Efficacy and safety profile of animal dander immunotherapy: a multicentre UK studyTo the Editor,The prevalence of animal dander sensitisation has increased worldwide, with sensitisation rates in Europe as high as 26.3% to cat dander and 27.2% to dog dander.1 These aeroallergens can be found in environments such as schools, public transport or places of work, where the animals do not live and sensitisation may occur by direct or indirect contact.2 The recommended treatment for most patients in the UK is avoidance, which is not always practical or possible, particularly in public areas or places of work.Evidence for animal dander allergen specific immunotherapy (AIT) is limited, with cat dander AIT demonstrating the most consistent improvement after 12 months in a small study.3 Studies of dog dander AIT over the past 40 years have not confirmed statistically significant clinical efficacy.3,4 Other therapies described include horse dander and rat epithelium AIT.5,6In view of the limited data on animal AIT, we conducted a multi-centre review. Data on 35 patients aged 17 to 62 years (demographics in Table s1) treated with cat, dog and horse dander subcutaneous (SCIT) or sublingual (SLIT) AIT within five allergy services was analysed. All patients had confirmation of sensitisation by specific IgE or skin-prick testing. The commonest reason for AIT was workplace exposure, almost a third of which were veterinary workers (Supplementary Table s2). Efficacy was measured with different methods across different patients (Table 1). Side effects are reported in Table 2.Our data shows a higher compliance rate for SCIT patients, with 3-year completion rates at 60% compared with SLIT at 43%, accounting for 4 patients currently on treatment, which aligns with published data (Table 1). The most common reason for incomplete therapy was loss to follow-up and there were varied reasons for this (Supplementary table S3).For those who completed the full 3-year therapy, there were excellent efficacy rates for both SCIT and SLIT with 100% of patients achieving either complete or partial response (Table 2). Patient reported symptoms was the most used indicator of efficacy. A negative in-hospital cat challenge was performed in one patient and a negative home dog provocation in one patient. Efficacy was better in SCIT, with 100% complete response compared with 67% complete response in SLIT. All products established a complete response, except Oralvac cat and horse.The side effect profiles were acceptable with only one patient receiving cat dander SCIT reporting systemic side effects of rhinitis and wheeze during updosing. This patient completed updosing but did not complete maintenance therapy due to side effects. The majority of reported side effects were limited to localised reactions (Table 2). 3 SLIT patients withdrew from treatment due to undocumented side effects. Overall, 23/35 (66%) patients reported no side effects.Although numbers are small, our data demonstrates significant benefits from animal dander AIT with high efficacy rates, and side effects mainly limited to mild, localised reactions. The therapy may be most beneficial in those who are unable to avoid exposure, most commonly from workplace, or those suffering from systemic symptoms, such as asthma exacerbations when exposed to dander without the presence of the animal itself, making avoidance near impossible. Despite the benefits, animal dander AIT is used less than other inhalant allergens.One limitation of the study is that we do not have long-term follow-up data, so the durability of the response is uncertain. Adherence is also a significant issue and means to improve this should be considered.There is limited research on animal dander AIT compared with other aeroallergens, and our data has shown positive findings, although mostly with cat and dog dander. Larger cohorts are required to understand the full benefits of animal dander AIT.Table 1. Documented efficacy and compliance rates for those who completed 3 years AIT therapy.

Efficacy and safety of a 7-week immunotherapy protocol with aluminium hydroxide absorbed hymenoptera venomTo the Editor,Hymenoptera venom allergy can cause life threatening anaphylaxis in patients sensitised to wasp and bee venom. Venom immunotherapy is effective in 77%‐84% of patients treated with honeybee venom and in 91%‐96% of patients receiving vespid venom1. Adverse events are usually rare and mild, and symptoms occur in only 4.3%‐11.4% of patients during the updosing1.A variety of therapy regimes exist for the updosing phase, from conventional, rush, ultrarush or clustered modalities1,2. Current conventional protocols are time‐consuming for patients, and some patients decline the potentially life-saving treatment due to the time commitment required for immunotherapy. Adverse events appear to be less frequent in conventional protocols during the updosing phase compared to rush and ultrarush protocols1,2; however, patients may remain unprotected for weeks as it takes considerable time to reach the maintenance dose.The only licensed venom immunotherapy product in the UK is Alutard SQ® (ALK Abelló) for Vespula and Apidae venom. The SPC recommends updosing with a 7-week clustered protocol or 15- or 25-week conventional protocol.To enhance the acceptance of treatment and increase compliance, we reduced the length of the SPC protocol. Another significant factor was the COVID-19 pandemic, which significantly reduced outpatient capacity to comply with social distancing.Based on previous data using the same product3, we introduced a shorter updosing protocol with 8 injections in 7 weeks and monitored its efficacy and safety. We used this in a wider age range of patients, including one patient with indolent mastocytosis and more patients with severe sting reactions.Seventy‐four patients aged 17 to 85 years with a history of a systemic sting reaction to vespid and apidae stings grade 2-4 were included (Table 1). Further information about patient selection and the updosing protocol is in supplementary file S1.We managed to retain all the patients during updosing and maintenance, and no dose reduction was needed.During updosing, there were no objective systemic adverse reactions recorded. Only one objective systemic adverse reaction was documented during maintenance, which was mild and limited to the skin. There were 6 incidences of mild and subjective systemic reactions during updosing and maintenance, which included symptoms of feeling hot, dizzy and itchy. The symptoms were treated with additional antihistamines with no change in regime required. We had a lower incidence of systemic reactions at 1.4% compared to Schrautzer et al3, who reported objective systemic reactions in 3.9% of patients during just the updosing phase.9.5% of our patient cohort reported large localised reactions throughout both the updosing and maintenance phase, which generally only occurred once or twice during the full treatment course.The prevalence of cardiovascular disease and treatment with beta-blockers were not related to the occurrence of side effects.Reactions to field stings were monitored to assess efficacy as sting challenges are not performed in the UK. 20 patients had field stings and all reported localised reactions. Some patients were stung by multiple insects (such as one patient who was stung by 19 insects at one time) and this was more common in beekeepers.We have extended the work of Schrautzer et al3 and demonstrated the efficacy and safety of their 7-week protocol in a large group of patients in a real-world setting. We have also demonstrated safety and efficacy of the 7-week protocol for Alutard SQ® apidae immunotherapy. Our data includes a larger group of patients with more severe reactions. Interestingly, our data also shows a lower number of reactions to immunotherapy treatment.The quicker updosing protocol improved patients’ acceptance of treatment and increased the efficiency of our immunotherapy clinic in terms of time and cost for patients, and medical staff.

Background: The occurrence of prodromes has been associated with swelling in hereditary angioedema (HAE). The aim of the study was to analyse the frequency of prodromal signs, the level of awareness among HAE patients and to understand the actions taken by patients when they experienced them. Methods: An online survey to assess patient experiences of prodromal symptoms was conducted among 208 HAE patients from the UK and Spain. Results: 60% of HAE patients who experience prodromes can always or usually predict an impending swelling. Almost 40% of participants noticed prodromes within the 2 hours preceding an HAE attack. Tiredness/fatigue (64%), pressure or tightness in the skin (53%) and abdominal pressure (52%) were the most reported early symptoms. C1-esterase inhibitor (C1-INH) and icatibant were prescribed to 75% and 65% of participants, respectively. 56% of participants in the UK reported self-medicating at the time of prodrome, whereas 65% of patients in Spain preferred to wait or relax when early symptoms began. 30% of patients said they usually took their medication within 1 hour of experiencing the prodrome. The percentage of patients who needed only one injection to treat the attack increased when patients took their medication early in the prodrome (from 55 to 66%). Conclusions: The majority of patients who have early symptoms were usually or always able to predict that a swelling would occur. Early treatment of HAE attacks is associated with less medication usage, but there is still no common understanding of what ‘early treatment’ means.

A document by Anthony Dorr. Click on the document to view its contents.

A document by Manisha Ahuja. Click on the document to view its contents.