Early efficacy in subcutaneous immunotherapy for allergic rhinitis predicts later response
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Key takeaways:
- Patients began experiencing improvements in symptom scores after 8 weeks of care.
- There were significant correlations between improvements at 8 weeks, 6 months and 1 and 2 years and at 3 years.
Early efficacy in treatment may predict clinical response to subcutaneous immunotherapy for allergic rhinitis due to house dust mite allergy at 3 years, according to a letter published in Clinical and Translational Allergy.
In a prospective observational study, Dong Liu, of the department of allergy at Beijing Tongren Hospital, and colleagues included 61 patients (62.3% male; median age, 31 years; age range, 16-37 years) with a confirmed allergic rhinitis diagnosis and a major house dust mite allergy.
These patients received standard subcutaneous immunotherapy treatment with Dermatophagoides pteronyssinus (Der p; Alutard SQ, ALK) between July 2017 and July 2019 at Beijing Tongren Hospital.
The immunotherapy program began with 8 weeks of up-dosing followed by maintenance doses administered every 6 weeks (± 2 weeks) for 3 years. At baseline, the researchers measured serum total IgE and house dust mite specific IgE levels.
The researchers calculated each patient’s total nasal symptom score (TNSS), which included scores for congestion, rhinorrhea, sneezing and itching, and daily medication score (DMS) at baseline, 8 weeks, 6 months, and 1, 2 and 3 years.
At each timepoint, they added the TNSS and DMS to determine the average total combined score (ATSC). Researchers determined the immunotherapy’s efficacy by calculating the changes in ATSC between baseline and each timepoint.
After 8 weeks, patients already experienced improvements in individual nasal symptom scores except for sneezing, as well as in in their TNSS and ATCS.
The researchers also found significant correlations between improvements at 3 years and improvements at 8 weeks (r = 0.39; P < .01), 6 months (r = 0.45; P < .001), 1 year (r = 0.41; P < .001) and 2 years (r = 0.48; P < .0001).
At 3 years, the researchers categorized 35 patients (57.4%) with a high response to treatment, classified as a 40% or greater decrease in response, and 26 patients (42.6%) with low or no response, classified as decreases in response that were less than 40%.
Median baseline ATCS included 10 for the high responders and 8 for the low and no responders. Also, 68.6% of the high responders and 50% of the low responders were sensitized to pure house dust mite.
The researchers noted statistically significant differences in the improvements in ATSC experienced by the high response group and the low and no response group between 6 months and 3 years (P < .05).
Analysis also found that the changes in ATSC at 6 months (area under the curve [AUC], 0.7; P = .007), 1 year (AUC, 0.69; P = .012) and 2 years (AUC = 0.69; P = .01) significantly predicted what the clinical response to therapy would be at 3 years.
Additionally, the researchers suggested that higher percentages of mono-sensitized patients and higher TNSS and ATCS composite scores may contribute to treatment outcomes, although these contributions are not significant.
With improvements in ATCS at 6 months and 1 and 2 years indicating final clinical response at 3 years, the researchers said, providers should monitor the short-term efficacy of immunotherapy to identify clinical response and guide individualized treatment.
Perspective
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Michael S. Blaiss, MD, FACAAI, FAAAAI
This is an interesting study, as we do need a way through biomarkers or some other means to know which patients are going to benefit from allergen immunotherapy.
Unfortunately, there are many gaps in this study. Among the low and no responders, we do not know if other allergens contributed to their symptoms more than the house dust mite did, which would explain the results. I also was surprised by how quick the responses were, but we do not know about the allergen schedules for these patients, which could make a difference as well. Additionally, there was no mention of allergy medications, which could influence the results too. Lastly, I was surprised that there were no dropouts in this study, because that is not our experience in the United States.
In my experience, improvements usually take longer with the buildup of house dust mite subcutaneous immunotherapy. We also see a dropout rate. Additionally, most patients need medication at the start of immunotherapy, as there is not an immediate benefit.
Considering the gaps presented in this study, I am not sure we can use this information in judging possible outcomes of house dust immunotherapy in our patients in the US. Next, the researchers should conduct a double-blind, placebo-controlled study that controls for allergy medication with patients that have a clear history of symptoms to house dust mite to see if there is truly a signal related to early improvement in symptoms for responders vs. non-responders.
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