Safety of cluster specific immunotherapy with a modified high-dose house dust mite extract

Although the efficacy and safety of high dose hypoallergenic mite subcutaneous immunotherapy (SCIT) using a conventional administration schedule has already been demonstrated, there is no reported experience on the safety of these extracts with cluster schedules. We wanted to determine whether the use of a cluster schedule of a hypoallergenic allergen with a high concentration of house dust mite allergens commonly used in normal practice was safe and well-tolerated in patients with dust mite allergy.

Multicentre, observational, retrospective study of dust mite allergic patients treated with a cluster schedule of SCIT (Acaroid; Day 1: 300/300 therapeutic units, TU--Day 8: 1000/1000 TU--Day 15: 3000/3000 TU) in 23 Spanish sites.

Cluster schedule was used on 434 patients (40.1% children), with a total of 3256 doses (38.2% in children). There were 88 clinically relevant adverse reactions, 79 out of them local and 9 systemic (but mild-moderate) that amounted to 2.7% of all the administered doses. All the patients fulfilled the cluster schedule.

Cluster schedule with high dose hypoallergenic mite-SCIT was safe and well-tolerated in routine clinical practice. Therefore, its use could reduce the costs and time needed to achieve the desired maintenance dose and increase compliance.