Will Sublingual Immunotherapy Become an Approved Treatment Method in the United States?

Excerpt

During the past 6 years, there has been a surge of interest in sublingual immunotherapy (SLIT) in the United States correlating with its growing use in Europe and other parts of the world. A position paper on SLIT was developed by the World Allergy Organization with the involvement of the American Academy of Allergy, Asthma, and Immunology; American College of Allergy, Asthma, and Immunology; and many other regional, national, and international organizations. With multiple large studies demonstrating the efficacy of SLIT, the question had been when will SLIT come to the United States? Now, after several “failed” US clinical trials, the question has evolved into will SLIT (ever) become an approved product in the United States? In some respects, the answer to the former question is that some variant of SLIT has been present in the United States for years, generally as low-dose SLIT prescribed by non–allergy/immunology-trained practitioners as part of unproven treatment regimens such as neutralization/provocation or homeopathy. Only a small percentage of allergists currently prescribe SLIT (~ 6%), according to two surveys conducted in early-2007 and late-2009 (by members of the American College of Allergy, Asthma, and Immunology and Joint Council of Allergy and Asthma and Immunology, respectively). Lack of a US Food and Drug Administration (FDA)-approved SLIT formulation was cited as the most common reason for not prescribing SLIT in these two surveys, followed by “effective dose not known.” However, a significant percentage of the 828 respondents in the 2007 survey indicated that if there was an FDA-approved SLIT formulation, they would prescribe it for allergic rhinitis (65.7%), mild asthma (49.5%), moderate/severe asthma (40.5%), and in children younger than 5 years of age (45.5%). Only 13.5% of the respondents indicated that they would not be willing to prescribe SLIT. Of note, only 67.4% of the survey’s respondents prescribed subcutaneous immunotherapy (SCIT). In the survey conducted 2 years later, 64.2% of the 472 respondents answered no to the following question: “Do you believe there is sufficient evidence to say that SLIT-based immunotherapy is evidence based?” The 2009 survey results may represent a change in US allergists’ perspective on SLIT compared with the earlier survey, or they may just reflect variations resulting from the different survey populations and designs. However, the interest and enthusiasm for SLIT that likely began in 2004 when the first clinical trial intended to seek FDA approval for SLIT products was announced in a Greer press release may have waned because no product has obtained such approval to date, 6 years later. …