Clinical Remission in Patients Affected by Severe Eosinophilic Asthma on Dupilumab Therapy: A Long-Term Real-Life Study

: Background. Nowadays, highly selective biological drugs offer the possibility of treating severe type 2 asthma. However, in the real-life setting, it is crucial to confirm the validity of the chosen biological treatment by evaluating the achievement of clinical remission. Study purpose. The main aims of this real-life study were to evaluate the efficacy of dupilumab in terms of clinical, functional, and inflammatory outcomes at 6, 12, 18, and 24 months of treatment and to estimate the percentage of patients achieving partial or complete clinical remission at 12 and 24 months of treatment. In addition, we attempted to identify whether baseline clinical characteristics of patients could be associated with clinical remission at 24 months of treatment. Materials and methods. In this observational prospective study, 20 outpatients with severe uncontrolled eosinophilic asthma were prescribed dupilumab and followed-up after 6, 12, 18, and 24 months of treatment. At each patient visit, the need for oral corticosteroids (OCS) and corticosteroid required dose, number of exacerbations during the previous year or from the previous visit, asthma control test (ACT) score, pre-bronchodilator forced expiratory volume in the 1st second (FEV1), fractional exhaled nitric oxide at a flow rate of 50 mL/s (FeNO50), and blood eosinophil count were assessed. Results. The number of OCS-dependent patients was reduced from 10 (50%) at baseline to 5 (25%) at one year (T12) and 2 years (T24). The average dose of OCS required by patients demonstrated a significant reduction at T12 (12.5 ± 13.75 mg vs. 2.63 ± 3.94 mg, p = 0.015), remaining significant even at T24 (12.5 ± 13.75 mg vs. 2.63 ± 3.94 mg, p = 0.016). The number of exacerbators showed a statistically significant decrease at T24 (10 patients, 50% vs. 3 patients, 15%, p = 0.03). The mean number of exacerbations demonstrated a statistically significant reduction at T24 (1.45 ± 1.58 vs. 0.25 ± 0.43, p = 0.02). The ACT score improved in a statistically significant manner at T12 (15.30 ± 4.16 vs. 21.40 ± 2.35, p < 0.0001), improving further at T24 (15.30 ± 4.16 vs. 22.10 ± 2.59, p < 0.0001). The improvement in pre-bronchodilator FEV1 values reached statistical significance at T24 (79.5 ± 14.4 vs. 87.7 ± 13.8, p = 0.03). The reduction in flow at the level of the small airways (FEF25-75%) also demonstrated an improvement, although it did not reach statistical significance either at T12 or T24. A total of 11 patients (55%) showed clinical remission at T12 (6 complete + 5 partial) and 12 patients (60%) reached clinical remission at T24 (9 complete + 3 partial). Only obesity was associated with a negative odds ratio (OR) for achieving clinical remission at T24 (OR: 0.03, 95% CI: 0.002-0.41, p = 0.004). No other statistically significant differences in baseline characteristics emerged between patients who reached clinical remission at T24 and the group of patients who did not achieve this outcome. Conclusion. Dupilumab appears to be an effective drug in promoting achievement of clinical remission in patients with severe uncontrolled eosinophilic asthma. The achievement of clinical remission should be continuously evaluated during treatment. Further studies are needed to clarify whether certain baseline clinical characteristics can help predict dupilumab favorable outcomes.