Sublingual immunotherapy

Clinical considerations in the use of sublingual immunotherapy for allergic rhinitis

BACKGROUND

Allergen immunotherapy (AIT) has been in practice for more than 100 years. However, research in novel routes and delivery methods of immunotherapy to treat allergic rhinitis (AR) and conjunctivitis has only recently occurred in the United States, where the predominant form of AIT provided is largely via a subcutaneous immunotherapy (SCIT) route. AIT may prevent new sensitizations, improve symptoms, decrease medication usage, and prevent allergic asthma. Although AIT is the only potentially curative treatment for AR, access and adherence continue to be problematic. Only a fraction of eligible patients actually undergo treatment, and attrition rates are high. An obvious limitation of SCIT includes the requirement of regular injections to be provided in the physician's office due to the potential for anaphylaxis. Sublingual immunotherapy (SLIT) for home administration has been investigated as a potential alternative to address this limitation of SCIT.

METHODS

A literature review was performed including the current findings from randomized clinical trials and meta-analyses with a discussion of the most recent evidence for the efficacy, safety, and dosing of allergen SLIT.

RESULTS

The current data suggest that SLIT is effective for treatment of seasonal allergies, can potentially prevent asthma, and has a favorable safety profile. Head-to-head studies, however, are few, and comparative effectiveness still remains to be answered. Optimal treatment algorithms for SLIT have not yet been established, with wide variation in dosage selection and schedules. Similarly to SCIT, only a few allergens such as ragweed and grass pollen have been found to be effective in large clinical trials.

CONCLUSION

Recent data indicate that SLIT is an effective treatment modality for seasonal AR, improve quality of life, and can potentially prevent asthma but head-to head studies comparing SLIT to SCIT are needed.

Novel approaches to food allergy

Food allergies have increased in recent decades. However, they cannot be effectively treated by the current management, which is limited to the identification and avoidance of foods that induce allergies and to the use of medicines for symptoms relief. To meet the medical need of prevention and cure of food allergies, several therapeutic strategies are under investigation. Some newly developed biologics such as anti-IgE antibody and anti-interleukin (IL)-5 antibody directed against significant molecules in the allergic process have shown their potential for the treatment of food allergies. Allergen-specific immunotherapy is the therapy that induces immune tolerance and may reduce the need for conventional medication, severity of allergic symptoms and eliminate hypersensitivity. In this article, clinical studies of immunotherapy via subcutaneous, oral, sublingual, and epicutaneous routes are extensively reviewed for their safety and effectiveness on various food allergies. In addition, to reduce the risk of anaphylaxis and increase toleragenic immunity, many studies are focusing on the modification of traditional allergens used for immunotherapy. Moreover, a Chinese herbal formulation with potential anti-allergic effects is being evaluated for its efficacy in patients with peanut allergy. Although more studies are needed, accumulated data of current studies represent compelling evidence of curative effects of some strategies and give a hope that food allergies are likely to be successfully treated in the future.

High-dose sublingual immunotherapy in patients with uncontrolled allergic rhinitis sensitized to pollen: a real-life clinical study

BACKGROUND

High-dose pollen sublingual immunotherapy (SLIT) is indicated in patients with moderate to severe allergic rhinitis (AR), especially those who are unable to control their disease with pharmacotherapy. We explore the use of high-dose SLIT in patients with severe AR and sensitized to pollen, in real-life clinical practice. We also analyzed the effect on asthma.

METHODS

This was a prospective observational study conducted at the Allergy outpatient clinic at Hotel Dieu de France Hospital (HDF), Beirut, Lebanon. The cohort, composed of 118 patients between 7 and 55 years old, was regularly evaluated at inclusion, at 12 months, and at 36 months. Fifty-five percent of AR patients had associated controlled asthma. Patients received a standardized pollen extract (Staloral 300IR). The pollen combination was 1 to 3 pollens, the most commonly used were Parietaria judaica, Cupressaceae, 5 grasses, and Oleaceae. In a previous study, those were the main allergenic pollens correlated to AR in the same population. Global assessment of the effect of SLIT was measured using a rhinitis total symptom score (RTSS), a rhinitis medication consumption score (RMCS), a global asthma score (ASS), and an asthma medication consumption score (AMCS).

RESULTS

Using a t test we found that the average scores at inclusion, 12 months, and 36 months, respectively, were as follows: RTSS: 31.32, 16.39 (p < 0.041), and 13.35 (p < 0.041); RMCS: 6.96, 1.96 (p < 0.0162), and 1.61 (p < 0.0162); ASS: 4.62, 1.96 (p < 0.0005), and 1.33 (p < 0.0005); and AMCS: 2.35, 0.78 (p < 0.0005), and 0.7 (p < 0.0005).

CONCLUSION

Our study showed favorable results of SLIT to aeroallergens in patients with uncontrolled AR. The effect is also applicable to the subgroup of patients suffering from concomitant, controlled asthma.

Efficacy of sublingual immunotherapy for allergic asthma: retrospective meta-analysis of randomized, double-blind and placebo-controlled trials

BACKGROUND

Allergen-specific immunotherapy (SIT) is the only available curative choice with a disease-modifying effect against respiratory allergies. The efficacy of SIT via the sublingual route was demonstrated by a number of clinical trials. This meta-analysis was performed to investigate the clinical efficacy and safety of sublingual-specific immunotherapy (SLIT) for allergic asthma.

METHODS

PubMed, EMBASE and the Cochrane Central Register of Controlled Trials were searched for randomized, double-blind and placebo-controlled (DBPC) trials evaluating the efficacy and safety of SLIT on allergic asthma. Subgroup analyses were performed according to age, type of allergen and duration of SLIT treatment.

RESULTS

Sixteen randomized DBPC trials comprising 794 patients in total met the inclusion criteria. The results suggest that SLIT significantly reduces both symptom [standardized mean difference (SMD), -0.74; P=0.006] and medication scores (SMD, -0.78; P=0.02) compared with placebo. SLIT offers a better clinical response in mite sensitive asthmatics but without confirmed proof from subgroup analyses. Prolonged duration of treatment for more than 12 months brings no additive effects. Improvement in the skin prick test was also observed following immunotherapy. There was no consistent effect on forced expiratory volume in 1 s, serum levels of antigen-specific immunoglobulin G4 and immunoglobulin E in the treated group. The risk of adverse effects was relative risk 2.23 (P=0.01).

CONCLUSIONS

SLIT is safe and clinically effective in reducing symptoms and medication use for allergic asthma. Our subgroup analyses failed to identify a disproportionate benefit of SLIT in any specific group of asthmatics, but some possible trends did emerge.