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Monday, January 4, 2010

“Long-term clinical efficacy in grass pollen rhinoconjunctivitis after treatment with SQ-standardized grass allergy immunotherapy tablet”

The featured article for this first blog is “Long-term clinical efficacy in grass pollen rhinoconjunctivitis after treatment with SQ-standardized grass allergy immunotherapy tablet” (Durham et al. J Allergy Clin Immunol 2009;125:131-138.e7), from our January issue. The authors report, for the first time, long-term benefit associated with sublingual immunotherapy for timothy grass pollen studied in a multisite, randomized, placebo-controlled trial. They describe significant decreases in daily allergy symptoms as well as medication use both during the study and for 1 year after subjects’ participation ended. Durham and colleagues also report progressive changes in specific IgG4 and IgE-blocking factor in subjects receiving active treatment, demonstrating disease modification, which has been previously reported for subcutaneous administration. Because oral administration was associated with only mild, local adverse effects, such as oral pruritis, Durham et al. suggest that patient-administration with prescription is supported by the safety profile.

We asked lead author Stephen R. Durham, MD, to tell us a little more about this paper, and what follow-up studies are needed:

“The results of this multicentre trial confirm long-term efficacy of sublingual grass pollen allergen tablet immunotherapy and its disease modifying potential. It will be of great interest to see whether these long-term benefits are sustained for more than one year following discontinuation. Patients had confirmed IgE-mediated disease and a suboptimal response to usual pharmacotherapy. Although local side effects of itching/swelling in the mouth were common, in general they resolved within 1-2 weeks and were not bothersome and no serious side effects were observed. The data raise the question whether the treatment should be introduced earlier in the course of the disease and in a broader range of patients. As for the subcutaneous route, initial prescription of sublingual immunotherapy should be by a Specialist in Allergy, with observation of the first dose, whereas the treatment is thereafter suitable for home self-administration. Similar studies are required for other allergens and possible preventive effects should be explored in high risk children with sensitisation with/without associated early atopic disease.”

Do you have any questions for the authors, or comments about this study? We want to hear from you. Please feel free to post your own questions or comments. All questions and comments will be forwarded to the authors for a response.

5 comments:

  1. This is an important article and Durham and his colleagues should be congratulated. I look forward to the application of this to other allergens and to the day when our specialty can use this type of approach to broadly treat allergies.

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  2. Robert K. Bush, MD, the JACI Editor for this paper, provided the following comment: "This study is among the first to demonstrate the long-term beneficial effectiveness of sublingual immunotherapy for allergic rhinoconjunctivitis. The convenience of the delivery system is particularly appealing. Large scale trials are warranted in the United States since sublingual immunotherapy may provide similar benefits with less risk than subcutaneous immunotherapy."

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  3. From Harold S. Nelson, MD: "The paper by Durham, et al (JACI 2010;125:131-8) reporting the 4th year results from the ALK-Abello’ grass SLIT study is a welcome addition to the immunotherapy literature. They report that the clinical improvement seen during three years of SLIT continues with “similar efficacy” one year after stopping active therapy. What is most welcome is the indication that there will be another year of follow-up of these subjects. Other studies in which SLIT was given for three years and there was follow-up after stopping therapy have suggested waning of effect after one year (Ott et al, Allergy 2009;64:179-86) and after three years (Tahamiler et al. ORL 2008;70:144-50). In the current article by Durham there is also a small, but consistent fall-off compared to placebo in improvement for symptoms, medication and symptom- and medication-free days from the last year of active therapy to the first year off treatment. Whether this is chance variation or a significant loss of effect should be evident when the 2009 grass pollen season results become available."

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  4. Sten Dreborg, MD, PhDJanuary 10, 2010 at 7:52 AM

    I agree with the positive comments by others.
    I have two comments to this article:
    1. In placebo controlled trials, the difference in change in symptom scores etc. between the active and placebo groups should be compared. The differences at time points, as given in the paper are of less interest. The reason to use placebo is to compare the change over time with as little influence as possible by possible differences between the groups before treatment (0 season).
    2. I appreciate the longstanding effect and your follow up after one year without treatment. However, the degree of improvement is of the greatest importance to the patient. The effect of low dose SLIT is not comparable that of high dose SCIT. As an example, a reduction by 75 % in relation to pretreatment was achieved in the birch/birch-mix trial by Möller et al. Clin Allergy 1986;16: 135 - 143 (not placebo controlled, but blinded comparing two extracts).

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  5. As to Dr Dreborg's comment #2 on the efficacy of IT, I'm surprised how little interest intralymphatic allergen immunotherapy has raised interest (Proc Natl Acad Sci USA 2008; 105:17908). Is it too effective to be interesting?

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