Subcutaneous allergen immunotherapy reduces asthma risk, improves symptom control
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Key takeaways:
- Allergen immunotherapy prevented the onset of asthma for those with house dust mite allergy.
- The therapy also slowed the progression of allergic rhinitis and asthma.
Subcutaneous allergen immunotherapy for house dust mite reduced the number of prescriptions for allergic rhinitis and asthma medications, according to a study published in The European Journal of Allergy and Clinical Immunology.
Compared with a control group that did not use allergen immunotherapy (AIT), the subcutaneous immunotherapy (SCIT) group showed a reduced probability for asthma onset as well as for developing asthma from allergic rhinitis (AR) over time, Marek Jutel, MD, PhD, professor and head of the department of clinical immunology at the Wroclaw Medical University and director of the ALL-MED Medical Research Institute in Wroclaw, Poland, and colleagues wrote.
The retrospective, observational, comparative cohort study was conducted in Germany using anonymized claims data from IQVIA LRx.
Participants included house dust mite (HDM) allergic subjects aged 5 to 70 years divided into an SCIT group (n = 892) and a control group (n = 2,676) evaluated over a 6-year follow-up.
Subjects in the SCIT group received their first prescription of SCIT with a native HDM product between 2009 and 2013. The control group was matched in a 3:1 ratio and received prescriptions for only symptomatic AR medication with an evaluation period of up to 6 years ending in February 2017. The study measured the progression of AR and asthma, asthma occurrence and time to the onset of asthma after at least 2 years of treatment.
The SCIT group was treated with Novo-Helisen Depot (Dermatophagoides pteronyssinus 100%, D. farinae 100%, D. farinae/D. pteronyssinus 50%/50%; Allergopharma GmbH & Co. KG).
Results
The progression of AR and asthma after up to 6 years of follow-up was measured by counting numbers of prescriptions in the retrospective claims database analysis.
Mean annual AR prescription numbers fell from 0.48 before the index to 0.17 in the follow-up period for the SCIT group for a 62.8% reduction (P < .0001) but remained the same at 0.48 for the control group. Subanalyses showed that children and adolescents initially had more allergic rhinitis prescriptions (mean, 0.54; standard deviation [SD], 1.06) than adults (mean, 0.45; SD, 1.1), which after follow-up showed a reduction in the SCIT group by 53% (P < .0001) in underage patients and 66.5% (P < .0001) in adults.
The mean number of asthma prescriptions in the SCIT group dropped by 2.51 a year compared with 1.63 in the control group. This was equivalent to a 42.4% reduction in asthma prescriptions in the SCIT group compared with the non-AIT group (P = .0003). The SCIT group showed comparable results in children/adolescents (47.2%; P = .0051) and adults (39%; P = .0166).
Within the SCIT group, 10.2% developed asthma from the index date up to the 6-year follow-up, whereas 13.1% developed asthma in the control group. Logistic regression showed that the SCIT group had a 27% less chance of developing asthma than the control group (OR = 0.73; 95% CI: 0.559-0.954).
The times to onset of asthma were measured using Kaplan-Meier curves, which showed the groups starting to diverge around 15 months after starting therapy, with the SCIT group showing fewer asthma developments.
After 15 months, the SCIT group curve stayed consistently above the control group.
The authors concluded that the logistic regression for the occurrence of asthma showed a significant and similar effect (OR = 0.73), which meant that the native HDM SCIT product was effective in preventing asthma.
Reference:
Perspective
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Michael S. Blaiss, MD, FACAAI, FAAAAI
The findings from this real-world data Germany study confirm previous studies that subcutaneous allergen immunotherapy with house dust mite can lead to immunomodulation and decrease the need for AR treatment and the development or time of onset of asthma.
It is important to note that in this study that a house dust mite depot immunotherapy containing aluminum hydroxide was used that is not available in the United States. Aluminum hydroxide depot immunotherapy acts as an adjuvant in allergen immunotherapy that may enhance allergen immunogenicity and tolerability but also raises IgG and IgE titers. Presently, the exact mechanism of action of aluminum hydroxide as an adjuvant remains unknown.
Also, since this is a real-world study using chart review and not a placebo-controlled study, there may be problems such as missing data and lack of randomization, although the strength of this study is having 6-year data, which is important in determining the long-term effect of allergen immunotherapy.
This study does confirm practice that AIT with house dust mite, either subcutaneous or sublingual tablet, will decrease AR symptoms, requiring less need for AR medication. Also, over time it will decrease the risk for development and/or decrease time of onset of asthma in these patients. Previous studies have also demonstrated that AIT will decrease the amount of medication needed for asthma compared with no immunotherapy.
It is worth pointing out that it took 15 months to see an effect on asthma in this study. It is important that the clinician and patient realize that AIT is a long-term process to get optimal benefit. This leads to the recommendation of 3 to 5 years of immunotherapy treatment.
AIT is underused in the AR population. This study points out the importance of this modality for not only treatment of AR, but also its effects on asthma. Preventing asthma or decreasing time of onset is important for the health of the patient and also the health care system, as it can lead to lower costs.
Patients with AR should be offered AIT as part of a shared decision-making process in determining care for their condition.
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