Sublingual Immunotherapy (SLIT)

Introduction

Immunotherapy has gained worldwide acceptance as a treatment option for allergic diseases since it was first introduced in 1911.¹ The initial route of administration of immunotherapy was via the subcutaneous route (SCIT). In the past century other modes of administration have been investigated to improve patient safety and comfort. Oral immunotherapy was first proposed in the early 1900s.² During the 1950s, local bronchial desensitization was suggested and investigated,^{4, 5} whereas sublingual immunotherapy (SLIT) appeared in 1986.⁶ That same year 26 deaths caused by SCIT were reported by the British Committee for the Safety of Medicines⁷ and raised serious concerns about the safety and the risk-benefit ratio of SCIT. This prompted the search for safer and more convenient modalities of immunotherapy.

Abstract

Sublingual immunotherapy (SLIT) is raising a lot of interest as a safer way to administer immunotherapy and is considered standard of care in many countries in Europe. It is, however, still a somewhat controversial treatment in the United States, where it is not yet approved by the FDA. Several double-blind, placebo-controlled randomized trials have been undertaken to establish the safety, dosing regimen and treatment duration of SLIT, which have demonstrated good therapeutic effects and safety profile. This paper reviews efficacy and safety data for SLIT, discusses methodological issues for appropriate SLIT trials, and proposes how to best apply the data in clinical practice.

Keywords

Immunotherapy, SCIT, SLIT