Retrospective, Real Life Study on the Effectiveness and Safety of a Depigmented-Polymerized Subcutaneous Vaccine Containing a Mixture of Grasses and Olea europaea.

Introduction: Allergen immunotherapy is the only modifying treatment of the natural course of respiratory allergic diseases; however, the lack of evidence leads to little inconclusive results. Real life studies are on the rise and are becoming a valuable tool to confirm and complement findings from clinical trials. The objective of this study was to evaluate the effectiveness and safety of a depigmented-polymerized undiluted subcutaneous extract of grass and olive pollen, under routine clinical practice conditions.

Methods: This was an observational, retrospective, longitudinal, single-center study on the use of a 2-pollen (grass mix and Olea europaea) undiluted subcutaneous extract over at least 3 consecutive years. Data were collected from 76 patients (n = 44 female; median age: 12.5 years old) diagnosed with allergic rhinoconjunctivitis with/without allergic asthma due to sensitization to both grasses and O. europaea. Primary and secondary effectiveness endpoints were symptom severity, concomitant medication, and immunological profile before and after completing the immunotherapy. A 2-year follow-up of patients' symptoms and medication history after completing the subcutaneous immunotherapy (SCIT) was performed.

Results: There was a significant improvement of symptoms and medication consumption after 3 years of SCIT treatment, and a significant decrease in specific IgE levels for grasses and O. europaea was observed after finishing the treatment.

Conclusion: Three years treatment of allergic patients using an undiluted mixture of two allergen extracts was shown to be safe and effective for rhinitis and asthma, with efficacy maintained for at least 2 years after finishing SCIT. These results reinforce the importance of real life clinical data in addition to those from clinical trials, helping to individualize allergic treatments.