Efficacy and predictors of rapid response to omalizumab therapy in patients with seasonal allergic rhinitis: a cohort study.

BACKGROUND: The availability of anti-IgE therapy for allergic rhinitis (AR) has actualized the need to develop variants of this treatment according to predictors of rapid response and the tactics of treatment initiation. 
AIMS: To study efficacy and predictors of response to omalizumab in patients with seasonal AR (SAR). 
MATERIALS AND METHODS: Patients with moderate or severe SAR with insufficient effectiveness of traditional treatment for at least 3 months in previous pollen season or with no effect of therapy in current season were included. The decision to prescribe omalizumab was made based on the visual analog scale (VAS) in the previous or current season. Dosage and frequency of administration (every 2 or 4 weeks) were determined according to the table values due to the instructions. The patients were observed for 2 months. At follow-up visits (1 and 2 months later), AR symptom control was assessed using VAS and TNSS. Therapy was considered effective when the VAS remained 30 or decreased 30 after 4 and 8 weeks from the start of therapy, depending on the initiation period. 
RESULTS: The study enrolled 30 patients with AR history of 14 years, sensitization to 2 or more groups of allergens in 19 (63,3%) cases, bronchial asthma (BA) in 18 (60%). In 6 patients (20%) omalizumab was initiated before the pollen season, in 24 patients (80%) during the season. After 4 weeks, control of AR manifestations was achieved in 23 (77%) patients, and by week 8, 100% of patients with AR had fully responded to therapy. In patients, the severity of AR symptoms on the VAS/ TNSS scales decreased by 2.7 and 4.7 times, respectively, by 4 weeks of follow-up. The proportion of patients with a slow response by week 4 of therapy was 23%. BMI (lower in the "slow" response group) and history of BA (2.6 times longer in the "slow" responders) were associated with the achievement of this outcome. No adverse events were recorded. 
CONCLUSIONS: Omalizumab in patients with SAR allows to achieve control of manifestations of the disease already after 4 weeks of therapy with its maintenance in follow-up. Predictors of rapid response have been revealed, but their clinical significance requires further study.