Review of allergy-specific immunotherapy in children with asthma

Treatment with subcutaneous immunotherapy may reduce long-term use of asthma medications in children with allergic asthma, according to a recent systematic review published in Pediatrics. The National Heart, Lung, and Blood Institute identified the importance of this updated systematic review in preparation for an update to asthma management guidelines.

In 2015, about half of all asthma in children in the US was secondary to atopy; most children with allergic asthma were polysensitized. One treatment option is allergen immunotherapy (AIT) to induce allergen-specific immune tolerance. AIT can be administered via subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT).

“Our objective in this review is to provide an update to our previous 2013 systematic review…and summarize the current evidence for the efficacy (symptoms, quality of life [QoL], medication use, health care use, and lung function) and safety of SCIT and SLIT, specifically in pediatric allergic asthma,” wrote Jessica L. Rice, DO, MHS, Department of Pediatrics, Pediatric Pulmonology, Johns Hopkins University School of Medicine, Baltimore, Maryland, and co-authors.

The authors included studies involving children ≤18 years of age in which researchers examined pre-specified outcomes. To be included, trials needed to have an intervention arm receiving SCIT or SLIT (tablet or aqueous).

Researchers excluded studies with the following characteristics: food allergies, aeroallergens not related to asthma, or unspecified allergen type. The authors also excluded studies in which researchers did not report data separately for participants with asthma.

In total, the authors included 40 studies: 17 SCIT trials, 11 SLIT trials, 8 non-randomized controlled trials for SCIT safety, and 4 non-randomized controlled trials for SLIT safety. They included randomized-controlled trials to determine efficacy, and randomized-controlled trials, case series, observational studies, and case reports to evaluate safety. Two reviewers extracted data for this review.

The researchers were only able to synthesize the data in a qualitative—not quantitative—fashion, because the trials represented in this review differed in patient and intervention characteristics.

“The strength of evidence (SOE) was graded for each outcome as specified in our protocol,” wrote the authors. “We used the grading scheme recommended in the Evidence-based Practice Center Methods Guide.”

The following are SOE findings reflecting the efficacy of SCIT:

• Moderate SOE:
  • Decreases long-term use of medications
• Low SOE:
  • Improves quality of life
  • Improves short-term use of medications
  • Decreases systematic steroid use
  • Improves FEV1
• Insufficient evidence:
  • Has effect on asthma symptoms
  • Increases health-care visits

The following are SOE findings reflecting the efficacy of SLIT:

• Low SOE:
  • No effect on use of quick-relief asthma medications
  • No effect on long-term asthma medication use
  • Improves FEV1
• Insufficient evidence:
  • Reduces consumption of systemic corticosteroids
  • Has effect on asthma symptoms
  • Improves quality of life
  • Increases health-care visits

The researchers stated that local and systemic reactions to SCIT and SLIT occurred more frequently in the treatment groups than in the comparator groups.

“In children with allergic asthma,” wrote the researchers, “SCIT may reduce the need for asthma medication, improve FEV1, and improve asthma-related QoL. SLIT may improve FEV1, but does not seem to improve asthma medication use. Local and systemic allergic reactions to SCIT and SLIT are common. Life-threatening events such as anaphylaxis and death were reported rarely.”

Finally, the researchers caution that patients with severe, uncontrolled asthma are at higher risk for systemic reactions; thus, AIT should only be started in these patients when asthma symptoms are stable.

To read more about this study, click here.