Allergen immunotherapy, frequently known as allergy shots, have a substantial amount of research showing that they are effective in treating allergies and allergic asthma and can be curative. However, they can be inconvenient since they must be given in a medical facility rather than at home because of the risk of allergic reactions; although this risk is very low. In addition, a patient on allergy shots has to receive a shot that can sometimes be uncomfortable. Because of these reasons, a different form of allergen immunotherapy called SubLingual ImmunoTherapy, commonly referred to as SLIT, in which allergen is placed underneath the tongue has been an attractive alternative.
SLIT is probably most commonly thought of as “allergy drops under the tongue” by many here in the U.S., however most of the data showing clinical effectiveness is using Sublingual Tablet ImmunoTherapy (sometimes referred to as STIT or also SLIT-tablet) to certain types of grass pollen. Over the past 10 years there has been much more research performed with SLIT grass tablets that have shown to be clinically effective and provide lasting relief. In addition, research has also shown SLIT to be safe for home use making it much more convenient. Nonetheless, there has never been an FDA(Food and Drug Administration) approved form of SLIT here in the U.S., and currently all “allergy drops” are provided “off-label.”
Because of this emerging data, very recently on December 11th, 2013, an allergenic products subdivision of the FDA voted for the approval of two different types of grass tablets. The final approval of the FDA is pending, but it is likely that these two products will be approved. These two “grass allergy” tablets will be particularly attractive for children who are usually afraid of receiving shots and for others who are unable to visit their allergist’s office regularly for allergy shots. Although SLIT tablets will be probably be considered safe for home use, the prescribing instructions for both products will likely recommend that patient’s carry an autoinjectable epinephrine device such as an EpiPen, which is frequently recommended for patients receiving allergy shots.
It is important to note that the only type of allergen in these tablets is grass, and therefore will not benefit those who are not allergic to grass. Also, most of the research was performed on patients with an allergy to grass only and not to any other pollens, dust mite, pets or mold. There is not much data on whether it will be beneficial for those who are allergic to other pollens and it certainly makes sense that it would not provide relief for those who are allergic to more year-round indoor allergens such as dust mite, cat or dog. Most patients with allergic disease here in the U.S. are allergic to multiple allergens.
“Off-label” use of SLIT allergy drops under the tongue is sometimes prescribed for patients currently using allergen extract designed for allergy shots. There have been a few studies particularly with ragweed and fewer with dust mite, but the results were disappointing. There have been almost no research regarding multiple allergy SLIT, which is the current off-label use of allergy drops in the U.S. Lastly, data shows that allergy shots are more effective than SLIT and can be tailored to all allergens that someone is allergic to.
So are allergy drops and tablets finally here now? Well, yes and no. Yes, given the likely approval of grass allergy tablets in the near future from the FDA, and yes given that off-label use of SLIT allergy drops are being utilized more commonly. But No, due to multiple questions that are still yet to be answered such as: effective doses for each allergen, effectiveness for those who are allergic to multiple allergens, and appropriate instructions for missed doses, and many others.
The best news is that approval and use of these SLIT tablets will further spark research to be performed on other allergens and for “allergy drops” to develop better understanding of effective doses, protocols and safety in the future.
By Rodney Johnson, MD, Atlanta ENT