The new era of add-on asthma treatments: where do we stand?

The JAK-STAT pathway: from structural biology to cytokine engineering

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway serves as a paradigm for signal transduction from the extracellular environment to the nucleus. It plays a pivotal role in physiological functions, such as hematopoiesis, immune balance, tissue homeostasis, and surveillance against tumors. Dysregulation of this pathway may lead to various disease conditions such as immune deficiencies, autoimmune diseases, hematologic disorders, and cancer. Due to its critical role in maintaining human health and involvement in disease, extensive studies have been conducted on this pathway, ranging from basic research to medical applications. Advances in the structural biology of this pathway have enabled us to gain insights into how the signaling cascade operates at the molecular level, laying the groundwork for therapeutic development targeting this pathway. Various strategies have been developed to restore its normal function, with promising therapeutic potential. Enhanced comprehension of these molecular mechanisms, combined with advances in protein engineering methodologies, has allowed us to engineer cytokines with tailored properties for targeted therapeutic applications, thereby enhancing their efficiency and safety. In this review, we outline the structural basis that governs key nodes in this pathway, offering a comprehensive overview of the signal transduction process. Furthermore, we explore recent advances in cytokine engineering for therapeutic development in this pathway.

Patient and clinician preferences for biologic treatments for severe uncontrolled asthma: a discrete choice experiment (DCE)

OBJECTIVES

To estimate the preferences of patients with asthma and asthma-treating clinicians for attributes of biologic treatments, to compare patients' and clinicians' preferences, and to better understand the reasons for their preferences.

METHODS

Adults with moderate-to-severe asthma and clinicians who treat asthma in the US completed a cross-sectional, online survey including a discrete choice experiment (DCE) that consisted of seven attributes spanning treatment efficacy, risk and convenience. Marginal utilities were estimated using a mixed logit model, and relative attribute importance scores calculated. Clinicians were also asked about the value of biomarker agnostic biologic treatments. The survey was followed by qualitative interviews targeting a sub-sample of survey participants, in which the rationale behind their survey responses was discussed.

RESULTS

In the DCE, both patients and clinicians placed the most importance on exacerbation and hospitalization rate reduction, and risk of injection site reaction. Patients valued location of administration more than clinicians. Rationale for individual-level preferences varied, with patients and clinicians reporting their preference depended on event frequency and anticipated quality of life impacts. Clinicians mentioned compliance and financial impacts, while patients mentioned personal experience, particularly around site reactions. Most patients and clinicians would value a biomarker agnostic asthma treatment.

CONCLUSIONS

Asthma treatment preferences are largely driven by treatment efficacy and minimizing the risk of site reactions, although preferences differ between patients and clinicians across other attributes, highlighting the need for shared decision-making and individualized care.

Geographic and economic influences on benralizumab prescribing for severe asthma in Japan

Benralizumab, a monoclonal antibody targeting IL-5 receptors, reduces exacerbations and oral corticosteroid requirements for severe, uncontrolled eosinophilic asthma. In Japan, geographic disparities in asthma outcomes suggest differential prescribing and access. This study aimed to quantify regional prescribing variations for benralizumab nationwide. Using Japan's National Database (NDB) of insurance claims (2009-2019), benralizumab standardized claim ratios (SCRs) were calculated for 47 prefectures. Correlations between SCRs and other biologics' SCRs, economic variables like average income, and physician densities were evaluated through univariate analysis and multivariate regressions. Income-related barriers to optimal prescribing were examined. Wide variation emerged in benralizumab SCRs, from 40.1 to 184.2 across prefectures. SCRs strongly correlated with omalizumab (r = 0.61, p < 0.00001) and mepolizumab (r = 0.43, p = 0.0024). Average monthly income also positively correlated with benralizumab SCRs (r = 0.45, p = 0.0016), whereas lifestyle factors were insignificant. Respiratory specialist density modestly correlated with SCRs (r = 0.29, p = 0.047). In multivariate regressions, average income remained the most robust predictor (B = 0.74, p = 0.022). Benralizumab SCRs strongly associate with income metrics more than healthcare infrastructure/population factors. Many regions show low SCRs, constituting apparent prescribing gaps. Access barriers for advanced asthma therapies remain inequitable among Japan's income strata. Addressing affordability alongside specialist allocation can achieve better prescribing quality and asthma outcomes.

Navigating biologic therapies in elderly asthma

The prevalence of asthma among the elderly population has witnessed a notable rise, presenting unique challenges in diagnosis and management. Biologic therapies, such as omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, and tezepelumab, have demonstrated efficacy in targeting specific pathways associated with severe asthma in elderly individuals. However, a significant research gap exists in the application of these therapies in elderly asthma patients. Despite the considerable size of the elderly asthma population and the social and economic burden that this specific demographic imposes on society, the available body of research catering to this group is limited. Notably, no RCTs have been expressly designed for the elderly across all asthma biologic therapies. Moreover, most RCTs have set upper age cutoffs, commonly 75 years old, and exclusion criteria for common comorbidities in the elderly, thus marginalizing this group from pivotal research. This underscores the crucial need for intentional inclusion of elderly participants in separately designed clinical trials and more researches, aiming to augment the generalizability of findings and enhance therapeutic outcomes. Given the distinct physiological changes associated with aging, there may be a concern regarding the efficacy and safety of biologic therapies in the elderly compared to non-elderly adults, posing a barrier to their use in this population. However, observational studies have shown similar benefits of these therapies in elderly individuals as seen in non-elderly adults. Other anticipated challenges related to initiating biologic therapy in elderly people with asthma including dosing consideration and monitoring strategies, which are important areas of investigation for optimizing asthma management will be discussed in this review. In summary, this review navigates the current landscape of biologic therapies for elderly asthma, offering valuable insights for various stakeholders, including researchers, healthcare providers, and policymakers, to advance asthma care in this vulnerable population. We propose that future research should concentrate on tailored, evidence-based approaches to address the undertreatment of elderly asthma patients.

Sensitization with Fungal Protease Allergen Establishes Long-Lived, Allergenic Th Cell Memory in the Lung

Allergic asthma is a chronic inflammatory disease that affects millions of individuals worldwide. Exposure to allergens produced by a variety of otherwise harmless microbes, including fungi, predisposes individuals to immunopathologic disease upon subsequent encounters with allergen. We developed a mouse model that employs a purified protease produced by Aspergillus (Asp f 13) to investigate the contributions of CD4+ Th cells to recurrent lung inflammation. Notably, memory CD4+ T cells enhanced the eosinophil response of sensitized/rechallenged animals. In addition, memory CD4+ T cells maintained allergenic features, including expression of GATA-binding protein 3 and IL-5. Th2 memory T cells persisted in the peribronchiolar interstitium of the lung and expressed markers of tissue residence, such as CD69, CCR8, and IL-33R. Lastly, we identified a peptide epitope contained within Asp f 13 and generated a peptide-MHC class II tetramer. Using these tools, we further demonstrated the durability and exquisite sensitivity of memory T cells in promoting lung eosinophilia. Our data highlight important features of memory T cells that strengthen the notion that memory T cells are principal drivers of eosinophilic disease in murine models of allergic sensitization and episodic airway inflammation.

Current and Novel Biologic Therapies for Patients with Asthma and Nasal Polyps

A substantial portion of asthma and nasal polyps (NPs) share a common pathogenesis, which includes type 2-mediated inflammation. Distinct endotypes and phenotypes characterizing asthma and chronic rhinosinusitis have been identified. With emerging evidence describing pathophysiology, novel targets for biologic monoclonal antibody treatments have been developed. There are currently six biologic therapies approved by the US Food and Drug Administration to treat asthma, including omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, and tezepelumab, three of these-omalizumab, mepolizumab, and dupilumab-are also approved for NPs.

Engineering bispecific T-cell engagers to deplete eosinophils for the treatment of severe eosinophilic asthma

Severe eosinophilic asthma (SEA) is characterized by elevated eosinophil counts in the blood and airway mucosa. While monoclonal antibody therapies targeting interleukin-5 (IL-5) and its receptor (IL-5Rα) have improved treatment, some patients remain unresponsive. We propose an alternative approach to eliminate eosinophils using T cells by engineering IL-5Rα × CD3 bispecific T-cell engagers (bsTCEs) that target both IL-5Rα on eosinophils and CD3 on T cells. We designed different formats of IL-5Rα × CD3 bsTCEs, incorporating variations in valency, geometry, and affinity for the target antigen binding. We identified the single-chain variable fragment (scFv)-Fc format with the highest affinity toward the membrane-proximal domain of IL-5Rα in the IL-5Rα-binding arm showed the most potent cytotoxicity against IL-5Rα-expressing peripheral eosinophils by activating autologous primary T cells from healthy donors. This study proposes IL-5Rα × CD3 bsTCEs as potential alternatives for SEA treatment. Importantly, it demonstrates the first application of bsTCEs in eliminating disease-associated cells, including eosinophils, beyond cancer cells.

Key Considerations When Addressing Physical Inactivity and Sedentary Behaviour in People with Asthma

People with asthma tend to be less physically active and more sedentary than people without asthma. This narrative review aimed to present key considerations when addressing physical inactivity and sedentary behaviour in people with asthma by identifying barriers and facilitators, determinants and correlates, and intervention approaches. Using a search strategy, electronic databases were searched for relevant studies. Data extracted from studies were qualitatively synthesised. A total of 26 studies were included in the review. Six studies reported asthma symptoms as a barrier to physical activity, while four studies reported having a supportive network as a physical activity facilitator. Across studies, physical activity correlates/determinants were pulmonary function, exercise capacity, body mass index, dyspnoea, psychological health, and asthma control. Interventions that effectively improved physical activity in the short term were a step-based prescription programme, a weight loss programme incorporating aerobic and resistance training, and a weight loss lifestyle intervention, while a high-intensity interval training pulmonary rehabilitation program was effective in the long term. The collective findings suggest that a personalised physical activity programme incorporating different strategies is needed. There was minimal evidence to provide recommendations to optimise sedentary behaviour in asthma, and more research is needed on the topic.

Air Pollution and Diet: Potential Interacting Exposures in Asthma

PURPOSE OF REVIEW

To provide a review of emerging literature describing the impact of diet on the respiratory response to air pollution in asthma.

RECENT FINDINGS

Asthma phenotyping (observable characteristics) and endotyping (mechanistic pathways) have increased the specificity of diagnostic and treatment pathways and opened the doors to the identification of subphenotypes with enhanced susceptibility to exposures and interventions. Mechanisms underlying the airway immune response to air pollution are still being defined but include oxidative stress, inflammation, and activation of adaptive and innate immune responses, with genetic susceptibility highlighted. Of these, neutrophil recruitment and activation appear prominent; however, understanding neutrophil function in response to pollutant exposures is a research gap. Diet may play a role in asthma pathogenesis and morbidity; therefore, diet modification is a potential target opportunity to protect against pollutant-induced lung injury. In particular, in vivo and in vitro data suggest the potential for diet to modify the inflammatory response in the airways, including impacts on neutrophil recruitment and function. Murine models provide compelling results in regard to the potential for dietary components (including fiber, antioxidants, and omega-3 fatty acids) to buffer against the inflammatory response to air pollution in the lung. Precision lifestyle approaches to asthma management and respiratory protection in the context of air pollution exposures may evolve to include diet, pending the results of further epidemiologic and causal investigation and with neutrophil recruitment and activation as a candidate mechanism.

Regulatory T-cells in asthma

PURPOSE OF REVIEW

This review addresses recent progress in our understanding of the role of regulatory T (Treg) cells in enforcing immune tolerance and tissue homeostasis in the lung at steady state and in directing the immune response in asthmatic lung inflammation.

RECENT FINDINGS

Regulatory T cells regulate the innate and adaptive immune responses at steady state to enforce immune tolerance in lung tissues at steady state and their control of the allergic inflammatory responses induced by allergens. This regulatory function can break down in the context of chronic asthmatic airway inflammation such that the lung tissue Treg cells become skewed towards a pathogenic phenotype that aggravates and perpetuates disease. Subversion of lung tissue Treg cell function involves their upregulation of Notch4 expression, which in turn acts to amplify T helper type 2 and type 17 and innate lymphoid cell type 2 responses in the airways.

SUMMARY

A dual role for Treg cells has emerged both as immune regulators but also a potential disease effectors in asthma, with implications for disease therapy.

News in immunology

The field of immunology has undergone a very significant development in recent decades, which has been reflected especially in the beginning of this millennium in significant advances in the understanding of the immune system and in the application of this knowledge in practice. The progress and acceleration of research and advances in the field of immunology was further prompt by the unexpected onset of the COVID-19 pandemic in 2020. The intense scientific work has not only led to the development of our understanding of the immune response to viruses, but also to the rapid conversion of this knowledge into practical pandemic management on a global scale, as exemplified by the development of vaccines against SARS-Cov-2 virus. The pandemic era has further contributed to the acceleration of the application of not only biological discoveries but also technological approaches into practical applications, such as use of advanced mathematics, computer science and, more recently, artificial intelligence which are all are adding to the advances that are significantly moving the field of immunology forward. In this communication, we present specific advances in particular areas of immunopathology, which are mainly allergy, immunodeficiency, immunity and infection, vaccination, autoimmune diseases and cancer immunology.

Comparison between clinical trials and real-world evidence studies on biologics for severe asthma

In recent years, the more widespread availability of biological drugs with specific mechanisms of action has led to significant breakthroughs in the management of severe asthma. Over time, numerous randomised clinical trials have been conducted to evaluate the efficacy and safety of these biologics and define the eligibility criteria of patients suitable for various therapeutic options. These studies were conducted under controlled conditions not always applicable to real life. For this and other reasons, real-world evidence and pragmatic studies are required to provide useful information on the effectiveness of biological drugs and their safety, even in the long term. Because differences in outcomes have sometimes emerged between clinical trials and real-life studies, it is important to clarify the causes of these discrepancies and define the significance of the results of studies conducted in the course of daily clinical practice. Thus, a scientific debate is ongoing, and no consensus has been reached. The purpose of this narrative review is to analyse the differences between randomised trials and real-world evidence studies, focusing on their roles in guiding clinicians among different therapeutic options and understanding the reasons for the large discrepancies often found in the results obtained.