HOUSTON – Sublingual immunotherapy, or SLIT, long used by clinicians worldwide, is newly approved for use in the United States, and practice guidelines have yet to be published for U.S. clinicians.
A joint task force of the American Academy of Allergy, Asthma, and Immunology (AAAAI) and the American College of Allergy, Asthma, and Immunology (ACAAI) is drafting the guidelines. While clinicians wait, here is a look at the evidence for efficacy and safety of SLIT – particularly when compared with subcutaneous immunotherapy – as well as at the progress of the guidelines, offered by Dr. Linda Cox, an allergist in private practice in Fort Lauderdale, Fla. Dr. Cox spoke at the annual meeting of the AAAAI.
Dr. Linda Cox
The guidelines will closely follow package labeling for the three sublingual pollen-allergy medications approved last year by the Food and Drug Administration, Dr. Cox said. These are the multipollen allergen tablet Oralair (Stallergenes), the Timothy grass pollen tablet Grastek (Merck), and the ragweed tablet Ragwitek (Merck). The medicines’ indications differ in terms of minimum age for prescription, ranging from 5 to 18 years, and the timing of treatment, with Grastek indicated as a year-round treatment, and the others as seasonal treatments.
FDA labeling on all three medications recommends coprescription of epinephrine pens in case of systemic reactions, and Dr. Cox said that the AAAAI/ACAAI guidelines would reflect this. Nonetheless, coprescription of epi pens “has never been the standard in Europe or other parts of the globe. We don’t have guidance from the broader community in terms of when to take the epinephrine in terms of a SLIT reaction,” she noted. Physicians should “be aware and think about what sort of instructions you’re going to give your patients” on the use of epi pens.
The guidelines in progress advise physicians to counsel patients that site application symptoms such as itching and swelling are very common during the first week of SLIT treatment, and that the majority of SLIT reactions are local (oral, pharyngeal, or abdominal). These local reactions usually disappear within days to weeks without treatment or dose modification, though some can be severe or bothersome enough to discontinue treatment. Systemic allergic reactions are very uncommon.
The guidelines are also likely to caution physicians that there are insufficient studies comparing SLIT and subcutaneous immunotherapy, or SCIT, to make a definitive statement about efficacy, Dr. Cox said. They will note that available studies suggest SCIT is more effective in the first year of treatment than SLIT, and comparative long-term efficacy studies have not been conducted, she added.
Finally, the guidelines are likely to caution that SLIT is contraindicated in patients who are not likely to survive a systemic adverse reaction or the resultant treatment.
Dr. Cox did not say when the guidelines were likely to be published, just that “we are frantically trying to get this document together,” noting the short time that SLIT has been commercially available in the United States.
At the same session on SLIT, Dr. Desiree Larenas Linneman, an allergist in private practice in Mexico City, spoke at the meeting about practical concerns related to SLIT and how to choose whether a patient is better suited to shots or sublingual therapy.
“When you bring sublingual to the public there are several issues you are going to have to be very careful with,” Dr. Larenas Linneman said. Among these are prescriptions of highly concentrated medications by nonallergists, adherence, and patient preference. “And we still do not have data for SLIT on a vast array of comorbidities,” she said.
“When we only had SCIT, these patients came into our offices and the only decision was, would we go for shots or not?” Now the choices are more complicated. A multiallergic 8-year-old, ordinarily a good candidate for SCIT, might be better treated with tablets if the parent is adamant that the child not get shots, she said. An adult who travels constantly for work might find tablets more convenient.
But for multiallergic and highly allergic patients, SCIT is generally the more flexible and reliable option, Dr. Larenas Linneman said. Allergists have access to a great variety of different allergens they can combine to make SCIT, while the approved tablets cover only pollen. And a tablet is a fixed dose, she said, “so there’s no adjustment for highly allergic patients.”
Dr. Larenas Linneman noted that adherence and patient preference are closely related, something that physicians must keep in mind when choosing the form of immunotherapy to offer. “Adherence is a very important issue because we know adherence is quite poor both with SLIT and SCIT,” she said.