Immunotherapy: What lies beyond

Allergen immunotherapy has been used to treat allergic diseases, such as asthma, allergic rhinitis, and venom allergy, since first described over a century ago. The current standard of care in the United States involves subcutaneous administration of clinically relevant allergens for several months, building up to eventual monthly injections for typically 3 to 5 years. Recent advances have improved the safety and efficacy of immunotherapy. The addition of omalizumab or Toll-like receptor agonists to standard subcutaneous immunotherapy has proved beneficial. Altering the extract itself, either through chemical manipulation producing allergoids or directly producing recombinant proteins or significant peptides, has been evaluated with promising results. The use of different administration techniques, such as sublingual immunotherapy, is common in Europe and is on the immediate horizon in the United States. Other methods of administering allergen immunotherapy have been studied, including epicutaneous, intralymphatic, intranasal, and oral immunotherapy. In this review we focus on new types and routes of immunotherapy, exploring recent human clinical trial data. The promise of better immunotherapies appears closer than ever before, but much work is still needed to develop novel immunotherapies that induce immunologic tolerance and enhanced clinical efficacy and safety over that noted for subcutaneous allergen immunotherapy.