Advances in allergen immunotherapy as a treatment of asthma

ABSTRACT

Introduction: Specific immunotherapy is the only treatment acting on causes and not only on symptoms of respiratory allergy. It was first introduced as subcutaneous immunotherapy (SCIT) with the aim to induce immunological tolerance to the administered allergen(s). In the 1980s, sublingual immunotherapy (SLIT) was developed, mainly to improve the safety, which was a critical issue at that time.

Areas covered: This article reviews the available literature, including a large number of randomized controlled trials, meta-analyses, and real-life studies as well, on the outcomes of SCIT and SLIT concerning the treatment critical issues of the two routes, that are efficacy, safety, cost-effectiveness, and compliance to treatment.

Expert opinion: SCIT and SLIT are similarly effective in treating patients with respiratory allergy, providing, based on the induction of typical changes in the immunologic response, an early control of symptoms that steadily increases during the treatment and, once reached the recommended duration of 3 years, continues to work after stopping. This outcome is the major factor influencing the economic advantage of SCIT and SLIT over drug treatment.

KEYWORDS:

• Allergen immunotherapy
• asthma
• efficacy

Article highlights

• Asthma is a serious health problem with increasing prevalence, affecting patients of all age and causing a significant burden of disease.

• Allergen immunotherapy is the only treatment acting on the causes of allergic asthma and not simply on symptoms.

• Allergen immunotherapy was first introduced as subcutaneous immunotherapy (SCIT), while sublingual immunotherapy (SLIT) was developed in the 1980s, mainly to reduce the risk of adverse reactions.

• Both routes of administration result in a clinical effectiveness on asthma which persists also after treatment withdrawal, provided the recommended duration of at least 3 years is reached.

• The overall data from meta-analyses suggest a higher efficacy for SCIT and a higher safety for SLIT, but the quality of allergen extracts is the crucial issue for effectiveness.

• The results from controlled trials with high quality dust mite SLIT tablets were acknowledged in the GINA guideline as add-on therapy in mite allergic adult patients who have asthma exacerbations despite inhaled corticosteroid treatment.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.