Impact of Adverse Event Solicitation on the Safety Profile of SQ House Dust Mite Sublingual Immunotherapy Tablet.

Background: It has been recommended that sublingual immunotherapy (SLIT) safety be assessed using solicited adverse event (AE) collection methods.

Objectives: The objectives of this study were to describe the impact on the safety profile of SQ house dust mite (HDM) SLIT-tablet (12 SQ-HDM dose) when prespecified local application site reactions were solicited versus unsolicited, and discuss ramifications of AE solicitation.

Methods: Subjects were randomized to daily 12 SQ-HDM or placebo for up to 52 weeks in 4 double-blinded, multicenter trials. In one trial (NCT01700192; N = 1272), subjects documented daily the presence or absence of 15 World Allergy Organization-defined local application site reactions using a structured questionnaire of closed-ended questions (solicited AEs). Subjects in the other trials were not asked about specific AEs (unsolicited AEs), and AE data were pooled (N = 1287). Analysis was limited to adults aged 18 to 65 years.

Results: Whether AEs were solicited or unsolicited, the most common AEs leading to study discontinuation with 12 SQ-HDM were throat irritation and oral pruritus. Approximately 95% of treatment-related AEs were mild to moderate. Placebo-subtracted frequencies of local application site reactions associated with 12 SQ-HDM were higher when solicited versus unsolicited (ie, throat irritation, 46% vs 13%, respectively; oral pruritus, 47% vs 17%; ear pruritus, 40% vs 4%; mouth swelling, 8% vs 2%; tongue ulceration, 10% vs 0%; mouth ulceration, 7% vs <1%).

Conclusions: Qualitatively, the safety profile of 12 SQ-HDM was similar when AEs were solicited versus unsolicited; hence, solicitation did not alter the safety profile. Higher observed frequencies of local application site reactions with AE solicitation may be partly due to suggestive reporting bias, as observed in placebo-treated subjects.