This review examines whether allergen immunotherapy (AIT) for grass pollen allergy should expand beyond the recent trend towards a mono-species approach based on Phleum pratense. It explores whether multi-species formulations better reflect natural exposure and could improve clinical outcomes. Research from aerobiology and immunology shows that grass pollen exposure involves diverse species with distinct flowering periods, influenced by climate and geography. Molecular analyses reveal species-specific allergen profiles, including unique peptides and variations in major allergens such as Group 1 and 5. Patient data confirm symptom variability across the season. In-vitro studies have observed limits to the cross-reactivity of T-cell epitopes, and comparative clinical studies suggest benefits for multi-species treatment options. Evidence indicates that mono-species extracts alone do not represent the full allergenic spectrum of grass pollen. Broad-spectrum AIT formulations incorporating multiple grass species provide a more comprehensive repertoire of allergens and epitopes, potentially enhancing immunogenicity and therapeutic benefit. This supports the hypothesis that diversity does not equate to dilution in broad-spectrum formulations. The approach aligns with patient symptom patterns and may improve efficacy and asthma prevention. Future research could further refine species selection and leverage molecular diversity to optimize treatment strategies.

BackgroundVenom immunotherapy (VIT) with aqueous venom extracts is a standard treatment for severe insect venom allergies. In other fields of allergen immunotherapy (AIT), depot adjuvants have been used for decades, with benefits for both safety and efficacy. Biodegradable microcrystalline tyrosine (MCT), is well-established in AIT, and has proven both safe and effective through sustained release and adjuvancy. The objective of the current study was to evaluate MCT as a depot-forming agent in VIT using a murine model of bee venom allergy.Materials and methodsMice were sensitised with bee venom extract and then received subcutaneous immunotherapy (SCIT) with 10, 50, or 100 µg aqueous venom extracts or venom formulated with MCT or aluminium hydroxide (alum) as depot-forming agents. Systemic reactions upon VIT and challenge were assessed by measuring body temperature, while antigen-specific IgE and IgG responses were analysed by ELISA. Mast cell degranulation was evaluated by serum MCPT-1 levels.ResultsVIT with MCT significantly improved survival, reduced body temperature changes, and promoted robust IgG1 and IgG2b responses. While antibody responses were comparable between MCT and alum at higher VIT doses (50 and 100 µg), MCT also induced significant IgG responses at lower doses (10 µg), indicating enhanced sensitivity of the immune response to MCT. MCT-treated mice further exhibited reduced mast-cell degranulation compared to untreated controls, consistent with a reduced risk of anaphylaxis.ConclusionVIT with bee venom extract and MCT enabled safe and effective VIT by promoting protective IgG responses and reducing systemic reactions. These findings further support the evaluation of MCT as a complement to aqueous allergen extracts in VIT for human use.

The transitioning of named patient products (NPPs) of therapy allergens is regulated under the German therapy allergen ordinance (TAO) since 2008. The establishment of a sound dose–response relationship constitutes a pivotal aspect in clinical development programs of drugs in general. Up to now, there are only few comprehensive studies dedicated to the determination of a dose–response relationship in allergen immunotherapy (AIT) because of various challenges. Among these aggravating factors are high placebo effects, variability of trial endpoints and especially for native allergens a narrow therapeutic window and safety profile. The phase II trials of the modified allergen tyrosine associated—monophosphoryl lipid A (MATA MPL) platform for birch and grasses established convincing and significant dose–response relationships decisive for AIT product optimization. The significant dose–response relationship for birch and grass allergoids reached an efficacy plateau and allowed the definition of critical milestones in drug development such as the median effective dose (ED50) for the MATA MPL platform combining modified allergens (allergoids) with microcrystalline tyrosine (MCT) and MPL in an adjuvant system. This marked a pivotal milestone in AIT drug development allowing the definition of the “optimal dose” (optimal risk–benefit ratio) to be taken forward to phase III trial. The MATA MPL platform is characterized by a scientifically sound dose–response relationship across allergens which underlines the pivotal role of a well-defined optimal dose as a success factor for phase III.

BACKGROUND:Regulatory authorities recommend a combination of symptom and medication scores during the grass pollen season as a primary endpoint for Phase III allergen immunotherapy (AIT) trials targeting allergic rhinoconjunctivitis. However, many composite primary endpoint scales exist; none are validated, nor do they have a well-justified minimal clinically important difference (MCID). METHODS:Direct patient feedback from 1071 grass-allergic patients was obtained to determine the minimally relevant improvement in allergic symptoms and translated into an MCID for the EAACI recommended CSMS0-6. Additionally, a clinically relevant threshold for the validated Rhinitis Quality of Life Questionnaire (RQLQ(S)) was determined from studies of registered SLIT products and subsequently used as an anchor to derive the MCID for CSMS0-6 using the data of a Phase III clinical trial with PQ Grass 27,600 SU (RESONATE). RESULTS:69% of grass-allergic patients were satisfied with a 1-point-improvement (e.g., from "severe" to "moderate") in their most severe symptom. This translated into an MCID range for CSMS0-6 of -0.23 to -0.21 points or -17% to -16%. Furthermore, a -0.34 point difference in RQLQ(S) compared to placebo was justified as clinically meaningful based on Phase III data from 2 registered SLIT grass tablets. Using this RQLQ(S) threshold as an anchor, an MCID of CSMS0-6 of -0.21 points (-16%) was derived using RESONATE. CONCLUSIONS:Both patient feedback and RESONATE results support an average MCID of -0.22 points on the CSMS0-6 scale and -16% on a composite primary endpoint scale, providing minimal thresholds to be achieved after AIT compared to placebo to conclude a positive Phase III trial outcome.

Background: Venom immunotherapy (VIT) is an effective treatment for yellow jacket venom (YJV) allergy. It is often based on mixtures of venom from different species. Recent taxonomic re-evaluation has revealed that widely used VIT preparations contain venom from Vespula alascensis, a North American species, rather than venom from the Palearctic Vespula vulgaris. Objective: To assess the allergenic relevance of V alascensis venom for European patients and evaluate its suitability for inclusion in VIT preparations. Methods: The ability of V alascensis and V vulgaris venom to activate effector cells from YJV-allergic patients from Germany was compared using the basophil activation test. Patients’ sIgE reactivity was assessed using ELISA, inhibition ELISA, CAP inhibition, and Western blot. Proteomic analysis of the venoms was also conducted. Results: Basophil activation tests showed highly similar activation profiles for V alascensis and V vulgaris venoms. Moreover, ELISA and inhibition analyses revealed comparable overall sIgE reactivity for both venoms. In contrast, Western blot analysis demonstrated similar sIgE profiles for antigen 5 allergens, although phospholipase A1 allergens were differentially detected. Proteomic analysis revealed no differences in the major allergens of the 2 venoms. Conclusion: This study demonstrates the functional similarity between V alascensis and V vulgaris venoms in allergic responses. Moreover, it highlights the clinical relevance of V alascensis for YJV-sensitized European patients and supports its inclusion in YJV VIT preparations in Europe.

Background Peanut allergy (PA) is one of the most prevalent food allergies with a lack of favorable safety/efficacy treatment. A cucumber mosaic virus-like particle expressing peanut allergen component Ara h 2 (VLP Peanut) has been developed as a novel therapeutic approach for PA. Objective We assessed the tolerogenic properties and reactivity of VLP Peanut. Methods Whole blood and peripheral blood mononuclear cells were collected from 6 peanut-allergic children. Modulation of dendritic cells (DCs), T cells, and B cells, stimulated with VLP Peanut, Ara h 2, and whole peanut extract in vitro, were assessed by quantitative real-time PCR and flow cytometry, respectively. Basophil and skin reactivity in response to VLP Peanut was assessed by basophil activation test and skin prick test, respectively. Results VLP Peanut showed beneficial biochemical properties, fit for use in clinical studies. VLP Peanut induced IFN-gamma(+) T(H)1 (P < .05) while having reduced capacity to elicit proliferation of T(H)2, allergen-specific T(H)2, and IL-4(+)-T follicular helper cells. Moreover, VLP Peanut is associated with upregulation of DC1-associated genes (MX1) compared to Ara h 2 and whole peanut extract. VLP Peanut was the most prominent at inducing IL-10(+) regulatory B cells (P < .05). Unbiased clustering analyses identified metaclusters of T and B cells targeted by VLP Peanut. Finally, VLP Peanut had reduced capacity to elicit high- and low-affinity IgE receptor-mediated responses compared to Ara h 2 or whole peanut extract (all P < .05). Finally, in an open-label first-in-human cohort of 6 peanut-allergic adults, administration of increasing concentration of VLP Peanut through skin prick test was tolerated and demonstrated no development of skin reactivity. Conclusions VLP Peanut displayed tolerogenic properties by modulating DCs, T cells, and B cells in vitro. Preliminary findings of skin reactivity using VLP Peanut in 6 peanut-allergic adults was safe and well tolerated in an open-label phase 1 study. Clinical Trial Identifier PROTECT, NCT 05476497

Background:Allergen Immunotherapy (AIT) is an effective treatment for patients with pollen, house dust mite, or venom allergy, but treatment adherence can be challenging. Patient preferences play a crucial role in acceptance and adherence to AIT, but little is known about these preferences. This study aimed to understand patient preferences for AIT and how these preferences influence treatment acceptance. Methods:A conjoint analysis was conducted among 750 participants from 7 European countries who were allergic to pollen (n = 700) or Hymenoptera venom (n = 50) and had not previously received AIT. Participants were asked to choose between hypothetical AIT products with different attributes, including product type, initial up-dosing posology, potential future risks, and side effects. The relative importance of each attribute was calculated, and sensitivity analyses were performed to assess the impact of specific attribute levels on patient preference. Results:Potential future risk is the attribute with the strongest impact on the importance score for patient preference in both pollen (44%) and venom (41%) allergic patients, followed by side effects (24% for pollen and 35% for venom allergy). Product type was less important, with a 22% importance score in both populations, and dosing schedules were not important at all, with a 2% importance score for pollen and an 11% importance score for venom-allergic patients. Accumulation of foreign material/substance in the body had the largest negative impact on patient preference, with drops of -24.7% (pollen) and -23.6% (venom), respectively. Conclusions:Understanding patient preferences is essential for optimizing the design and delivery of AIT. Different side effects and risk profiles of AIT products can influence patient treatment acceptance the most, and healthcare professionals may not always be aware of it. Future research should focus on developing AIT products that align with patient preferences with simultaneously very high effectiveness to improve adherence and treatment outcomes.

Background/Objectives: The guideline on allergen-specific immunotherapy of the European Academy of Allergy and Clinical Immunology recommends subcutaneous allergen-specific immunotherapy for the treatment of allergic rhinitis in children and adults with moderate to severe symptoms. The five years cohort study described below was designed in 2020 to demonstrate non-inferiority in terms of safety, tolerability and efficacy in a paediatric population compared with adult patients treated with microcrystalline tyrosine-adsorbed allergoids for their tree and grass pollen allergy in a perennial setting. Here, we present the preliminary findings from the first year. Methods: The Combined Symptom and Medication Score was chosen as the primary endpoint of this therapy. Secondary endpoints include the Rhinoconjunctivitis Quality of Life Questionnaire, the retrospective Rhinoconjunctivitis score, the Asthma Control Test and the Rhinitis Control Test, as well as an analysis of adverse drug reactions. Results: A total number of 320 patients were enrolled into this study, with 129 of these patients in the age group between 5 and 17 years and 191 patients in the adult age group. Mean Combined Symptom and Medication Score values did not differ significantly between minors and adults in the first pollen season after treatment induction. The retrospective score showed a strong and significant reduction in rhinoconjunctivitis and asthma symptoms. Treatment was well tolerated, with more than 80% of patients reporting no adverse drug reactions. Conclusions: The validity of this study approach of a cohort study has been confirmed by this first interim analysis for the initial course of therapy in the first year.

In the original publication [...].

Seit 2008 wird mit dem Beginn der Therapieallergene-Verordnung (TAV) in Deutschland der Zulassungsprozess für die Entwicklung von Produkten zur allergenspezifischen Immuntherapie (AIT) reguliert, die vorher schon als Individualrezepturen erhältlich waren. Ein entscheidender Aspekt im Zulassungsprozess von Medikamenten ist im Allgemeinen die Etablierung einer soliden Dosis-Wirkungs-Beziehung, die für den Behandlungserfolg des am Ende dieses Prozesses zugelassenen Produkts maßgeblich ist. Bisher gibt es jedoch nur wenige umfassende Studien zur Dosis-Wirkungs-Beziehung in der AIT, denn diese zu etablieren war bislang eine Herausforderung in diesem Feld. Faktoren, die diesen Prozess erschweren, sind unter anderem hohe Placeboeffekte, die Variabilität der Studienendpunkte und insbesondere bei nativen Allergenprodukten ein enges therapeutisches Fenster und Sicherheitsprofil. Die Phase-II-Studien zur MATA-MPL-Plattform für Birken- sowie Gräserpollen liefern erstmals klare, signifikante Dosis-Wirkungs-Daten, die entscheidend für die Optimierung der AIT sind. Die MATA-MPL-Plattform, die modifizierte Allergene (Allergoide) mit mikrokristallinem Tyrosin (MCT) und MPL (Monophosphoryl-Lipid-A) als Adjuvanzsystem kombiniert, konnte in den Phase-II-Studien eine ED50 und eine Plateaubildung für das Birken- sowie das Gräserallergoid nachweisen. Dies stellt eine bedeutende Weiterentwicklung im Feld der AIT dar, da so für die nachfolgenden Phase-III-Studien die optimale Dosis für sowohl Dosis-Wirkung als auch Tolerabilität ausgewählt werden konnte. Die MATA-MPL-Plattform zeigt damit eine stabile Dosis-Wirkungs-Beziehung über verschiedene Allergene hinweg und unterstreicht die zentrale Rolle gut definierter Dosisfindungsstudien als Voraussetzung für erfolgreiche Phase-III-Studien für die Weiterentwicklung der AIT. Zitierweise: Werminghaus P, Becker S, Klimek L, Cuevas M, Rosewich M, Hermanns F, Graessel A, de Kam P-J, Kramer M F. The pivotal role of the optimal dose in allergen immunotherapy. Allergo J Int 2025;34:10-4 https://doi.org/10.1007/s40629-024-00322-8

BACKGROUND:A short-course pre-seasonal subcutaneous injection of PQ Grass is clinically effective for the treatment of allergic rhinitis, though its mechanism remains unclear. The aim of the study was to interrogate immunological mechanisms induced by PQ Grass conventional and extended regimens. METHODS:A RDBPC exploratory field study involving participants that either received injections of PQ Grass with a cumulative dose of 27,600 SU conventional (six once weekly injections) or extended regimen (three once weekly injections followed by three once monthly injections) or placebo containing microcrystalline tyrosine (MCT) (placebo + MCT) or saline (placebo) was performed. Humoral, cellular, and molecular responses were assessed at baseline (V1), end of treatment, prior to grass pollen season (V12) and end of pollen season (V15). Immunoglobulin analyses and cellular/gene microarray analyses were performed in the sub-study cohort consisting of PQ Grass Conventional (n = 25 and n = 10, respectively), PQ Grass Extended (n = 26 and n = 10, respectively), Placebo with MCT (n = 13 and n = 5, respectively), and Placebo (saline; n = 12 and n = 5, respectively). RESULTS:Both PQ Grass regimens, conventional and extended, were associated with improvement in total combined scores (TCS) with a relative difference of -35.0% (p = 0.03) and -40.8% (p = 0.01) against placebo with MCT, respectively. Both PQ Grass treatment regimens were associated with increases in the sIgG4/sIgE ratio (all, p < 0.05) and induction of IgA1 (all, p < 0.05) and IgA2 (all, p < 0.01) compared to placebo groups. Nasal fluid (p < 0.01) and serum (p < 0.05) blocking antibodies are functional and have the capacity to inhibit allergen-IgE complex formation and binding to B cells in the PQ Grass groups. In vitro cellular and microarray gene analyses demonstrated that the extended PQ Grass regimen was more proficient in modulating the immune response towards a tolerogenic milieu by dampening pro-inflammatory type 2 immune response and the associated cytokines (p < 0.05), immune deviation towards a Th1 response (p < 0.05), and induction of FOXP3+ Treg cells (p < 0.05). CONCLUSIONS:For the first time, we highlight differential mechanisms of tolerance induction by PQ Grass, with the extended regimen being superior in modulating T cell compartments. TRAIL REGISTRATION:Trial number: PQGrass309, EudraCT number: 2020-000408-13, Clinicaltrials.gov identifier: NCT04687059, and NCT05540717.

ABSTRACT Background PQ Grass 27600 SU (PQ Grass) cumulative dose is a pre‐seasonal, six‐injection, aluminium‐free, modified subcutaneous immunotherapy product under development for the treatment of allergic rhinitis (AR). A pivotal Phase III randomised double‐blind, placebo‐controlled clinical trial was performed to evaluate the efficacy and safety of PQ Grass in subjects with seasonal AR. Methods An adaptive group sequential trial PQGrass306 (G306) with one pre‐defined interim analysis was designed, using 2 parallel groups applying a 1:1 active versus placebo randomisation of patients aged 18–65. The primary efficacy endpoint was the EAACI (European Academy of Allergy and Clinical Immunology) Combined Symptom and Medication Score (EAACI‐CSMS 0–6 ) averaged over the peak grass pollen season (GPS). Results 858 subjects were screened and 555 subjects were randomised. Based on the results of the pre‐defined interim analysis, the trial was stopped for success showing superiority in favour of PQ Grass. The primary endpoint EAACI‐CSMS 0–6 (peak GPS) demonstrated a highly significant and clinically meaningful point difference of PQ Grass over placebo of −0.27 points (95% CI: −0.42 to −0.12), corresponding to a relative difference of −20.3% ( p = 0.0005). Highly consistent and beneficial results were obtained for PQ Grass for all key secondary endpoints. Significant induction of blocking IgG4 and IgA antibody subclasses occurred. PQ Grass was well tolerated, and no unexpected safety signals occurred. Conclusions This pivotal Phase III trial demonstrated a significant and clinically meaningful effect on the primary endpoint as well as highly consistent secondary endpoint results and a supportive safety profile.

Aluminum oxyhydroxide (AlOOH) is the most widely used vaccine adjuvant, but its known adverse effects prompt the finding of other, safer alternative adjuvants. This study compares in sheep the global performance and safety of vaccine prototypes against bluetongue virus (BTV) formulated with AlOOH, biomimetic apatite nanoparticles (ApNPs), and microcrystalline tyrosine (MCT). Five groups of 6 sheep were included in the study: control, BTV serotype 4 alone, and BTV-4 combined either with AlOOH, ApNPs, or MCT. Adjuvants were fully characterized. Group specific antibodies against BTV-4 were observed in all treatment groups, including BTV-4 alone. After booster inoculation, ApNPs or MCT groups responded immediately, and it was delayed for BTV-4 and AlOOH groups. Comparable neutralizing antibody responses were observed in all treatment groups but were earlier for BTV-4, ApNPs, and MCT groups when compared with the AlOOH group. No significant systemic alterations were observed during the study. The AlOOH group developed more pronounced local reactions that persisted throughout the 133-day study and were evident as post-mortem granulomas. ApNPs and MCT are biocompatible, safer, and viable alternative adjuvants for sheep vaccines. BTV alone might also be suitable for this purpose. This work is the first demonstrating the suitability of biocompatible alternative adjuvants in sheep vaccines.

Hymenoptera venom extracts for allergen-specific immunotherapy (AIT) are marketed with the attributes “purified” or “highly purified” or “non-purified.” However, all manufacturing processes include purification steps and are subject to the same requirements of the European Pharmacopoeia. European and national guidelines confirm that “purified” and “non-purified” Hymenoptera venom AIT (VIT) do not differ in their effectiveness and frequency of systemic adverse events (AE). Differences in preserving natural venom composition appear more relevant. Hymenoptera venom AIT is considered the success model for AIT. Protection rates of close to 100

Type I hypersensitivity, also known as classical allergy, is mediated via allergen-specific IgE antibodies bound to type I FcR (FcεRI) on the surface of mast cells and basophils upon cross-linking by allergens. This IgE-mediated cellular activation may be blocked by allergen-specific IgG through multiple mechanisms, including direct neutralization of the allergen or engagement of the inhibitory receptor FcγRIIb which blocks IgE signal transduction. In addition, co-engagement of FcεRI and FcγRIIb by IgE-IgG-allergen immune-complexes causes down-regulation of receptor bound IgE, resulting in desensitization of the cells. Both, activation of FcεRI by allergen-specific IgE and engagement of FcγRIIb by allergen-specific IgG are driven by allergen-binding. Here we delineate the distinct roles of antibody affinity versus avidity in driving these processes and discuss the role of IgG subclasses in inhibiting basophil and mast cell activation.