissolution rate and intestinal permeability.

Establishment of a human nasal epithelium model of histamine-induced inflammation to assess the activity of fexofenadine as an inverse agonist and its link to clinical benefit

Background

Fexofenadine (FEX) is an antihistamine that acts as an inverse agonist against histamine (HIS) receptor 1 (H1R), which mediates the allergic reaction. Inverse agonists may be more potent than neutral antagonists, as they bind the same receptor as the agonist (HIS) but stabilize the inactive form and induce an opposite pharmacological response, suppressing the basal activity of H1R and preventing HIS from binding. This study aims to establish and validate a model of HIS-induced inflammation based on fully reconstituted human nasal epithelial tissue to assess the activity of FEX as an inverse agonist in this model and explore its link to clinical benefit.

Methods

The model was developed using nasal MucilAir™ (Epithelix) in vitro epithelium challenged by HIS. Two conditions were assessed in a side-by-side comparison: tissue was exposed to HIS + FEX with or without FEX pre-treatment (one-hour prior to HIS challenge). Tissue functionality, cytotoxicity, H1R gene expression, and inflammatory cytokines were assessed.

Results

HIS at 100 µM induced significant 3.1-fold and 2.2-fold increases for inflammatory biomarkers interleukin (IL)-8 and IL-6, respectively (p < 0.0001), as well as rapid upregulation of H1R mRNA. Inflammatory biomarkers were inhibited by FEX and H1R expression was significantly reduced (p < 0.0001). FEX alone decreased H1R expression at all doses tested. With one-hour FEX pre-treatment, there was significantly higher downregulation of IL-8 (p < 0.05) and further downregulation of H1R expression and IL-6 versus without FEX pre-treatment; the effects of FEX were improved from 22% to 40%.

Conclusion

A model of HIS-induced airway inflammation was established based on IL-8, IL-6 and H1R gene expression and was validated with FEX. FEX works as an inverse agonist, with a higher effect when used before+during versus only during the HIS challenge. Taking FEX before+during allergen exposure, or when symptoms first occur, may reduce basal activity and H1R gene expression, providing stronger protection against the worsening of symptoms upon allergen exposure.

Integration of National Health Insurance claims data and animal models reveals fexofenadine as a promising repurposed drug for Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a common and costly progressive neurodegenerative disease of unclear etiology. A disease-modifying approach that can directly stop or slow its progression remains a major unmet need in the treatment of PD. A clinical pharmacology-based drug repositioning strategy is a useful approach for identifying new drugs for PD.

METHODS

We analyzed claims data obtained from the National Health Insurance Service (NHIS), which covers a significant portion of the South Korean population, to investigate the association between antihistamines, a class of drugs commonly used to treat allergic symptoms by blocking H1 receptor, and PD in a real-world setting. Additionally, we validated this model using various animal models of PD such as the 6-hydroxydopmaine (6-OHDA), α-synuclein preformed fibrils (PFF) injection, and Caenorhabditis elegans (C. elegans) models. Finally, whole transcriptome data and Ingenuity Pathway Analysis (IPA) were used to elucidate drug mechanism pathways.

RESULTS

We identified fexofenadine as the most promising candidate using National Health Insurance claims data in the real world. In several animal models, including the 6-OHDA, PFF injection, and C. elegans models, fexofenadine ameliorated PD-related pathologies. RNA-seq analysis and the subsequent experiments suggested that fexofenadine is effective in PD via inhibition of peripheral immune cell infiltration into the brain.

CONCLUSION

Fexofenadine shows promise for the treatment of PD, identified through clinical data and validated in diverse animal models. This combined clinical and preclinical approach offers valuable insights for developing novel PD therapeutics.

Highlights of the treatment of allergic rhinitis according to Chinese guidelines

PURPOSE OF REVIEW

This review aimed to introduce the pharmacotherapy of allergic rhinitis according to the 2022 updated Chinese guidelines.

RECENT FINDINGS

Despite recent advances in basic and clinical research worldwide, pharmacotherapy remains a mainstream in allergic rhinitis treatment. Usually, the first-line drugs, involving intranasal corticosteroids, second-generation oral and intranasal H1-antihistamines, or leukotriene receptor antagonists, can achieve acceptable outcomes in the treatment of allergic rhinitis. The second-line drugs, such as oral corticosteroids, intranasal decongestants and intranasal anticholinergics, can assist in controlling severe symptoms, like nasal congestion/blockage and watery rhinorrhea. For those with moderate-to-severe allergic rhinitis, evidence-based stepwise strategies are suitable, in which the types and dosages of drugs are de-escalated or upgraded according to their therapeutic efficacy. Meanwhile, omalizumab, a novel biological agent, has burgeoned to satisfy the need of patients.

SUMMARY

This review highlights the staples in Chinese guidelines about the pharmacotherapy for allergic rhinitis to better understand the guidelines and promote the clinical practice.

Update meta-analysis on the efficacy and safety issues of fexofenadine

Background

Fexofenadine emerged as one of the most representative second generation histamine H1 antagonist drugs since the 1990s, with an outstanding efficacy and appreciable safety for the treatment of allergic patients. While allergic rhino-conjunctivitis represents the most frequent atopic disease globally, an update of fexofenadine efficacy and safety on this entity was proposed as a surrogate of allergic condition.

Methods

Double blind, placebo controlled, randomized clinical trials investigating the efficacy and safety of fexofenadine for the treatment of Allergic Rhinitis were searched in 5 major global databases. Eligibility criteria and characteristics, risk of bias, and validity assessment, data extraction and heterogeneity evaluation are described. Primary outcome selected corresponded to 12-reflective and instantaneous total symptom scores (TSS), besides morning instantaneous TSS and the frequency of reported adverse events (AEs); analysis was planned on the intention-to-treat population.Standardized mean differences of scoring systems were analyzed, and Cochran's Q statistic test and the I2 test were assessed for heterogeneity.

Results

From the initial 83 identified records, 12 eligible studies were selected. In the evaluated patients, individuals receiving fexofenadine (1910) showed a significant reduction of TSS compared with those who received placebo (1777), change from baseline: standardized mean difference (SMD) -0.33; 95% CI-0.47 to -0.18, p < 0.0001. Morning instantaneous TSS also demonstrated lower symptoms (change from baseline: SMS -1.42; 95% CI -2.22 to -0.62, p = 0.0005). Heterogeneity was found across selected studies.Frequency of AEs was similar compared to placebo (OR = 1.04; 0.88-1.21), with no detection of heterogeneity across these 12 studies.

Conclusions

According to this new evidence, fexofenadine maintains its beneficial profile on signs and symptoms of patients with allergic conditions, as well as its attributes as one of the major candidates for an ideal antihistamine medication (including special conditions such as pregnancy and pre-school age), providing support to its over-the-counter condition in several countries.

Pollen respiratory allergy: Is it really seasonal?

Allergic rhinitis (AR) is a highly prevalent respiratory condition that carries a heavy burden and can have a significant impact on patient quality of life. AR is caused by seasonal or perennial exposure to outdoor pollens and molds as well as indoor allergic triggers. In this review article, we discuss the factors associated with the development of AR throughout the year and the fact that patients with AR need continuous treatment rather than seasonal treatment. Conventionally, AR has been mainly categorized into seasonal AR and perennial AR, but these classes do not seem to be well-adapted. Climate changes, temperature changes, and high carbon dioxide (CO₂) concentration affect the growth of plants and increase the length of pollen seasons and pollen allergenicity. Air pollution aggravates allergic sensitization symptoms in AR sensitized individuals. Due to increased air pollution and indefinite pollen seasons AR symptoms are present throughout the year. Patients with AR often need continuous treatment, which should be considered while making the strategy for treating allergic rhinitis sufferers. Management of AR involves avoiding the allergen, medications for symptomatic relief, anti-inflammatory therapies, and allergy immunotherapy. Although the first-generation H₁-antihistamines reduce AR symptoms, they cause sedation and impair cognitive functions; thus, second-generation antihistamines (ie, levocetirizine, loratadine, bilastine, fexofenadine) are preferred. The efficacy and safety of fexofenadine for the treatment of seasonal allergic rhinitis (SAR) symptoms have been demonstrated by numerous clinical studies, irrespective of the season and underlying allergen. In this review, we discuss the allergic rhinitis classification, the role of climate change, air pollution, and factors contributing to year-round symptoms in patients with AR and the need for continuous pharmacological treatment for management.

Intranasal Anticholinergics for Treatment of Chronic Rhinitis: Systematic Review and Meta-Analysis

OBJECTIVE

Topical intranasal anticholinergics are commonly prescribed for the relief of chronic rhinitis and associated symptoms, warranting thorough assessment of the supporting evidence. The present study aimed to evaluate the safety and efficacy of anticholinergic nasal sprays in the management of allergic and non-allergic rhinitis symptom severity and duration.

METHODS

A search encompassing the Cochrane Library, PubMed/MEDLINE, and Scopus databases was conducted. Primary studies describing rhinorrhea, nasal congestion, and/or postnasal drip outcomes in rhinitis patients treated with an anticholinergic spray were included for review.

RESULTS

The search yielded 1,029 unique abstracts, of which 12 studies (n = 2,024) met inclusion criteria for qualitative synthesis and 9 (n = 1,920) for meta-analysis. Median follow-up was 4 weeks and ipratropium bromide was the most extensively trialed anticholinergic. Compared to placebo, anticholinergic treatment was demonstrated to significantly reduce rhinorrhea severity scores (standardized mean difference [95% CI] = -0.77 [-1.20, -0.35]; -0.43 [-0.72, -0.13]) and duration (-0.62 [-0.95, -0.30]; -0.29 [-0.47, -0.10]) in allergic and non-allergic rhinitis patients respectively. Benefit was less consistent for nasal congestion, postnasal drip, and sneezing symptoms. Reported adverse effects included nasal mucosa dryness or irritation, epistaxis, headaches, and pharyngitis, though comparison to placebo found significantly greater risk for epistaxis only (risk ratio [95% CI] = 2.19 [1.22, 3.93]).

CONCLUSION

Albeit treating other symptoms with less benefit, anticholinergic nasal sprays appear to be safe and efficacious in reducing rhinorrhea severity and duration in both rhinitis etiologies. This evidence supports their continued use in the treatment of rhinitis-associated rhinorrhea.

LEVEL OF EVIDENCE

1 Laryngoscope, 133:722-731, 2023.

An Explainable Knowledge-Based System Using Subjective Preferences and Objective Data for Ranking Decision Alternatives

BACKGROUND

 Allergy is a hypersensitive reaction that occurs when the allergen reacts with the immune system. The prevalence and severity of the allergies are uprising in South Asian countries. Allergy often occurs in combinations which becomes difficult for physicians to diagnose.

OBJECTIVES

 This work aims to develop a decision-making model which aids physicians in diagnosing allergy comorbidities. The model intends to not only provide rational decisions, but also explainable knowledge about all alternatives.

METHODS

 The allergy data gathered from real-time sources contain a smaller number of samples for comorbidities. Decision-making model applies three sampling strategies, namely, ideal, single, and complete, to balance the data. Bayes theorem-based probabilistic approaches are used to extract knowledge from the balanced data. Preference weights for attributes with respect to alternatives are gathered from a group of domain-experts affiliated to different allergy testing centers. The weights are combined with objective knowledge to assign confidence values to alternatives. The system provides these values along with explanations to aid decision-makers in choosing an optimal decision.

RESULTS

 Metrics of explainability and user satisfaction are used to evaluate the effectiveness of the system in real-time diagnosis. Fleiss' Kappa statistic is 0.48, and hence the diagnosis of experts is said to be in moderate agreement. The decision-making model provides a maximum of 10 suitable and relevant pieces of evidence to explain a decision alternative. Clinicians have improved their diagnostic performance by 3% after using CDSS (77.93%) with a decrease in 20% of time taken.

CONCLUSION

 The performance of less-experienced clinicians has improved with the support of an explainable decision-making model. The code for the framework with all intermediate results is available at https://github.com/kavya6697/Allergy-PT.git.