Venom immunotherapy: adverse reactions and treatment failure

Venom Immunotherapy: From Proteins to Product to Patient Protection

In this review, we outline and reflect on the important differences between allergen-specific immunotherapy for inhalant allergies (i.e., aeroallergens) and venom-specific immunotherapy (VIT), with a special focus on Venomil® Bee and Wasp. Venomil® is provided as a freeze-dried extract and a diluent to prepare a solution for injection for the treatment of patients with IgE-mediated allergies to bee and/or wasp venom and for evaluating the degree of sensitivity in a skin test. While the materials that make up the product have not changed, the suppliers of raw materials have changed over the years. Here, we consolidate relevant historical safety and efficacy studies that used products from shared manufacture supply profiles, i.e., products from Bayer or Hollister-Stier. We also consider the characterization and standardization of venom marker allergens, providing insights into manufacturing controls that have produced stable and consistent quality profiles over many years. Quality differences between products and their impacts on treatment outcomes have been a current topic of discussion and further research. Finally, we review the considerations surrounding the choice of depot adjuvant most suitable to augmenting VIT.

Global View on Ant Venom Allergy: from Allergenic Components to Clinical Management

Hymenoptera venom allergy is characterised by systemic anaphylactic reactions that occur in response to stings from members of the Hymenoptera order. Stinging by social Hymenoptera such as ants, honeybees, and vespids is one of the 3 major causes of anaphylaxis; along with food and drug exposure, it accounts for up to 43% of anaphylaxis cases and 20% of anaphylaxis-related fatalities. Despite their recognition as being of considerable public health significance, stinging ant venoms are relatively unexplored in comparison to other animal venoms and may be overlooked as a cause of venom allergy. Indeed, the venoms of stinging ants may be the most common cause of anaphylaxis in ant endemic areas. A better understanding of the natural history of venom allergy caused by stinging ants, their venom components, and the management of ant venom allergy is therefore required. This article provides a global view on allergic reactions to the venoms of stinging ants and the contemporary approach to diagnose and manage ant venom allergy.

Precision Medicine in Hymenoptera Venom Allergy: Diagnostics, Biomarkers, and Therapy of Different Endotypes and Phenotypes

Allergic reactions to stings of Hymenoptera species may be severe and are potentially fatal deviations of the immunological response observed in healthy individuals. However, venom-specific immunotherapy (VIT) is an immunomodulatory approach able to cure venom allergy in the majority of affected patients. An appropriate therapeutic intervention and the efficacy of VIT not only depend on a conclusive diagnosis, but might also be influenced by the patient-specific manifestation of the disease. As with other diseases, it should be borne in mind that there are different endotypes and phenotypes of venom allergy, each of which require a patient-tailored disease management and treatment scheme. Reviewed here are different endotypes of sting reactions such as IgE-mediated allergy, asymptomatic sensitization or a simultaneous presence of venom allergy and mast cell disorders including particular considerations for diagnosis and therapy. Additionally, phenotypical manifestations of venom allergy, as e.g. differences in age of onset and disease severity, multiple sensitization or patients unsusceptible to therapy, are described. Moreover, biomarkers and diagnostic strategies that might reflect the immunological status of the patient and their value for therapeutic guidance are discussed. Taken together, the increasing knowledge of different disease manifestations in venom hypersensitivity and the growing availability of diagnostic tools open new options for the classification of venom allergy and, hence, for personalized medical approaches and precision medicine in Hymenoptera venom allergy.

Exclusive Bee Venom Allergy: Risk Factors and Outcome of Immunotherapy

INTRODUCTION

Venom immunotherapy (VIT) is considered to be the gold-standard treatment for patients with Hymenoptera venom allergy. Data regarding VIT in bee venom (BV) allergic patients are scarce.

AIM

The aim of this study was to evaluate the outcome of VIT in patients with exclusive BV allergy and to try to define risk factors for VIT-induced systemic reactions (VIT-ISR) and VIT failure.

METHODS

This is a retrospective study including data from all BV allergic patients that were treated by VIT in the Allergy Unit at the Meir Medical Center in the years 1995-2018.

RESULTS

Two hundred and forty-seven patients with exclusive BV allergy were included; 206 (83.4%) preferred to undergo rush buildup. Sixty-nine patients (27.9%) had at least 1 reaction during buildup, with the c-kit mutation being the only significant risk factor (100 vs. 28.9%, p = 0.02). Female gender (25.4 vs. 13.3%, p = 0.04), conventional buildup schedule (26.8 vs. 14.1%, p = 0.04), and c-kit mutation (100 vs. 16.8%, p < 0.01) but not tryptase level were found to be significantly more frequent in recurrent reactors. Females (20.3 vs. 9%, p = 0.03), patients with severe systemic reaction to the index sting (24.3 vs. 9.5%, p = 0.004), and c-kit mutation (66 vs. 12%, p = 0.05) but not tryptase level were found to be risk factors for severe systemic reactions.

CONCLUSION

Despite the considerably high rate of VIT-ISR in patients with exclusive BV allergy, VIT can be performed safely and efficiently. C-kit mutation, and not basal serum tryptase level, seems to be a preferable biomarker for VIT-ISR in these patients.

Venom allergy treatment practices in Poland in comparison to guidelines: next edition of the national audit

INTRODUCTION

Venom immunotherapy treatment (VIT) is the only causal treatment of hymenoptera venom anaphylaxis, which aims to provide long-lasting immunoprotection against severe reactions to subsequent stings.

AIM

To reassess the compliance of VIT procedures in the Polish allergy centres with the European guidelines.

MATERIAL AND METHODS

A structured questionnaire survey conducted in all 33 VIT-centres. The response rate was 94%.

RESULTS

The ultrarush initial protocol was the most common protocol (71%, n = 22), usually lasting for 3.5 h (50%, n = 7). The most frequent (36%, n = 11) time interval from the initial to the first maintenance dose (MD) was 14 days, ranging from 7 to 35 days. All centres used an MD of 100 μg. The most frequent time interval between subsequent MDs was 4 weeks (58%, n = 18). Five years' of VIT was declared by 71% (n = 22). Before the termination of treatment, more than half of the centres (58%, n = 18) performed sIgE and almost half (42%, n = 13) performed skin tests. To confirm VIT efficacy, few centres (26%, n = 8) conducted the sting challenge. About half of centres provided the patients with an adrenalin auto-injector both at the time of initial diagnostics and at the end of treatment. More than half (55%, n = 17) used antihistamines in all patients. Almost half (45%, n = 14) declared to stop treatment with β-blockers and almost one fourth (23%, n = 7) discontinued angiotensin-converting-enzyme inhibitors.

CONCLUSIONS

In the most important procedures, there is a very high compliance with the guidelines. In the areas where the guidelines are not precise, we observed a large spread of results.

Venom Immunotherapy in High-Risk Patients: The Advantage of the Rush Build-Up Protocol

BACKGROUND

Venom immunotherapy (VIT) is considered to be the gold standard treatment for patients with hymenoptera venom allergy. This treatment induces systemic reactions (SR) in a significant number of patients.

OBJECTIVE

To evaluate the outcome of VIT in patients with known risk factors for VIT-induced SR and to compare rush VIT (RVIT) and conventional VIT (CVIT).

METHODS

All of the patients who received VIT and had at least one of the following risk factors were included: current cardiovascular disease, uncontrolled asthma, high basal serum tryptase, current treatment with β-blockers or angiotensin-converting enzyme inhibitors, and age >70 or <5 years.

RESULTS

Sixty-four patients were included, and most of them (52; 81.5%) were allergic exclusively to bee venom. Thirty-five (54.7%) patients underwent RVIT and 29 CVIT. The incidence of patients who developed SR during the build-up phase was similar for RVIT and CVIT (25.7 and 27.5%, respectively; p = 1). However, the incidence of SR per injection was significantly higher in CVIT than in RVIT (5.6 and 2.75%, respectively; p = 0.01). Most reactions (79.1%) were mild, limited to the skin. Most of the patients (92.1%) reached the full maintenance dose of 100 μg. This dose was reached by a significantly larger number of patients receiving RVIT compared to CVIT (100 and 82.7%, respectively; p = 0.01). None of the patients experienced exacerbation of their concurrent chronic disease during VIT.

CONCLUSION

VIT can be performed safely and efficiently in patients with risk factors for immunotherapy. In these patients RVIT appears to be safer and more efficient than CVIT.

Anaphylaxis to insect venom allergens: role of molecular diagnostics

Anaphylaxis due to Hymenoptera stings is one of the most severe consequences of IgE-mediated hypersensitivity reactions. Although allergic reactions to Hymenoptera stings are often considered as a general model for the underlying principles of allergic disease, diagnostic tests are still hampered by a lack of specificity and venom immunotherapy by severe side effects and incomplete protection. In recent years, the knowledge about the molecular composition of Hymenoptera venoms has significantly increased and more and more recombinant venom allergens with advanced characteristics have become available for diagnostic measurement of specific IgE in venom-allergic patients. These recombinant venom allergens offer several promising possibilities for an improved diagnostic algorithm. Reviewed here are the current status, recent developments, and future perspectives of molecular diagnostics of venom allergy. Already to date, it is foreseeable that component-resolution already has now or will in the future have the potential to discriminate between clinically significant and irrelevant sensitization, to increase the specificity and sensitivity of diagnostics, to monitor immunotherapeutic intervention, and to contribute to the understanding of the immunological mechanisms elicited by insect venoms.

[Intolerance of specific immunotherapy with Hymenoptera venom: jumping the hurdle with omalizumab]

Specific immunotherapy is a very effective and well-tolerated therapeutic option in patients with Hymenoptera venom allergy. Many patients can be successfully treated, and severe side-effects are rarely seen. In most cases local swelling of the injection site is noticed, whereas systemic reactions are uncommon. No reliable biomarkers to prove the positive response to the specific immunotherapy have been validated. But on the other hand the failure of the venom immunotherapy can be verified by performing a sting challenge test; in this case the maintenance dose of the venom immunotherapy has to be increased and the sting challenge test has to be repeated. This approach works well most of the patients. In rare cases severe anaphylactic reactions occur during the initiation of the venom immunotherapy due to individual risk factors. While in the past this necessitated discontinuation of the specific immunotherapy, the current situation has remarkably changed. Since the IgE-antibody omalizumab has been licensed for different indications, a new therapeutic option is available. We have employed this approach since 2005. We share our own practical experience as well as recent data, presenting a management approach for Hymenoptera venom allergy in high-risk patients.

Hymenoptera venom immunotherapy

Subcutaneous venom immunotherapy is the only effective treatment for patients who experience severe hymenoptera sting-induced allergic reactions, and the treatment also improves health-related quality of life. This article examines advances in various areas of this treatment, which include the immunological mechanisms of early and long-term efficacy, indications and contraindications, selection of venom, treatment protocols, duration, risk factors for systemic reactions in untreated and treated patients as well as for relapse following cessation of treatment. Current and future strategies for improving safety and efficacy are also examined. However, although progress in the past few years has been fruitful, much remains to be accomplished.

Clinical practice: Allergen-specific immunotherapy in children: facts and FAQs

Allergen-specific immunotherapy (SIT) in its various application forms represents the main treatment approach of IgE-mediated allergic diseases in adults and children. Despite this clear recommendation, many particularities of products, patient characteristics, and product availability in different countries hamper the use of allergen-specific immunotherapy in particular in children. The frequently asked questions by parents, patients, and physicians are the backbone of this review. Thus, the potentials and limitations of allergen-specific immunotherapy in children and adolescents will be highlighted. IgE-mediated allergic diseases are affecting about 20% of the population. They manifest commonly early in life, and hence, the use of SIT should be considered also early in the course of the disease.

Purified vs. nonpurified venom immunotherapy

PURPOSE OF REVIEW

Although highly effective, venom immunotherapy (VIT) may be responsible for local and systemic allergic reactions. There is a good theoretical basis for believing that purified aqueous and purified aluminium hydroxide adsorbed (so-called depot) extracts, commercially available in Europe, have the potential to reduce the incidence of VIT's side effects. The aim of this article is to review the literature on safety and effectiveness of purified preparations as well as compare them with nonpurified extracts.

RECENT FINDINGS

Old and new noncomparative studies reveal good tolerance of purified aqueous and purified depot extracts. In comparative trials purified extracts appear to be better tolerated than nonpurified extracts, whereas depot extracts seem to be safer than the corresponding purified aqueous preparation, especially in the prevention of severe large local reactions. The efficacy of purified aqueous and depot extracts is supported by studies using both sting challenge and in-field stings and is comparable to that of nonpurified preparations.

SUMMARY

The theoretical basis of the safer profile of purified extracts is supported by a number of clinical studies, making the use of purified depot preparations preferable for conventional treatment also by specialists with less experience in managing VIT. In specialized centres purified aqueous extracts may be preferred for faster build-up protocols. However, further prospective controlled studies are needed in order to evaluate the ability of purified extracts to reduce the frequency of severe systemic reactions over the corresponding nonpurified preparation.

Effectiveness of maintenance bee venom immunotherapy administered at 6-month intervals

BACKGROUND

Extension of the intervals at which maintenance venom immunotherapy (MVIT) is administered has been attempted for many years. However, published evidence on its effect, especially in intervals of longer than 3 months, is sparse.

OBJECTIVE

To examine whether the administration of a bee venom (BV) maintenance dose at 6-month intervals is safe and efficacious.

METHODS

The 3-month intervals at which venom-allergic patients were receiving their MVIT were gradually extended to 6 months. Systemic reactions (SRs) to immunotherapy injections or to field stings were regularly recorded. Patients who were allergic to BV alone or also to other venoms were deliberately sting challenged by a honeybee after reaching the 6-month interval.

RESULTS

The 3-month intervals were extended in 47 patients. A single patient (2%) developed an SR after receiving the injection at an interval of 4 months. Two field stings in 2 patients resulted in a mild SR in 1 patient. Of 14 sting-challenged patients, 3 (21%) developed an SR after the challenge. The 3 SRs occurred only among the 8 patients (38%) who were allergic to BV alone. The 3 patients with the SR to the challenge continued to receive the regular maintenance dose at monthly intervals 3 to 5 more times. Repeated sting challenges were then well tolerated in all 3 patients.

CONCLUSION

The administration of MVIT at 6-month intervals does not provide suitable protection in BV-allergic patients, and they should continue MVIT at the accepted 1- to 3-month intervals.

Premedication with Montelukast Reduces Local Reactions of Allergen Immunotherapy

BACKGROUND

Local reactions (LRs) are a very frequent side effect of specific immunotherapy with allergens and can impair patients' adherence. Antihistamine pretreatment--originally introduced as a safety measure to reduce anaphylactic side effects--has been the only treatment option for LRs so far, although these swellings usually do not appear immediately but after hours. We were interested whether pretreatment with the leukotriene antagonist montelukast would be better suited for preventing those reactions than pretreatment with the antihistamine desloratadine.

METHODS

Fifteen patients with a history of severe anaphylactic reactions to hymenoptera stings were enrolled into a prospective, double-blind, randomized, placebo-controlled pilot study. We selected a rush immunotherapy protocol consisting of 19 injections of hymenoptera venom administered over 5 consecutive days, where the majority is developing LRs, and counted the number of injections until an LR of >3 cm occurred. The patients were randomized to 3 treatment groups: premedication with placebo, 10 mg montelukast and 5 mg of the antihistamine desloratadine.

RESULTS

Compared with placebo, the occurrence of LRs (>3 cm) was significantly delayed by montelukast (p < 0.01, analysis of variance) but not by desloratadine (p = 0.19). The difference between montelukast and desloratadine was close to significant (p = 0.054). Itching, recorded on a scale from 0 to 5, did not differ between the 3 groups.

CONCLUSION

Montelukast can be useful in the prevention of LRs after specific immunotherapy.

Immunotherapy of hypersensitivity to hymenoptera venom

Insect sting allergy is a common condition with a risk of life-threatening anaphylaxis. After a severe reaction, the fear of being restung can significantly reduce quality of life. Venom immunotherapy (VIT) is a highly effective treatment of the underlying type I-sensitisation. This review addresses the mechanisms of immune modulation by VIT and outlines current clinical application. Although highly effective in the majority of patients, VIT fails in a few individuals. It can also cause systemic allergic side effects, restricting its application to physicians trained in the treatment of anaphylaxis. This review discusses several new strategies to overcome these problems, which are presently a promising focus of research. These include the use of new adjuvants, of recombinant and genetically engineered venom allergens, as well as vaccination with peptides.

Insect sting allergy. A study from 1980 to 2003 of patients who started treatment with venom immunotherapy between 1980 and 1998

Background

Previously we treated patients with insect sting allergy with venom immunotherapy (IT) using whole body insect extracts. From 1980 we changed to insect venoms. The purpose of this study was to analyse data from the patients in order to improve our treatment.

Methods

This is an open, single centre study on patients treated with venom IT 14 years or older with a history of a systemic allergic reaction to an insect sting, a positive skin prick test (SPT) or a positive RAST and willingness to comply with five years of IT. Clinical and laboratory data were registered prospectively at the start of IT and after five years of treatment until 2003 on patients who started IT between 1980 and 1998. Questionnaires were answered in 1989, 1993 and 2003. Statistical analysis was done with Pearson's chi square, Fisher's exact or the t-test.

Results

Of 315 patients treated, 44 were given bee, 248 common wasp and 23 both venoms. Of the common wasp sting incidents 5.5 % resulted in a severe allergic reaction (SAR) during adequate IT and 22% after cessation. Seventy-one per cent of the patients carried epinephrine. Precautionary steps were taken by 77% of the patients during or after inadequate IT. On or after adequate IT 83% felt completely or substantially safe. Surprisingly 29 % of those inadequately treated felt safer and 50% were satisfied with having had the opportunity to be treated. The SPT became negative in 68% of the wasp allergic patients after five years of adequate IT. Increased risk of experiencing SAR to a future sting in wasp allergic patients after cessation of adequate IT was significantly associated with a SAR due to IT during the rush regimen. SAR due to IT occurred very rarely during maintenance dosing.

Conclusion

Adequate venom IT is very effective while ongoing but somewhat less effective after cessation, while inadequate treatment gives poor results. More of our patients should complete five years of IT and some should continue IT. The type of reaction to IT during incremental dosing may be of help in deciding who should continue beyond five years. Maintenance IT may be taken over by the general physician.