Phase 1 trial supports safety and mechanism of action of peptide immunotherapy for peanut allergy

BACKGROUND

Food allergy is a leading cause of anaphylaxis worldwide. Allergen-specific immunotherapy is the only treatment shown to modify the natural history of allergic disease, but application to food allergy has been hindered by risk of severe allergic reactions and short-lived efficacy. Allergen-derived peptides could provide a solution. PVX108 comprises seven short peptides representing immunodominant T-cell epitopes of major peanut allergens for treatment of peanut allergy.

METHODS

Pre-clinical safety of PVX108 was assessed using ex vivo basophil activation tests (n = 185). Clinical safety and tolerability of single and repeat PVX108 doses were evaluated in a first-in-human, randomized, double-blind, placebo-controlled trial in peanut-allergic adults (46 active, 21 placebo). The repeat-dose cohort received six doses over 16 weeks with safety monitored to 21 weeks. Exploratory immunological analyses were performed at pre-dose, Week 21 and Month 18 after treatment.

RESULTS

PVX108 induced negligible activation of peanut-sensitised basophils. PVX108 was safe and well tolerated in peanut-allergic adults. There were no treatment-related hypersensitivity events or AEs of clinical concern. The only events occurring more frequently in active than placebo were mild injection site reactions. Exploratory immunological analyses revealed a decrease in the ratio of ST2+ Th2A:CCR6+ Th17-like cells within the peanut-reactive Th pool which strengthened following treatment.

CONCLUSION

This study supports the concept that PVX108 could provide a safe alternative to whole peanut immunotherapies and provides evidence of durable peanut-specific T-cell modulation. Translation of these findings to clinical efficacy in ongoing Phase 2 trials would provide important proof-of-concept for using peptides to treat food allergy.

POS0111 MORE METICULOUSLY FOLLOWING TREAT-TO-TARGET IN RA DOES NOT LEAD TO LESS RADIOGRAPHIC PROGRESSION: A LONGITUDINAL ANALYSIS IN BIODAM

Background

A Treat-to-Target approach (T2T) is broadly considered to lead to better clinical outcomes and recommended in patients with RA. However, very few studies have analyzed the effect of T2T on radiographic progression, and any such studies have provided inconsistent results.

Objectives

To investigate whether meticulously following a treat-to-target (T2T)-strategy in daily clinical practice leads to lower radiographic progression in RA.

Methods

Patients from the multicenter RA-BIODAM cohort with ≥2 consecutive visits with radiographs available were included. In RA-BIODAM patients were enrolled as they were initiating a new csDMARD/bDMARD treatment were followed-up with the intention to benchmark and intensify treatment. The primary outcome of this analysis was the change in Sharp-van der Heijde score (SvdH, 0-448), assessed every 6 months, using average scores from 2 readers (scores with known chronological order). Following a DAS44-T2T remission strategy, which was defined at each 3-month visit, was the main variable of interest. Patients were categorized based on the proportion of visits in which T2T was followed according to our definition: very low (≤40% of the visits, low (>40%, <62.5%), high (≥62.5%, ≤75%) and very high (>75%). Radiographic progression at 2 years was visualized across groups by cumulative probability plots. Per 3-month interval T2T could be followed zero, one or two times (in a total of 2 visits). Associations between the number of visits with T2T in an interval and radiographic progression, both in the same and in the subsequent 6-month interval, were analysed by generalised estimating equations, adjusted for age, gender, disease duration and country.

Results

In total, 511 patients were included (mean (SD) age: 56 (13) years; 76% female). After 2 years, patients showed on average 2.2 (4.1) units progression (median:1 unit). Mean (SD) 2-year progression was not significantly different across categories of T2T: very low: 2.1 (2.7)-units; low: 2.8 (6.0); high: 2.4 (4.5), very high: 1.6 (2.2) (Figure 1). Meticulously following-up T2T in a 3-month interval neither reduced progression in the same 6-month interval (parameter estimates (for yes vs no): +0.15 units (95%CI: -0.04 to 0.33) for 2 vs 0 visits; and +0.08 units (-0.06;0.22) for 1 vs 0 visits) nor did it reduce progression in the subsequent 6-month interval (Table 1).

Table 1.

Effect of following DAS44-remission-T2T strategy on 6-month radiographic progression over 2 years

Change in radiographic damage(regression coefficient (95% CI))N=506T2T during 3 months on radiographic progression in the same 6-month period 2 visits vs 0 followed0.15 (-0.04; 0.33) 1 visit vs 0 followed0.08 (-0.06; 0.22)T2T during 3 months on radiographic progression in the subsequent 6-month period 2 visits vs 0 followed-0.09 (-0.28; 0.10) 1 visit vs 0 followed-0.10 (-0.24; 0.05)Figure 1.

Cumulative probability plot with 2-year radiographic progression according to the proportion of 3-monthly visits with T2T followed

Conclusion

In this daily practice cohort, more meticulously following T2T principles did not result in more reduction of radiographic progression than a somewhat more liberal attitude toward T2T. One possible interpretation of these results is that the intention to apply T2T already suffices and that a more stringent approach does not further improve outcome.

Acknowledgements

BIODAM was financially supported by an unrestricted grant from AbbVie

Disclosure of Interests

Sofia Ramiro Speakers bureau: Eli Lilly, MSD, Novartis, UCB, Consultant of: AbbVie, Eli Lilly, MSD, Novartis, Pfizer, UCB, Sanofi, Grant/research support from: AbbVie, Galapagos, Novartis, Pfizer, UCB, Robert B.M. Landewé Speakers bureau: AbbVie, BMS, Gilead, Galapagos, GSK,Janssen, Lilly, Novartis, Pfizer, UCB, Consultant of: AbbVie, BMS, Gilead, Galapagos, GSK,Janssen, Lilly, Novartis, Pfizer, UCB

Dr Landewé owns Rheumatology Consultancy BV, Désirée van der Heijde Consultant of: AbbVie, Bayer, BMS, Cyxone, Eisai, Galapagos, Gilead, Glaxo-Smith-Kline, Janssen, Lilly, Novartis, Pfizer, UCB Pharma. Director of Imaging Rheumatology bv., Alexandre Sepriano Speakers bureau: Novartis, Consultant of: UCB, Oliver FitzGerald Speakers bureau: Biogen, Novartis, AbbVie, BMS, Pfizer, Grant/research support from: BMS, Novartis, UCB, Pfizer, Lilly, Janssen, Mikkel Østergaard Speakers bureau: Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, Merck, Novartis, Orion, Pfizer, Roche and UCB, Consultant of: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Grant/research support from: Abbvie, Amgen, BMS, Merck, Celgene and Novartis, Joanne Homik: None declared, Ori Elkayam Speakers bureau: Pfizer, Lilly, Novartis, Abbvie, BI, Janssen, Consultant of: Pfizer, Lilly, Novartis, Abbvie, BI, Janssen, Grant/research support from: Pfizer, Abbvie, Janssen, Carter Thorne Consultant of: Abbvie, Organon, Pfizer, Sandoz, Maggie Larché Speakers bureau: AbbVie, Actelion, Amgen, BMS, Boehringer-Ingelheim, Fresenius-Kabi, Gilead, Janssen, Mallinckrodt, Merck, Novartis, Pfizer, Roche, Sandoz, Sanofi, Sobi, UCB, Grant/research support from: Abbvie, BMS, Gianfranco Ferraccioli Speakers bureau: SOBI, Consultant of: Abbivie, Marina Backhaus: None declared, Gilles Boire Speakers bureau: Abbvie Canada, BMS Canada, Lilly Canada, Janssen Canada, Merck Canada, Pfizer Canada, Viatris, Consultant of: Abbvie Canada, Amgen Canada, BMS Canada, Celgene, GileadSciences, Janssen Canada, Lilly Canada, Merck Canada, Mylan Canada, Novartis Canada, Pfizer Canada, Roche Canada, Samsung Bioepis, Sanofi Canada, Teva, Grant/research support from: Lilly Canada, BMS Canada, Pfizer, Sandoz Canada, UCB Canada, Merck Canada, Novartis Canada, Roche Canada, Bernard Combe Speakers bureau: Abbvie, BMS,Celltrion,Galapgos-Gilead, Janssen, Lilly, MERCK, Pfizer,Roche-Chugai, Consultant of: Abbvie, Celltrion,Galapgos-Gilead, Janssen, Lilly, MERCK, Roche-Chugai, Grant/research support from: Pfizer, Roche-chugai, Thierry Schaeverbeke: None declared, Alain Saraux Speakers bureau: Abbvie, Lilly, Nordic, Novartis, Pfizer, Roche-Chugai, Sanofi, UCB, Consultant of: Abbvie, Lilly, Nordic, Novartis, Pfizer, Roche-Chugai, UCB, Grant/research support from: Novartis, Fresenius, Lilly, Maxime Dougados Consultant of: Pfizer, AbbVie, UCB, Merck, Lilly, Novartis, BMS, Galapagos, Biogen, Roche, Grant/research support from: Pfizer, AbbVie, UCB, Merck, Lilly, Novartis, BMS, Galapagos, Biogen, Roche, Maurizio Rossini Speakers bureau: Amgen, Abbvie, BMS, Eli-Lilly, Galapagos,MSD, Novartis, Pfizer, Sandoz, Theramex, UCB, Marcello Govoni Speakers bureau: Abbvie, Pfizer, Galapagos, BMS, Eli-Lilly, Paid instructor for: Pfizer, Consultant of: Abbvie, BMS, Novartis, Astrazeneca, Pfizer, Luigi Sinigaglia: None declared, Alain Cantagrel Speakers bureau: Abbvie, Amgen, Biogen, BMS, Janssen, Lilly France, Médac, MSD France, Nordic-Pharma, Novartis, Pfizer, Sanofi Aventis, UCB, Consultant of: BMS, Janssen, Lilly France, MSD France, Sandoz, Grant/research support from: MSD France, Novartis, Pfizer, Cornelia Allaart: None declared, Cheryl Barnabe Speakers bureau: Sanofi Genzyme, Pfizer, Fresenius Kabi, Janssen, Consultant of: Gilead, Celltrion Healthcare, Clifton Bingham Consultant of: AbbVie, BMS, Eli Lilly, Janssen, Moderna, Pfizer, Sanofi, Grant/research support from: BMS, Dirkjan van Schaardenburg: None declared, Hilde Berner Hammer Speakers bureau: AbbVie, Novartis, Lilly, Rana Dadashova: None declared, Edna Hutchings: None declared, Joel Paschke: None declared, Walter P Maksymowych Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, UCB, Consultant of: Abbvie, Boehringer Ingelheim, Celgene, Eli-Lilly, Galapagos, Novartis, Pfizer, UCB, Grant/research support from: Abbvie, Novartis, Pfizer

One hundred and ten years of Allergen Immunotherapy: A journey from empiric observation to evidence

One hundred and ten years after Noon's first clinical report of the subcutaneous application of allergen extracts, allergen immunotherapy (AIT) has evolved as the most important pillar of the treatment of allergic patients. It is the only disease-modifying treatment option available and the evidence for its clinical efficacy and safety is broad and undisputed. Throughout recent decades, more insights into the underlying mechanisms, in particular the modulation of innate and adaptive immune responses, have been described. AIT is acknowledged by worldwide regulatory authorities, and following the regulatory guidelines for product development, AIT products are subject to a rigorous evaluation before obtaining market authorization. Knowledge and practice are anchored in international guidelines, such as the recently published series of the European Academy of Allergy and Clinical Immunology (EAACI). Innovative approaches continue to be further developed with the focus on clinical improvement by, for example, the usage of adjuvants, peptides, recombinants, modification of allergens, new routes of administration, and the concomitant use of biologicals. In addition, real-life data provide complementary and valuable information on the effectiveness and tolerability of this treatment option in the clinical routine. New mobile health technologies and big-data approaches will improve daily treatment convenience, adherence, and efficacy of AIT. However, the current coronavirus disease 2019 (COVID-19) pandemic has also had some implications for the feasibility and practicability of AIT. Taken together, AIT as the only disease-modifying therapy in allergic diseases has been broadly investigated over the past 110 years laying the path for innovations and further improvement.

Technical standards in allergen exposure chambers worldwide - an EAACI Task Force Report

Allergen exposure chambers (AECs) can be used for controlled exposure to allergenic and non-allergenic airborne particles in an enclosed environment, in order to (i) characterize the pathological features of respiratory diseases and (ii) contribute to and accelerate the clinical development of pharmacological treatments and allergen immunotherapy for allergic disease of the respiratory tract (such as allergic rhinitis, allergic rhinoconjunctivitis, and allergic asthma). In the guidelines of the European Medicines Agency for the clinical development of products for allergen immunotherapy (AIT), the role of AECs in determining primary endpoints in dose-finding Phase II trials is emphasized. Although methodologically insulated from the variability of natural pollen exposure, chamber models remain confined to supporting secondary, rather than primary, endpoints in Phase III registration trials. The need for further validation in comparison with field exposure is clearly mandated. On this basis, the European Academy of Allergy and Clinical Immunology (EAACI) initiated a Task Force in 2015 charged to gain a better understanding of how AECs can generate knowledge about respiratory allergies and can contribute to the clinical development of treatments. Researchers working with AECs worldwide were asked to provide technical information in eight sections: (i) dimensions and structure of the AEC, (ii) AEC staff, (iii) airflow, air processing, and operating conditions, (iv) particle dispersal, (v) pollen/particle counting, (vi) safety and non-contamination measures, (vii) procedures for symptom assessments, (viii) tested allergens/substances and validation procedures. On this basis, a minimal set of technical requirements for AECs applied to the field of allergology is proposed.

T cell-mediated autoimmunity in immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count and an increased risk of bleeding. In addition to anti-platelet autoantibodies, CD8⁺ T cells have been implicated as a mechanism of platelet destruction. The current evidence for the existence of platelet-specific CD8⁺ T cells in ITP is inconclusive. The purpose of this review is to summarize the studies that investigated CD8⁺ T cells in ITP and to review the methods that have been used to detect autoreactive CD8⁺ T cells in other autoimmune diseases.

Comparison of house dust mite sensitization profiles in allergic adults from Canada, Europe, South Africa and USA

BACKGROUND

Sensitization to house dust mite (HDM) is a leading cause of allergic rhinitis and asthma. Despite more than 30 HDM-derived allergens having been identified to date, specific therapeutic approaches do not yet take into account the local sensitization profiles of patients. This study aimed to identify patterns of HDM sensitization in HDM-allergic adults living in distinct geographic areas, to inform the development of targeted diagnostic and therapeutic tools.

METHODS

Serum samples from 685 HDM-allergic subjects from Canada, Europe, South Africa, and the USA were tested for levels of IgE specific for 17 micro-arrayed HDM allergens by ImmunoCAP Immuno Solid-phase Allergen Chip (ISAC) technology.

RESULTS

The results confirmed significant geographical variability in sensitization patterns and levels of IgE. In all areas, the major sensitizers were the group 1 and group 2 allergens and Der p 23. Der p 23 was a frequent sensitizer: 64% of the subjects had IgE specific for Der p 23, and 2.3% were monosensitized to it. In South Africa, Der p 23 was the dominant HDM allergen (86% prevalence) and Der p 7 achieved major allergen status (56%). IgE sensitization to HDM was influenced by asthmatic status, levels of allergen exposure, age, race-ethnicity and smoking status, but not by BMI.

CONCLUSION

Sensitization profiles to HDM allergens differ considerably among distinct geographic areas, with Der p 7 and Der p 23 being major sensitizers in South Africa. Such heterogeneity should be taken into account in the diagnosis and treatment of HDM-allergic patients.

Nasal allergen challenge and environmental exposure chamber challenge: A randomized trial comparing clinical and biological responses to cat allergen

BACKGROUND

The direct-instillation nasal allergen challenge (NAC) and the environmental exposure chamber (EEC) are 2 methods of conducting controlled allergen provocations. The clinical and biological comparability of these methods has not been thoroughly investigated.

OBJECTIVE

We sought to compare clinical and immunologic responses to cat allergen in NAC versus EEC.

METHODS

Twenty-four participants were randomized to receive either NAC followed by a 2-day challenge in an EEC or a 2-day challenge in an EEC followed by NAC. Challenges were separated by 28-day washout periods. We measured total nasal symptom scores, peak nasal inspiratory flow, nasal (0-8 hours) and serum cytokines, serum antibodies, peripheral blood antigen-specific T lymphocytes, and gene expression in nasal scrapings. The primary outcome was the total nasal symptom score area under the curve for the first 3 hours after allergen exposure in NAC or after initiation of exposure in EEC.

RESULTS

Both challenges increased IL-5 and IL-13 in nasal fluids and serum and resulted in altered nasal cell expression of gene modules related to mucosal biology and transcriptional regulation. Changes in gene modules, more so than cytokine measurements, showed significant associations with total nasal symptom score and peak nasal inspiratory flow. Overall, EEC exposure generated larger responses and more early terminations compared with NAC. Although the 2 challenges did not correlate in symptom magnitude or temporality, striking correlations were observed in cytokine levels.

CONCLUSIONS

Although clinical outcomes of NAC and EEC were temporally different and nonequivalent in magnitude, immunologic responses were similar. Selection of a particular allergen challenge method should depend on considerations of study objectives and cost.

Mammalian target of rapamycin is activated in the kidneys of patients with scleroderma renal crisis

Objectives:

Scleroderma renal crisis is a rare but serious complication affecting 2%–15% of patients with systemic sclerosis. Despite treatment with angiotensin-converting enzyme inhibitors, outcomes for scleroderma renal crisis patients are still poor. The cellular signaling mechanisms in scleroderma renal crisis are not yet known. Mammalian target of rapamycin, comprised of the subunits mTORC1 and mTORC2, has been shown to be activated in vascular lesions of renal transplant patients with anti-phospholipid antibody syndrome. Given the similarities between the pathophysiology of scleroderma renal crisis and anti-phospholipid antibody syndrome, we hypothesized that the mammalian target of rapamycin pathway would also be activated in the renal vasculature of patients with scleroderma renal crisis.

Methods:

We retrospectively analyzed renal biopsies of five patients with scleroderma renal crisis in the Canadian Scleroderma Research Group cohort. Immunostaining was performed using anti-P-S6RP antibodies to evaluate the phosphorylation of mTORC1, and anti-Rictor and anti-S473 to determine activation of mTORC2.

Results:

Four of the five patients showed mTORC1 activation in arteriolar endothelial cells, and three of the five patients showed mTORC1 activation in the arterial endothelial cells. Two of four samples showed Rictor expression in the arteriolar and arterial endothelial cells, showing mTORC2 activation. There was no expression of mTORC1 or mTORC2 in samples from two healthy controls.

Conclusion:

We demonstrate that both mTORC1 and mTORC2 are activated in renal biopsies with typical histologic features of scleroderma renal crisis. Dual mammalian target of rapamycin inhibitors are currently available and in development. These findings could inform further research into novel treatment targets for scleroderma renal crisis.

Modulation of CRTh2 expression on allergen-specific T cells following peptide immunotherapy

Background

Allergen immunotherapy using synthetic peptide T‐cell epitopes (Cat‐PAD) from the major cat allergen Fel d 1 has been shown, in allergen exposure studies, to significantly reduce symptoms of allergic rhinoconjunctivitis in cat‐allergic subjects. However, the immunological mechanisms underlying clinical benefit remain only partially understood. Since previous studies of whole allergen immunotherapy demonstrated a reduction in the frequency of allergen‐specific (MHC II tetramer⁺) CD4⁺ T cells expressing the chemokine receptor CRTh2, we assessed the impact of Cat‐PAD on the frequency and functional phenotype of Fel d 1‐specific CD4⁺ T cells.

Methods

Using before and after treatment samples from subjects enrolled in a randomized, double‐blind, placebo‐controlled trial of Cat‐PAD, we employed Fel d 1 MHC II tetramers and flow cytometry to analyze the expression of chemokine receptors CCR3, CCR4, CCR5, CXCR3, and CRTh2, together with markers of memory phenotype (CD27 and CCR7) on Fel d 1‐specific CD4⁺ T cells.

Results

No statistically significant change in the frequency of Fel d 1‐specific CD4⁺ T cells, nor in their expression of chemokine receptors or memory phenotype, was observed. However, a significant reduction in cell surface expression of CRTh2 was observed between the placebo and active groups (P = 0.047).

Conclusions

Peptide immunotherapy with Cat‐PAD does not significantly alter the frequency or phenotype of Fel d 1‐CD4⁺ T cells, but may decrease their expression of CRTh2.

Cellular immune responses to platelet factor 4 and heparin complexes in patients with heparin-induced thrombocytopenia

Essentials The immunogenesis of Heparin-induced thrombocytopenia (HIT) is not well understood. Immunization to platelet factor 4 (PF4)-heparin occurs early in life, before any heparin exposure. PF4 and PF4-heparin complexes induce the proliferation of CD14+ cells. Reduced levels of regulatory cytokines contribute to immune dysregulation in HIT.

SUMMARY

Background Heparin-induced thrombocytopenia (HIT) is an adverse reaction to heparin characterized by thrombocytopenia and thrombotic complications. HIT is caused by pathogenic antibodies that bind to complexes of platelet factor 4 (PF4) and heparin, leading to platelet activation and inducing a hypercoagulable state. Previous studies have shown immunity to PF4-heparin complexes occurs early in life, even before heparin exposure; however, the immunogenesis of HIT is not well characterized. Objectives To investigate cellular proliferation in response to PF4-heparin complexes in patients with HIT. Patients/Methods Peripheral blood mononuclear cells (PBMCs) from healthy controls (n = 30), postoperative cardiac surgery patients who had undergone cardiopulmonary bypass (CPB) (n = 17) and patients with confirmed HIT (n = 41) were cultured with PF4 and PF4-heparin complexes. Cellular proliferation was assessed by [3 H]thymidine uptake and 5-ethynyl-2'-deoxyuridine detection. Results and Conclusions PBMCs proliferated in the presence of PF4, and this was enhanced by the addition of heparin in all study groups. CPB and HIT patients showed significantly greater proliferative responses than healthy controls. PBMC proliferation was antigen-specific, depended on the presence of platelets, and only CD14+ cells were identified as proliferating cells. Culture supernatants were tested for the levels of regulatory cytokines, and both CPB and HIT patients produced significantly lower levels of interleukin-10 and transforming growth factor-β1 than healthy controls. These findings further demonstrate cellular immune sensitization to PF4-heparin complexes occurs before heparin exposure, and suggests immune dysregulation can contribute to HIT.

Induction of bystander tolerance and immune deviation after Fel d 1 peptide immunotherapy

BACKGROUND

Treatment of patients with cat allergy with peptides derived from Fel d 1 (the major cat allergen) ameliorated symptoms of cat allergy in phase 2 clinical trials.

OBJECTIVE

We sought to demonstrate that the tolerance induced by Fel d 1 peptide immunotherapy can be exploited to reduce allergic responses to a second allergen, ovalbumin (OVA), in mice sensitized dually to OVA and Fel d 1.

METHODS

Induction of tolerance to OVA was achieved through simultaneous exposure to both allergens after peptide treatment. Functional tolerance to each allergen was assessed in a model of allergic airways disease in which treated mice were protected from eosinophilia, goblet cell hyperplasia, and T_H2 cell infiltration.

RESULTS

Suppression of allergic responses to cat allergen challenge was associated with significant increases in numbers of CD4⁺CD25⁺Foxp3⁺ T cells, IL-10⁺ cells, and CD19⁺IL-10⁺ B cells, whereas the response to OVA was associated with a marked reduction in numbers of T_H2 cytokine-secreting T cells and less prominent changes in outcomes associated with immune regulation.

CONCLUSIONS

These observations suggest that immune tolerance induced by peptide immunotherapy can be used experimentally to treat an allergic response to another allergen and that the molecular mechanisms underlying induction of tolerance to a treatment-specific allergen and a bystander allergen might be different.

The Allergic Rhinitis Clinical Investigator Collaborative (AR-CIC): verification of nasal allergen challenge procedures in a study utilizing an investigational immunotherapy for cat allergy

Background

The Allergic Rhinitis Clinical Investigator Collaborative (AR-CIC) is a network of experienced Allergic Rhinitis (AR) researchers developing better research tools based on the nasal allergen challenge (NAC). A key objective of such is the ability to detect efficacy in a small population. AR-CIC sought to test its NAC protocol as a secondary objective in two small mechanistic research trials of a novel form of immunotherapy [Cat Peptide Antigen Desensitisation (Cat-PAD)] for which efficacy had previously been demonstrated. The primary objective (not presented here) was to identify potential biomarkers of efficacy for peptide immunotherapy, and this provided an ideal opportunity to corroborate the NAC protocol. We aim to clinically validate the AR-CIC NAC methodology in a pooled analysis of secondary endpoints measured in two open label mechanistic studies of cat allergic participants treated with Cat-PAD.

Methods

Cat allergic AR sufferers with ongoing cat exposure were included. Participants had to demonstrate a total nasal symptom score (TNSS) of at least 8 (max 12) and/or achieve a reduction in peak nasal inspiratory flow (PNIF) of ≥ 50% during a screening titrated NAC. Eligible participants then underwent a baseline NAC visit with the allergen dose that produced a positive challenge at screening, followed by four monthly injections of 6 nmol Cat-PAD. A follow up NAC visit documented changes in nasal response 1 month following the completion of treatment.

Results

Nineteen subjects completed the study protocol in the two studies combined. Four injections of Cat-PAD resulted in a significant reduction in TNSS responses generated via NAC following allergen challenge (15 min p < 0.05, 30 min p < 0.05, 1 h p < 0.01, 2 h p < 0.05). There was modest correlation between symptom scores and PNIF measurements.

Conclusions

This study supports the validity of the AR-CIC’s optimised NAC protocol for conducting research of the potential efficacy of novel therapeutics in multi-centre studies.

Trial registration Both studies reported herein were registered clinicaltrials.gov (NCT01383590 and NCT01383603)

Perspectives in allergen immunotherapy: 2017 and beyond

The Future of the Allergists and Specific Immunotherapy (FASIT) workshop provides a regular platform for global experts from academia, allergy clinics, regulatory authorities and industry to review developments in the field of allergen immunotherapy (AIT). The most recent meeting, held in February 2017, had two main themes: advances in AIT and hot topics in AIT from the regulatory point of view. The first theme covered opportunities for personalized AIT, advances in adjuvants and delivery systems, and the development of new molecules and future vaccines for AIT. Key topics in the second part of the meeting were the effects of the enactment of European Directive 2001/83 on the availability of allergens for therapy and diagnosis across the EU, the challenges of conducting Phase 3 studies in the field, the future role of allergen exposure chambers in AIT studies and specific considerations in performing AIT studies in the paediatric population. Finally, the group highlighted the forthcoming EAACI guidelines and their particular importance for the standardization of practice in the treatment of allergies. This review presents a comprehensive insight into those panel discussions and highlights unmet needs and also possible solutions to them for the future.

Novel approaches and perspectives in allergen immunotherapy

In this review, we report on relevant current topics in allergen immunotherapy (AIT) which were broadly discussed during the first Aarhus Immunotherapy Symposium (Aarhus, Denmark) in December 2015 by leading clinicians, scientists and industry representatives in the field. The aim of this symposium was to highlight AIT-related aspects of public health, clinical efficacy evaluation, mechanisms, development of new biomarkers and an overview of novel therapeutic approaches. Allergy is a public health issue of high socioeconomic relevance, and development of evidence-based action plans to address allergy as a public health issue ought to be on national and regional agendas. The underlying mechanisms are in the focus of current research that lays the ground for innovative therapies. Standardization and harmonization of clinical endpoints in AIT trials as well as current knowledge about potential biomarkers have substantiated proof of effectiveness of this disease-modifying therapeutic option. Novel treatments such as peptide immunotherapy, intralymphatic immunotherapy and use of recombinant allergens herald a new age in which AIT may address treatment of allergy as a public health issue by reaching a large fraction of patients.

Allergen exposure chambers: harmonizing current concepts and projecting the needs for the future - an EAACI Position Paper

BACKGROUND

Allergen exposure chambers (AECs) are clinical facilities allowing for controlled exposure of subjects to allergens in an enclosed environment. AECs have contributed towards characterizing the pathophysiology of respiratory allergic diseases and the pharmacological properties of new therapies. In addition, they are complementary to and offer some advantages over traditional multicentre field trials for evaluation of novel therapeutics. To date, AEC studies conducted have been monocentric and have followed protocols unique to each centre. Because there are technical differences among AECs, it may be necessary to define parameters to standardize the AECs so that studies may be extrapolated for driving basic immunological research and for marketing authorization purposes by regulatory authorities.

METHODS

For this task force initiative of the European Academy of Allergy and Clinical Immunology (EAACI), experts from academia and regulatory agencies met with chamber operators to list technical, clinical and regulatory unmet needs as well as the prerequisites for clinical validation.

RESULTS

The latter covered the validation process, standardization of challenges and outcomes, intra- and interchamber variability and reproducibility, in addition to comparability with field trials and specifics of paediatric trials and regulatory issues.

CONCLUSION

This EAACI Position Paper aims to harmonize current concepts in AECs and to project unmet needs with the intent to enhance progress towards use of these facilities in determining safety and efficacy of new therapeutics in the future.

An Update on Lymphocyte Subtypes in Asthma and Airway Disease

Inflammation is a hallmark of many airway diseases. Improved understanding of the cellular and molecular mechanisms of airway disease will facilitate the transition in our understanding from phenotypes to endotypes, thereby improving our ability to target treatments based on pathophysiologic characteristics. For example, allergic asthma has long been considered to be driven by an allergen-specific T helper 2 response. However, clinical and mechanistic studies have begun to shed light on the role of other cell subsets in the pathogenesis and regulation of lung inflammation. In this review, we discuss the importance of different lymphocyte subsets to asthma and other airway diseases, while highlighting the growing evidence that asthma is a syndrome that incorporates many immune phenotypes.

Prediction of clinical peanut allergy status among children in Hamilton, Ontario using chart review data collected during 2012-2015

Background

Peanut sensitization does not necessarily indicate clinical peanut allergy, and uncertainty as to whether or not there is true peanut allergy can lead to increased anxiety and decreased quality of life for patients and their families. The gold standard for diagnosing clinical peanut allergy is the oral food challenge, but this method is time-consuming and can cause severe allergic reactions. It would therefore be beneficial to develop a tool for predicting clinical peanut allergy in peanut-sensitized individuals whose peanut allergy status is unknown so as to better determine who requires an oral food challenge for diagnosis.

Methods

Two separate studies were conducted. In Study 1, we recruited 100 participants from the allergy clinic at McMaster University and community allergy outpatient clinics in the greater Hamilton area. We examined 18 different variables from participants and used univariate and multivariable logistic regression analysis to determine how well these variables, singly and in combination, were able to predict clinical peanut allergy status. In Study 2, we conducted a retrospective chart review of a second cohort of 194 participants to investigate the reproducibility of our findings. This was a matched case–control study where 97 peanut-allergic participants were gender- and age-matched to 97 non-allergic control participants.

Results

Peanut skin prick test wheal size was the best predictor of clinical peanut allergy in both study cohorts. For every 1 mm increase in wheal size, the odds ratio of an individual having clinical peanut allergy was 2.36 in our first cohort and 4.85 in our second cohort. No other variable approached the predictive power of wheal size.

Conclusions

Peanut skin prick test wheal size is a robust predictor of clinical peanut reactivity. The findings of this study may be useful in guiding clinician decision-making regarding peanut allergy diagnostics.

T regulatory cell phenotypes in peripheral blood and bronchoalveolar lavage from non-asthmatic and asthmatic subjects

BACKGROUND

An unresolved issue in T regulatory cells' cell biology is the lack of consensus on phenotypic markers that accurately define the natural Treg (nTreg) population.

OBJECTIVES

To examine nTreg frequency and functional capacity in healthy controls and their frequency in asthmatic subjects using three different phenotypic strategies. We hypothesized that phenotypically different nTreg are quantitatively and functionally different.

METHODS

Thirty-four healthy, non-asthmatic and 17 asthmatic subjects were studied. Three nTreg phenotypes were defined as follows: nTreg1 (CD4(+) CD25(+) Foxp3(+) ), nTreg2 (CD4(+) CD25(+) CD127(low) Foxp3(+) ), and nTreg3 (CD4(+) CD25(high) Foxp3(+) ). The flow cytometric determination of nTreg frequency in peripheral blood (PB) and bronchoalveolar lavage (BAL) was performed using fluorescently labelled antibodies. Peripheral blood nTreg functional capacity was assessed using a CFSE-based suppression assay.

RESULTS

There was a significantly lower frequency of PB nTreg3 compared to nTreg2 and nTreg1 (P < 0.05). Both nTreg2 and nTreg3 had a significantly greater suppressive capacity than nTreg1 at T responder (Tresp) to nTreg ratios of 16 : 1 up to 1 : 1 (P < 0.01). Asthmatics exhibited a significantly lower PB nTreg3 and nTreg1 frequency than healthy controls (P < 0.05). There were no differences between healthy controls and asthmatic subjects when comparing BAL nTreg frequency.

CONCLUSIONS AND CLINICAL RELEVANCE

Phenotypically different nTreg subsets are quantitatively and functionally different and are variably observed in asthma. The CD4(+) CD25(high) Foxp3(+) phenotype was the least frequent, but demonstrated the greatest suppression, and was significantly lower in PB of asthmatic subjects. Consequently, it is imperative that nTreg phenotypes be clearly defined and that the interpretation of their frequency and function be phenotype specific.

Allergen immunotherapy on the way to product-based evaluation-a WAO statement

Allergen immunotherapy (AIT) is widely used in clinical practice for patients with moderate to severe allergic rhinitis due to inhalant allergens and may be delivered via subcutaneous (SCIT) and sublingual routes (SLIT). However, the quality of evidence for individual AIT products is very heterogeneous, and extensions of overall conclusions ("class effects") on the efficacy and disease-modifying effects to all AIT products are unjustified. In contrast, each product needs to be evaluated individually, based on available study results, to justify efficacy and specific claims on sustained and disease modifying effects per allergen and targeted patient group (children vs. adults, allergic rhinitis vs. asthma). WAO intends to support the current development to evidence-based AIT, which ultimately will lead to a more efficacious treatment of allergic patients and the appropriate recognition of AIT.

Comprehensive metabolomics identifies the alarmin uric acid as a critical signal for the induction of peanut allergy

BACKGROUND

Food allergy, in particular peanut allergy, is a growing concern in Western countries. The prevalence of allergy to peanut, which currently stands at 1.4%, nearly tripled between 1997 and 2008. Allergic sensitization is a particularly difficult process to study as it is clinically silent. We sought to identify key pathways and mediators critically involved in the induction of allergic sensitization to peanut.

METHODS

Comprehensive metabolomics analysis with liquid chromatography-mass spectrometry was used to detect metabolite changes in mice (C57BL/6) undergoing sensitization. Loss-of-function and gain-of-function studies were performed in mice subjected to two models of peanut sensitization and anaphylaxis that involved either oral or epicutaneous sensitization. Flow cytometric analyses on dendritic cells (DCs) in vitro and in vivo were used to investigate the mechanisms of immune activation.

RESULTS

Elevated levels of uric acid (UA) were detected in mice undergoing sensitization as well as in peanut-allergic children who were not challenged with peanut. In mice, the depletion of UA during sensitization prevented the development of peanut-specific immunoglobulins IgE and IgG1 as well as anaphylaxis while exogenous delivery of UA crystals (monosodium urate, MSU) restored the allergic phenotype. Monosodium urate enhanced CD86 and OX40L expression on DCs, independent of Toll-like receptors 2 and 4, the NLRP3 inflammasome, and IL-1β, via a PI3K signaling pathway.

CONCLUSION

Overproduction of the UA alarmin in the local microenvironment plays a critical role in the induction of peanut-allergic sensitization, likely due to its ability to activate DCs. These finding suggest that cellular damage or tissue injury may be an essential requisite for the development of allergic sensitization to foods.

T cell-mediated induction of thymic stromal lymphopoietin in differentiated human primary bronchial epithelial cells

BACKGROUND

Inhaled peptide challenge has been shown to induce T cell-mediated, isolated late asthmatic reaction (LAR), characterized by recruitment of CD4(+) T cells and increased levels of thymus and activation-regulated chemokine (TARC; CCL17). Epithelial-derived thymic stromal lymphopoietin (TSLP) has been shown to modulate dendritic cell function to promote TH 2 responses via CCL17 production.

OBJECTIVES

To elucidate the mechanisms involved in allergen-specific T cell-induced LAR and recruitment of CD4(+) T cells by examining the effects of T cell-derived factors on the induction of TSLP in primary bronchial epithelial cells (PBEC).

METHODS

PBEC grown at air-liquid interface from healthy individuals and patients with asthma were stimulated with double-stranded RNA (dsRNA) or supernatants from activated allergen-specific T cells. TSLP was measured in PBEC culture supernatants. Neutralizing antibodies and signalling inhibitors were used to examine the mechanisms responsible for the induction of epithelial-derived TSLP. The functional activity of PBEC-derived TSLP was measured using a bioassay involving the induction of CCL17 production from monocyte-derived dendritic cells (moDC).

RESULTS

Both dsRNA and allergen-specific T cells induced enhanced TSLP secretion from asthmatic PBEC compared to healthy PBEC. Activated PBEC culture supernatant induced TSLP-dependent CCL17 production from moDC in a manner related to clinical asthmatic status. IL-1β, IL-6, and CXCL8, rather than TH 2 cytokines (IL-4/5/13), appeared to be the principle mediators of allergen-specific T cell-dependent induction of epithelial-derived TSLP, which was regulated by the MEK, MAPK, and NFκB pathways.

CONCLUSION AND CLINICAL RELEVANCE

Our data reveal a novel effect of allergen-specific T cells as a positive regulator of TSLP production by epithelial cells, suggesting T cell-airway epithelium interactions that may lead to maintenance and amplification of allergic inflammation. TSLP is currently a candidate for therapeutic intervention in asthma, but the factors that drive TSLP expression (T cell-derived factors) may be equally relevant in the treatment of allergic inflammation.

Peptide Immunotherapy; short but long lasting?

Allergen immunotherapy (AIT) with whole allergens or allergen extracts has been in use for more than one hundred years. It is clinically efficacious and disease-modifying. However, AIT is also associated with a significant adverse events profile, including the potential to cause severe, systemic allergic reactions. One alternative to traditional whole-antigen AIT is peptide immunotherapy, which uses small synthetic peptide immunoregulatory epitopes (SPIRE) representing T cell epitopes from the allergen of interest. Peptide immunotherapy is being developed for the treatment of allergic and autoimmune diseases where pathogenesis is T cell-dependent. Short, soluble, monomeric peptide fragments avoid the problem of IgE-mediated adverse events (since the peptides will not cross-link allergen-specific IgE on the surface of effector cells such as mast cells and basophils). However, such peptides retain the capability to induce T cell tolerance and immunoregulation. In early clinical trials, efficacy has been demonstrated months to years after the cessation of a short course of treatment, supporting the conclusion that this approach is disease-modifying, changing the natural history of the disease. The improved safety profile of short peptides allows for larger molar-equivalent doses to be administered in shorter time frames than AIT; treatment can be completed in as few as four intradermal injections, while efficacy persists for two years or more.

OX40L blockade and allergen-induced airway responses in subjects with mild asthma

Background

The OX40/OX40L interaction contributes to an optimal T cell response following allergic stimuli and plays an important role in the maintenance and reactivation of memory T effector cells.

Objective

We tested whether treatment with an anti-OX40L monoclonal antibody (MAb) would inhibit allergen-induced responses in subjects with asthma.

Methods

Twenty-eight mild, atopic asthmatic subjects were recruited for a double-blind, randomized, placebo-controlled, parallel-group trial (ClinicalTrials.gov identifier NCT00983658) to compare blockade of OX40L using a humanized anti-OX40L MAb to placebo-administered intravenously in 4 doses over 3 months. Allergen inhalation challenges were carried out 56 and 113 days after the first dose of study drug. The primary outcome variable was the late-phase asthmatic response. Other outcomes included the early-phase asthmatic response, airway hyperresponsiveness, serum IgE levels, blood and sputum eosinophils, safety and tolerability.

Results

Treatment with anti-OX40L MAb did not attenuate the early- or late-phase asthmatic responses at days 56 or 113 compared with placebo. In the anti-OX40L MAb treatment group, total IgE was reduced 17% from pre-dosing levels, and sputum eosinophils decreased 75% by day 113 (both P = 0.04). There was no effect of anti-OX40L MAb on airway hyperresponsiveness or blood eosinophils. The frequency of AEs was similar in both groups.

Conclusion and Clinical Relevance

Pharmacological activity of anti-OX40L MAb was observed by decreases in serum total IgE and airway eosinophils at 16 weeks post-dosing, but there was no effect on allergen-induced airway responses. It is possible that the treatment duration or dose of antibody was insufficient to impact the airway responses.

Cytokine responses of peripheral blood mononuclear cells to allergen do not identify asthma or asthma phenotypes

BACKGROUND

Asthmatic patients are often differentiated based on their atopic status (atopic or nonatopic) and type of bronchitis (eosinophilic, neutrophilic, both, or neither). There is evidence supporting a central role for the T cell in asthma, but the role of allergen-induced T cell cytokines in driving disease in different asthma phenotypes remains unclear.

OBJECTIVE

To investigate the hypothesis that peripheral blood mononuclear cells (PBMCs) from asthma patients with different phenotypes would react characteristically to a panel of common aeroallergens.

METHODS

We incubated PBMCs from 41 asthma patients and 8 healthy controls with allergen and assessed PBMC proliferation by (3) H-thymidine incorporation and the production of the cytokines IL-5, IL-17A, IL-23, IL-10, and IFN-γ by ELISA.

RESULTS

No differences in PBMC proliferation or cytokine production were found in patients with asthma, compared with healthy controls, or between patients with different asthma phenotypes.

CONCLUSIONS AND CLINICAL RELEVANCE

Peripheral blood mononuclear cell cytokine responses to allergen are not able to assist in the discrimination between disease state, atopic status, or type of bronchitis in asthma.

Peptide-based immunotherapy: a novel strategy for allergic disease

The T-cell component of the antigen-specific immune response is the target of various novel interventions to modify chronic immunologic disorders, such as allergic diseases. Recent clinical trials have evaluated the safety and efficacy of therapeutic vaccines consisting of short, synthetic, allergen-derived peptides, corresponding to T-cell epitopes from the eliciting antigen. The main advantage of such an approach is the reduction in systemic, immunoglobulin E-mediated adverse events compared with existing whole allergen immunotherapy, often referred to as 'allergy shots'. T-cell peptide epitopes, although capable of inducing immunologic tolerance, are short linear structures that have reduced ability to cross-link mast cell- and basophil-bound immunoglobulin E. The precise mechanism of tolerance induction remains incompletely defined. However, recent data indicate that peptide therapy induces/expands a population of antigen-specific regulatory T-cells. A novel form of treatment combining efficacy with a substantially decreased occurrence of adverse events is likely to have a major impact on the management and prevalence of allergic diseases. Furthermore, the principles of epitope-specific therapy hold promise for the development of therapeutic vaccines for the treatment of autoimmune diseases.

Fel d 1-derived peptide antigen desensitization shows a persistent treatment effect 1 year after the start of dosing: a randomized, placebo-controlled study

BACKGROUND

Allergic rhinoconjunctivitis is an increasingly common source of morbidity, with sensitivity to cats accounting for 10% to 15% of disease burden. Allergy to cats is also a major risk factor for the development of asthma.

OBJECTIVES

We sought to probe the persistence of the treatment effect of a novel F el d 1-derived peptide antigen desensitization (Cat-PAD) 1 year after the start of treatment in subjects with cat allergy-induced rhinoconjunctivitis after standardized allergen challenge.

METHODS

In a randomized, double-blind, placebo-controlled, parallel-group clinical trial, subjects attended an environmental exposure chamber in which they were exposed to cat allergen before and after treatment with 2 different regimens of Cat-PAD over a 3-month period. Clinical efficacy was assessed as a change in total rhinoconjunctivitis symptom scores 18 to 22 weeks and 50 to 54 weeks after the start of treatment.

RESULTS

Treatment with Cat-PAD showed greater efficacy with 4 administrations of a 6-nmol dose 4 weeks apart than with 8 administrations of a 3-nmol dose 2 weeks apart. The treatment effect of 6 nmol persisted 1 year after the start of treatment and was significantly different from that of 3 nmol (P = .0342) and placebo (P = .0104). The treatment effect was apparent on both nasal and ocular symptoms at 1 year.

CONCLUSIONS

A short course of Cat-PAD improves the ocular and nasal components of rhinoconjunctivitis symptoms in subjects with cat allergy, with the treatment effect persisting 1 year after the start of treatment.

Functional rather than immunoreactive levels of IgG4 correlate closely with clinical response to grass pollen immunotherapy

BACKGROUND

Induction of allergen-specific IgG(4) antibodies is the most consistent immunological finding in immunotherapy trials. However, quantitative assessments of IgG(4) antibodies have not proven beneficial in evaluating clinical changes during or after immunotherapy. In the current study, we investigated the relationship between clinical outcome and allergen-specific IgG(4) titres or functional antibody responses following immunotherapy. We hypothesized that functional assays of serum IgG-associated inhibitory activity such as inhibition of IgE-allergen interactions (IgE-blocking factor) and inhibition of CD23-dependent IgE-facilitated allergen binding (IgE-FAB) correlate more closely with clinical outcome and may be biomarkers of clinical response.

METHODS

In an 8-month dose-response randomized double-blind placebo-controlled study, 221 polysensitized subjects with severe seasonal rhinitis received Alutard SQ, Phleum pratense 100,000 SQ-U, 10,000 SQ-U or placebo injections. Serum specimens were collected before treatment, after up-dosing, during the peak season and at the end of the study. Allergen-specific IgG(4) titres and IgG-associated inhibitory activity were evaluated.

RESULTS

A time- and dose-dependent increase in serum inhibitory activity for both the IgE-blocking factor and IgE-FAB was observed, which paralleled increases in grass pollen-specific IgG(4) antibodies. A modest but significant inverse relationship was demonstrated between postimmunotherapy serum inhibitory activity and combined symptom-rescue medication scores (IgE-FAB: r = -0.25, P = 0.0002; IgE-blocking factor: r = -0.28, P < 0.0001), whereas this was not observed for immunoreactive IgG(4) levels (r = -0.11, P = 0.12).

CONCLUSIONS

Functional assays of inhibitory IgG(4) and IgE-blocking factor may be more useful surrogates of clinical response than IgG(4). Whether these antibody effects may serve as predictive biomarkers of clinical efficacy in individual patients requires further investigation.

Peptide and recombinant immunotherapy

Because of the need to standardize allergen immunotherapy and the desire to reduce allergic adverse events during therapy, a transition to recombinant/synthetic hypoallergenic approaches is inevitable. Evidence supports the notion that effective therapy can be delivered using a limited panel of allergens or even epitopes, weakening the argument that all allergens must be present for optimal efficacy. Moreover, standardized products will allow direct comparisons between studies and, for the first time, immunotherapy studies will be truly blinded, allowing an accurate assessment of the actual treatment effect that can be achieved with this form of intervention.

Immunotherapy with peptides

Specific allergen immunotherapy is clinically effective and disease modifying. It has a duration of effect that exceeds the treatment period and prevents both the progression of allergic rhinitis to asthma and the acquisition of new allergic sensitizations. However, immunotherapy is associated with a high frequency of adverse events related to the allergenicity of vaccines. Allergenicity is conferred by the presence of intact B-cell epitopes that crosslink allergen-specific IgE on effector cells. The use of linear peptide sequences representing fragments of the native allergen is one approach to reduce allergenicity. Preclinical models of peptide immunotherapy have demonstrated efficacy in both autoimmunity and allergy. Translation of this technology into the clinic has gained momentum in recent years based on encouraging results from early clinical trials. To date, efforts have focused on two major allergens, but vaccines to a broader range of molecules are currently in clinical development. Mechanistically, peptide immunotherapy appears to work through the induction of adaptive, allergen-specific regulatory T cells that secrete the immunoregulatory cytokine IL-10. There is also evidence that peptide immunotherapy targeting allergen-specific T cells can indirectly modulate allergen-specific B-cell responses. Peptide immunotherapy may provide a safe and efficacious alternative to conventional subcutaneous and/or sublingual approaches using native allergen preparations.