Long-Term Efficacy of Dupilumab for Eosinophilic Chronic Rhinosinusitis

Background Eosinophilic chronic rhinosinusitis (eCRS) is a type 2 inflammatory disease that frequently recurs after surgery. In recent years, dupilumab has been available for the treatment of refractory chronic rhinosinusitis since 2020 in Japan. Although there are some reports of its usefulness, there are not enough reports of its clinical efficacy for longer than 1 year, especially for olfactory recovery. Methods Twenty patients with eCRS who had recurrence after surgery and had been receiving dupilumab were enrolled retrospectively. The nasal polyp score (NPS), computed tomography (CT) score, T&T olfactometer, and olfactory cleft opacification on CT were evaluated at baseline, at an average of 5.1 months later (short term), and at an average of 18.3 months later (long term). Results At the short-term evaluation, there were significant improvements in the NPS and CT scores ( P < .001, P = .008, respectively). The CT score was further improved at the long-term evaluation compared to the short-term evaluation ( P = .018) and baseline ( P = .008). T&T detection/recognition thresholds and olfactory cleft opacification showed significant improvements only at the long-term evaluation compared to baseline ( P = .002, P = .006, and, P = .006, respectively). Conclusion The NPS remained improved, and the CT score showed further improvement with long-term treatment, whereas olfactory function and olfactory cleft opacification showed significant improvement only after long-term treatment. There was a dissociation between the time to improve in the NPS and CT scores and the time to improve in olfactory function and olfactory cleft opacification. Based on these results, dupilumab should be administered for longer than 1 year, especially for olfactory function.