Tolerability of the SQ Tree SLIT Tablet in Adults

The tree pollen sublingual immunotherapy (SLIT)-tablet (ALK, Denmark) is being developed for the treatment of tree pollen induced allergic rhinitis with or without conjunctivitis. The objective of this Phase I trial was to investigate the tolerability and acceptable dose range of the SQ tree SLIT-tablet in adults with allergic rhinoconjunctivitis.

The trial was a randomized, double-blind, placebo-controlled, dose escalation Phase I trial that included 70 adults (aged 19-61 years) with birch pollen-induced rhinoconjunctivitis with or without mild to moderate asthma. The trial included 6 different dosage groups that were randomized 3:1 to active treatment or placebo once daily for 28 days. Adverse events (AEs) were coded in the Medical Dictionary for Regulatory Activities by medically qualified personnel. Immunologic assessments included IgE and IgE-blocking factor.

Most (96%) reported AEs were mild, and only 5 severe events (0.2%) were reported. The most frequently reported investigational medicinal product-related AEs were oral pruritus, ear pruritus, mouth edema, sensation of foreign body, throat irritation, pharyngolaryngeal pain, dry throat, tongue blistering, eye pruritus, and headache. The trial included doses ranging from 1 to 24 development units (DU), and the mean number of investigational medicinal product-related AEs per participant was highest in the 24 DU group. The 12 and 24 DU doses induced statistically significant changes from baseline compared with placebo in birch specific IgE and IgE-blocking factor.

The trial found that doses up to 12 DU of the SQ tree SLIT tablet have a tolerability profile suitable for at-home administration. An immunomodulatory effect was found for all doses included in the trial, and doses up to 12 DU were thus chosen for further clinical development of the SQ tree SLIT tablet. EudraCT identifier: 2007-003234-42.