The Prevalence of Eosinophilic Esophagitis with Use of SQ HDM SLIT-tablet

RATIONALE: The SQ house dust mite (HDM) SLIT-tablet is approved in North America for treatment of HDM allergic rhinitis with/without conjunctivitis in adults (ODACTRA^TM, 12 SQ-HDM, ALK, Denmark). Isolated cases of eosinophilic esophagitis (EoE) have been reported with sublingual allergy immunotherapy (SLIT), particularly in food-desensitization trials; therefore EoE is monitored as a potential risk. We present cases of EoE reported with the HDM SLIT-tablet.

METHODS: The clinical and post-marketing databases were searched for any reports of EoE.

RESULTS: In the clinical program (4,175 subjects in active groups), 2 cases of EoE were reported (~48/100.000). One case was reported by a US, adolescent, male subject with a 3-year history of heartburn, dysphasia, and stomach discomfort. EoE (assessed as moderate) was diagnosed with biopsy 6 months after start of treatment with 12 SQ-HDM. Treatment included PPI and fluticasone. A French woman with medical history of gastrointestinal reflux-symptoms reported another case. This case was diagnosed with biopsy 3 months after start of treatment with 6 SQ-HDM. It was assessed as mild, with a possible causal relation to treatment. Treatment included PPI and antacid. Both subjects completed the 1 year of treatment without changes to investigational treatment. In worldwide post-marketing, 3 cases of EoE have been reported with exposure estimated to 20,102 treatment-years (~15/100,000 TY). 2 cases were reported as confirmed with biopsy.

CONCLUSIONS: The background prevalence of EOE is 57/100,000 persons in the US. Thus, the prevalence of EoE with SQ HDM SLIT-tablet does not support a potential risk related to treatment at this point in time.