Subcutaneous immuntherapy (SCIT or “allergy shots”) has been utilized for decades as a safe and effective treatment for allergic asthma, allergic rhinitis, hymenoptera hypersensitivity, and allergic conjunctivitis. Multiple well designed trials have demonstrated that SCIT is a disease-modifying treatment for allergies and asthma with reduction in medication use, lower symptom frequency and severity, reduction in exacerbation rates, less development of new allergies, and improvement in lung function and quality of life. Financial analyses have documented cost effectiveness, with reduction in overall healthcare utilization for appropriately diagnosed and treated SCIT patients; which has led to widespread coverage by all major payers including Medicare and Oregon Health Plan.
Sublingual immunotherapy (SLIT, allergen delivered orally) has been shown to be safe and effective WHEN DOSED APPROPRIATELY using standardized allergen preparations. This treatment has been available in Europe for several years for select allergens such as house dust mite, parietaria (a weed pollen) and northern pasture grass. Most studies evaluating safety and efficacy of SLIT involve only one or few allergens delivered to monosensitized or oligosensitized (without multiple allergies) individuals. These studies have delivered a strong safety signal, with very few anaphylactic events even when dosing was performed at home by the patient. Oral itching and gastrointestinal problems were frequent but generally mild adverse events which generally waned with time.
Our research site in Medford has been involved in sublingual immunotherapy studies for grass and house dust mite. Though we are blinded to the treatment allocation for each of our patients, we have reviewed the overall data and agree that this form of immunotherapy is likely beneficial for appropriate patients.
In December 2013, an FDA advisory committee recommended approval of a grass pollen tablet which will be marketed jointly by 2 US companies, likely beginning spring of 2014. In January 2014, the same committee recommended approval of a ragweed allergen tablet which will also be marketed by a US pharmaceutical company if approved. Although the FDA is not obligated to follow the recommendations of its advisory committees, we usually observe that the agency does.
One of these 2 products will be very relevant in the Rogue Valley. We are a “node” of high density northern grass pollen during late spring/early summer. Very few geographic areas of the US experience grass pollen as intense and predictable as the Rogue Valley. The Willamette Valley may be a bit worse, but we have a huge grass season! Patients who are PRIMARILY SENSITIZED to grass pollen will be good candidates for grass SLIT if other criteria support this treatment option. Because treatment with SLIT for grass will not alter other allergies, we recommend that skin testing to inhalant allergens be performed prior to beginning SLIT to identify the optimal treatment program for each individual. Because we have experience with this product in the context of the US clinical trials, we will be prepared to use these new modalities when they become available (likely soon). Board-certified allergists are trained allergy specialists who are equipped to help you evaluate all treatment options. We caution against testing to only grass pollen prior to making this treatment decision; grass is certainly important, though we frequently find that grass allergic patients improve most if they avoid and treat additional relevant allergens based on their personal profile.
Ragweed is not relevant in the Rogue Valley. The distribution of giant and short ragweed in the US spares our region. We have performed pollen counts using a Rotorod sampler in our Medford office each spring and summer for many years. We’ve never seen a ragweed pollen grain. The ragweed product will be very relevant for patients from the Intermountain West to the East Coast, with greatest concentration in the Midwest.
House dust mite SLIT is still under evaluation by industry partners. The FDA will evaluate this product in the future.
We welcome questions about SLIT. At AAC, we adhere to evidence-based medicine and strive to personalize each treatment plan based on the individual’s goals and style. We are excited to broaden the treatment of allergies using SLIT where appropriate.
Kevin Parks MD