Current Evidence on Safety and Practical Considerations for Administration of Sublingual Allergen Immunotherapy (SLIT) in the United States.

Liquid sublingual allergen immunotherapy (SLIT) has been used off-label for decades, and Food and Drug Administration (FDA)-approved grass and ragweed SLIT tablets have been available in the United States since 2014. Potentially life-threatening events from SLIT do occur, although they appear to be very rare, especially for FDA-approved products. Practice guidelines that incorporate safety precautions regarding the use of SLIT in the United States are needed. This clinical commentary attempts to address unresolved issues including controversy regarding the FDA mandate for the prescription of epinephrine autoinjectors for patients on SLIT; how to approach polysensitized patients; optimal timing and duration of SLIT administration; how to address gaps in therapy; whether antihistamines can prevent local reactions, if certain patient populations (such as persistent asthmatics) should not receive SLIT; and when to instruct patients to self-administer epinephrine. Key points are that physicians should focus on educating patients regarding: (1) when not to administer SLIT; (2) how to recognize a potentially serious allergic reaction to SLIT; and (3) when to administer epinephrine and seek emergency care.

Risk factors for fatal and nonfatal reactions to subcutaneous immunotherapy: National surveillance study on allergen immunotherapy (2008-2013).

BACKGROUND: In 2008, an annual surveillance study of systemic reactions (SRs) from subcutaneous immunotherapy (SCIT) injections was initiated in North America. OBJECTIVE: To define the incidence of SRs to SCIT. METHODS: From 2008 to 2013, 27% to 51% of American Academy of Allergy, Asthma, and Immunology and American College of Asthma, Allergy, and Immunology members completed an annual survey of SCIT-related SRs of varying severity. From 2012 to 2013, data were collected regarding SRs with off-label sublingual immunotherapy (SLIT), selection of patients with asthma for SCIT, and strategies for dose adjustment during pollen seasons. RESULTS: From 2008 to 2013, data were gathered on 28.9 million injection visits, including 344,480 patients for 2012 to 2013. Since 2008, a total of 2 confirmed fatalities were directly reported that occurred under the care of allergists. Two additional fatalities occurred under the care of nonallergists. The rate of SRs from SCIT remained stable, occurring in 1.9% of patients, with 0.08% and 0.02% experiencing grade 3 and 4 SRs. SRs occurred in 1.4% of patients receiving off-label SLIT, including 0.03% with grade 3 SRs. There were no SLIT-related grade 4 SRs or fatalities. Practices that never administered SCIT in patients with uncontrolled asthma (Asthma Control Test score <20) had significantly fewer grade 3 and 4 SRs (odds ratio, 0.7; 95% confidence interval, 0.5-1.0, and odds ratio, 0.3; 95% confidence interval, 0.1-0.8, respectively). Lowering doses during pollen seasons for patients with highly positive skin tests reduced SRs of all severity grades (P < .05). CONCLUSIONS: SCIT-related fatality rates may be decreasing, but continued vigilance regarding modifiable risk factors, including careful patient selection, is needed. Dose adjustment during pollen seasons for highly sensitive patients may reduce risks. Potential risk for SRs from off-label SLIT exists.

Immunotherapy safety: what have we learned from surveillance surveys?

Subcutaneous allergen immunotherapy (SCIT) is beneficial for the treatment of allergic rhinitis, asthma, and in preventing stinging insect anaphylaxis, but is not without risks. Four retrospective surveillance surveys and one on-going national prospective study have attempted to characterize the incidence and risk factors for fatal and non-fatal SCIT reactions. These studies have contributed significantly to currently recommended SCIT safety guidelines. Recent surveillance studies indicate stable SR rates, and a possible decline in the incidence of fatal reactions since the implementation of evidence-based safety guidelines. This review will provide a detailed summary of the evidence from surveillance studies for risk factors associated with SCIT reactions, including: uncontrolled asthma, prior systemic reactions, dosing during peak pollen seasons, epinephrine being delayed or not given, dosing or administration errors, inadequate waiting times, reactions occurring more than 30 min after injections, injections given in medically unsupervised settings, concomitant beta-blocker and angiotensin-converting enzyme inhibitor (ACEi) use, and accelerated build-up regimens.