Clinical Trial With a Depigmented, Polymerized Mite Mixture Extract at Maximum Concentrations

Abstract

BackgroundEfficacy of allergen immunotherapy is dose‐dependent; however, high doses of allergen may imply a greater risk of adverse reactions.ObjectiveTo assess the safety and tolerability of subcutaneous immunotherapy (SCIT) with mixtures of mite allergen extracts, Dermatophagoides pteronyssinus/Blomia tropicalis (Dpt/Bt) and Dermatophagoides pteronyssinus/Lepidoglyphus destructor (Dpt/Ld) at maximum concentrations, in adult patients with allergic rhinitis or rhinoconjunctivitis, and controlled allergic asthma due to a clinically relevant sensitisation to these mites.MethodsAn open‐label, noncontrolled, nonrandomised, phase IIb clinical trial was carried out in three hospitals in Spain between September 2014 and May 2018. Patients received SCIT of either Dpt/Bt (100/1000 DPP/mL) or Dpt/Ld (100/100 DPP/mL) in two phases: a rush build‐up phase on the first day (0.2 mL and 0.3 mL with a 30‐min interval) and a monthly maintenance phase administration (0.5 mL) up to 48 months.ResultsForty patients were recruited for the study, seven allocated to the Dpt/Bt group and 33 to the Dpt/Ld. None experienced immediate or delayed systemic Grade ≥ 2 reactions (EAACI classification) (systemic reactions were mostly Grade 1) nor died during the study. Local reactions were mostly mild (0‒10 cm). Thirty‐nine patients (97.5%) experienced at least one adverse event (AE). Of the 283 reported AEs, eight (2.8%) were systemic reactions experienced by six (15%) subjects and 14 (4.9%) were local reactions sustained by ten (25%) subjects.ConclusionsSCIT treatment of patients with allergic rhinitis or rhinoconjunctivitis and controlled asthma with mixtures of Dpt/Bt and Dpt/Ld allergen extracts at maximum concentrations showed a favourable safety profile.