Ask The Expert
September 9, 2013
Role for SCIT
Because of the huge safety profile of SLIT versus SCIT, in terms of both recorded deaths and episodes of anaphylaxis, is there any role at all for SCIT in treating aeroallergen disease in countries where both are available and approved?
From the Editors: This is an interesting and topical question which is often discussed in those parts of the world where both forms of immunotherapy have been available for over 10 years. We appreciate the contribution of our experts.
By Dr. Linda Cox
The answer to the question is: yes. There will be a role for SLIT and SCIT in the treatment of aeroallergen-induced allergic disease in countries where both are available.
Before explaining why I believe this is the case, I would like to address the first part of the question; the safety profile of SLIT versus SCIT. While I agree that SLIT has a more favorable safety profile than SCIT, which allows for home administration, I do not think there is a “huge” safety issue with SCIT when appropriately administered in a supervised medical setting. 1 To the contrary, most surveys and studies suggest the SCIT systemic rate is approximately 0.1 % of injections or 2 to 5 % of patients.2 In the AAAAI/ACAAI immunotherapy safety survey, there were no confirmed fatalities from 2008 to 2011, which included approximately 8 million injection visits per year. Previous AAAAI membership surveys reported SCIT-related fatalities at a rate of 1 in 2 to 2.5 million injections.3 The authors of the most recent AAAAI/ACAAI survey speculated that improved safety measures, especially regarding asthma assessment before SCIT injections, may be factor in the reduced SCIT mortality rate.4
In essence, I believe SCIT and SLIT have comparable safety when they are appropriately administered. Read the entire answer
By Prof. Paul Potter
There is a role for both SCIT and SLIT in all countries for the treatment of aeroallergy. The answer therefore is yes and no.
SCIT still needs to be available for aeroallergens in all regions where allergy is practiced. This is so for several reasons including the fact because there are still no, or very few, validated SLIT vaccines for many aeroallergens – in particular for Cat, Dog, Horse, Fungal, and other specific Tree allergens. In addition, not all vaccine companies registered in some countries have a SLIT vaccine.
SLIT also is not suitable for patients who may not be able to be compliant with daily oral medications for 3 years and who would prefer daily monthly injections. This is particularly the case for adult males who tend to prefer SCIT. Even in developing countries patients are entitled to the option of having SCIT, as it is possibly “more” effective based on some recent comparative meta- analyses for certain allergens. However, in practice, in countries where SLIT has become available in recent years, it has rapidly become the popular choice for Mite and Grass pollen allergies, particularly for children. Since it can be prescribed away from the few major centres in the cities where SCIT could be safely given, in the rural areas it is the ONLY safe and effective option for immunotherapy, and SCIT is not offered for rural patients.
SLIT will eventually become the global popular choice in the future as better and more patient friendly SLIT vaccines such as Sublingual Tablets become available for more allergens.
Paul Potter, MD
Allergy Diagnostic and Clinical Research Unit
University of Cape Town
By Prof Hugo Van Bever
From a limited number of comparative studies between SCIT and SLIT it seems that both treatments have a similar efficacy profile, although conflicting results have been published (See Int Arch Allergy Immunol, 2012, 157, 288). Moreover, it has not been excluded whether or not specific patients will respond better to SCIT, while others to SLIT. Therefore, more studies on the clinical benefit of both treatments, including on cost-effectiveness, are still needed, especially in children. Without doubt, SLIT is more child-friendly and has a better safety profile then SCIT. However, optimal monitoring and safety precautions are still advised, as side effects of SLIT have been reported.
Taken together current evidence it seems that for the majority of patients with aeroallergen disease SLIT is the treatment of choice. Other factors that influence the choice are the vaccine availability or approval (cfr USA), the geographic location, cost, and patient compliance. The fact that a minority of patients might prefer 1 monthly injection over daily sublingual treatment, or vice versa, also influences the choice. A tailored approach in which pros and cons are discussed with each patient / parents seems the best approach, considering that both SCIT and SLIT are equally effective in patients with an aeroallergen disease. Read the entire answer
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