Observational study on the tolerability of cluster subcutaneous immunotherapy in patients with rhinoconjunctivitis with or without asthma sensitized to pollen: the SIMO study

Abstract

Background: The objective of this study was to determine whether a cluster scheme of allergic immunotherapy (AIT), starting administration of the therapeutic extract with the highest available concentration vial (vial B) of Allergovit®, affords adequate safety and tolerance under conditions of routine clinical practice. Methods: An observational study with retrospective collection of data from protocolled patients' medical records was designed. Patients of 5-65 years old with diagnosis of rhinitis with or without bronchial allergic asthma and hypersensitivity to pollen were selected. Patients were treated with subcutaneous Allergovit®, starting with cluster high doses (500 + 500 TU/1500 + 1500 TU/3000 + 3000 TU) on days 1/8/15 of the build-up phase and 6000 TU monthly on the maintenance phase for 2 years. Results: One hundred and ten patients were included being 51.8% (57) females with a mean age of 30.9 years (95% CI 28.1-33.6). During the first year of AIT, 46 patients suffered 69 adverse reactions (5% of injections). Local reactions were observed in 3.03% of injections (60), and systemic reactions in 0.46% of injections (9). Fifteen systemic reactions were observed in 11 patients during 2 years: 3/Grade 1, 11/Grade 2 and 1/Grade 3, all of them were resolved in 1 day. Conclusions: Cluster AIT reduces the vaccination build-up period, reaching the desired maintenance dose within 2 weeks. The low number of local and systemic reactions observed, the low severity and the resolution of all of them mostly in only 1 day, and the similar safety results observed in other cluster schemes allow to conclude that the cluster scheme evaluated (500 + 500 TU/1500 + 1500 TU/3000 + 3000 TU) was safe for the patients.

Observational study on the tolerability of cluster immunotherapy schedules in patients sensitized to house dust mites

“…Studies from line 2 to 4 were completed with SCIT products containing the same allergen source (HDM), and the Nieto et al study [13] used the same product (Acaroid ® ) with the cluster schedule recommended in the SPC [3]. The Solá et al study was the only one initiating the SCIT with the vial B higher doses as we did, but their study was for other allergens [6]. But the studies could differ in many immunotherapy factors related to the incidence of adverse reactions, or patient characteristics [21][22][23][24][25].…”

“…To date, there is no consensus about which cluster schedule is most effective and safe", and each physician follow their experience in the decision of the best scheme for each patient [5]. Specifically, no information has been published on the build-up immunotherapy using the highest allergen doses contained in the so-called vial B for AIT for HDM, although good safety results were reported for seasonal allergens [6].…”