Sublingual Immunotherapy: Effective Allergy Treatment, Time-Saving Intervention

For over 100 years, individuals with allergic rhinoconjunctivitis and asthma who needed more than temporary symptomatic treatment have sought out allergy shots.^1,2 Clinician-administered subcutaneous immunotherapy (SCIT) injections contain very small doses of a patient’s specific allergens and are tailored based on sensitivity and response. Patients receive these injections in 3 phases: (1) once or twice a week for a few months, (2) twice a month for several months, and (3) monthly for at least 3 years. After each injection, patients are medically supervised for 20 to 30 minutes^3,4 and can often tolerate more than 100 times their pretreatment allergen exposure.²

Although SCITs are still available and prescribed, sublingual immunotherapy (SLIT) offers an alternative. The American Academy of Otolaryngology-Head and Neck Surgery Foundation clinical practice guideline for allergic rhinitis (AR) recommends SLIT for patients with inadequate response to antihistamines and nasal corticosteroids.⁵ SLIT offers the following advantages: self-administration, oral (noninvasive) administration, and lower anaphylaxis risk. In general, allergists consider SLIT safer than SCIT.⁵ Globally, SLIT also is popular. The World Health Organization has endorsed SLIT as a practical alternative to injection therapy.⁶

Other countries have used SLIT for more than 60 years. Since 2014, the FDA has approved 3 SLIT products (Table 1^7-9) for AR due to specific allergens.^7-9 Similar to SCIT, SLIT provides gradually increasing doses of FDA-approved antigens to bolster the body’s tolerance to allergens over a much shorter period of time than SCIT requires.

Best Candidates? Worst Candidates? Educated Candidates?

Many individuals do not tolerate allergy shots, some patients find them frightening or painful, and others cannot get the time away from work or school to see a health care provider for frequent shots. Patients tend to be more adherent to SLIT because they can self-administer the doses.¹⁰ Some patients, however, are poor candidates for SLIT (Table 2^5,7-9).

Patients who use SLIT require targeted counseling. They need to know that unlike antihistamines, SLIT will not relieve allergy symptoms immediately. Life-threatening allergic reactions (eg, anaphylaxis and severe laryngopharyngeal restriction) are still possible, which is why the first dose is followed by 30 minutes of medical observation.^7-9 When patients receive SLIT prescriptions, it is prudent to have companion prescriptions for auto-injectable epinephrine. Therefore, pharmacists must ensure that patients know the symptoms of anaphylaxis (ie, rapid heartbeat; flushed or itching skin; difficulty breathing, swallowing, or talking; cramping; nausea; vomiting; diarrhea) and are educated, and can demonstrate how to use the auto-injector.^7-9

Patients should only remove the tablet for their SLIT treatment from the blister pack immediately before taking it. They must then place the tablet under their tongue until it completely dissolves and then swallow. After handling the tablet, patients must wash their hands and avoid food or beverages for 5 minutes.^7-9 Adverse effects that include itching or burning of the mouth or lips and, rarely, gastrointestinal symptoms usually resolve within a week.^7-9

Here Comes the Pollen

Patients must track the allergy seasons in their geographic location. Table 3 lists online pollen count/forecast sources. The American Academy of Allergy, Asthma & Immunology bases its tracker on certified pollen counters (specially trained, certified allied health workers who count pollen for 2 hours a day, 3 times a week, under an allergist’s direction).¹¹

End Note

Many insurers employ medical necessity guidelines or prior authorization for SLIT; pharmacists can find them online. For the most part, insurers require patients to undergo necessary testing and have tried all appropriate options before progressing to SLIT.

Researchers continue to investigate better ways to address seasonal allergies, including intralymphatic immunotherapy, epicutaneous immunotherapy, local nasal immunotherapy, oral immunotherapy, and oral mucosal immunotherapy.¹² For now, SLIT is a reasonable, effective option for patients with unresponsive allergies.

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy.

References

• Freeman J. Further observations of the treatment of hay fever by hypodermic inoculations of pollen vaccine. Lancet. 1911;2:814-817.
• Noon L. Prophylactic inoculation against hay fever. Lancet. 1911;1:1572-1573.
• Ross RN, Nelson HS, Finegold I. Effectiveness of specific immunotherapy in the treatment of allergic rhinitis: an analysis of randomized, prospective, single- or double-blind, placebo-controlled studies. Clin Ther. 2000;22(3):342-350.
• Calderón MA, Alves B, Jacobson M, Hurwitz B, Sheikh A, Durham S. Allergen injection immunotherapy for seasonal allergic rhinitis. Cochrane Database Syst Rev. 200724;(1):CD001936.
• Seidman MD, Gurgel RK, Lin SY, et al; Guideline Otolaryngology Development Group. AAO-HNSF. Clinical practice guideline: allergic rhinitis. Otolaryngol Head Neck Surg. 2015;152(suppl 1):S1-S43. doi: 10.1177/0194599814561600.
• Bousquet J, Van Cauwenberge P, Khaltaev N; Aria Workshop Group; World Health Organization. Allergic rhinitis and its impact on asthma. J Allergy Clin Immunol. 2001;108(suppl 5):S147-S334.
• Grastek (Timothy grass pollen allergen extract) [prescribing information]. Whitehouse Station, NJ: Merck Sharp & Dohme Corp; 2016.
• Oralair (sweet vernal, orchard, perennial rye, Timothy, and Kentucky blue grass mixed pollens allergen extract) [prescribing information]. Antony, France: Stallergenes S.A.; 2014.
• Ragwitek (short ragweed pollen allergen extract) [prescribing information]. Whitehouse Station, NJ: Merck Sharp & Dohme Corp; 2016.
• Chester JG, Bremberg MG, Reisacher WR. Patient preferences for route of allergy immunotherapy: a comparison of four delivery methods. Int Forum Allergy Rhinol. 2016;6(5):454-459. doi: 10.1002/alr.21707.
• Burks AW, Calderon MA, Casale T, et al. Update on allergy immunotherapy: American Academy of Allergy, Asthma & Immunology/European Academy of Allergy and Clinical Immunology/PRACTALL consensus report. J Allergy Clin Immunol. 2013;131(5):1288-1296. doi: 10.1016/j.jaci.2013.01.049.
• Aricigil M, Muluk NB, Sakarya EU, et al. New routes of allergen immunotherapy. Am J Rhinol Allergy. 2016;30(6):193-197. doi: 10.2500/ajra.2016.30.4379.