Real-world safety and clinical outcomes of cluster subcutaneous immunotherapy with olive pollen extracts, with or without grass pollen, in patients with allergic rhinoconjunctivitis and/or asthma

Abstract

Abstract Background Allergen immunotherapy (AIT) is the only treatment capable of modifying the natural course of IgE-mediated allergic diseases induced by aeroallergens. Cluster schedules for subcutaneous AIT (SCIT) with hypoallergenic depot extracts enable faster dose escalation while maintaining a favorable safety profile. However, specific data on the use of Olea europaea extracts, alone or combined with grass pollen, remain limited, particularly in Mediterranean populations. Methods The OLGA study was a multicenter, retrospective, real-world analysis conducted in 16 allergy centers across Spain. Patients with IgE-mediated allergic rhinoconjunctivitis and/or asthma sensitized to Olea europaea , with or without grass pollen, received SCIT administered according to a cluster schedule. Safety and clinical outcomes were assessed over one year through physician-reported adverse reactions (ARs) and changes in nasal, non-nasal, and asthmatic symptom scores. Results Data from 245 patients were analyzed (51% male; mean age 26.6 years). ARs occurred in 27.3% of patients and were predominantly mild local reactions; no grade 3 or higher systemic reactions, hospitalizations, or treatment discontinuations due to ARs were reported. Favorable changes were observed across all symptom domains during follow-up (nasal Δ− 5.05; non-nasal Δ− 4.00; total Δ− 9.06; all p < 0.001), together with a reduction in the annual number of asthma exacerbations (Δ− 2.7; p < 0.001). The proportion of patients meeting predefined thresholds for clinically relevant change exceeded 93% across all evaluated domains. Similar outcome patterns were observed for olive-only and olive-plus-grass products. Conclusions This multicenter real-world study provides information on the safety profile and clinical outcomes observed in patients receiving depot allergoid SCIT administered in a cluster schedule. The findings contribute to the evidence describing the use of accelerated SCIT schedules in patients sensitized to Olea europaea pollen under routine clinical practice conditions.

The authors' abstract, as published at the source. Allergy Asthma and Clinical Immunology, 2026 · DOI ↗