Extension of Dupilumab Injection Intervals in Chronic Rhinosinusitis with Nasal Polyps: A Real-World Study

Background/Objectives: Dupilumab is an effective long-term treatment for chronic rhinosinusitis with nasal polyps (CRSwNP), but continuous biweekly (Q2W) treatment is associated with high costs, cumulative drug exposure, and treatment burden. Extending injection intervals may reduce these burdens. This real-world study aimed to evaluate the feasibility and clinical outcomes of dupilumab interval extension compared with continued standard Q2W dosing. Methods: In this retrospective single-center study, 35 adults with CRSwNP who had received dupilumab 300 mg Q2W for >12 months underwent a stepwise interval-extension attempt (two-week increments, ≥6 months between steps) and were compared with 30 patients who continued Q2W dosing. Clinical outcomes were assessed every six months using the Sino-Nasal Outcome Test-22 (SNOT-22) and Nasal Polyp Score (NPS). Results: Of the 35 patients, 19 patients (54%) reached a dosing interval of Q4W or longer, and eight patients (23%) maintained a partial extension to Q3W after not tolerating Q4W. The remaining eight patients (23%) returned to Q2W. Thus, 27 patients (77%) stayed on an extended interval beyond the standard Q2W regimen, which was maintained throughout follow-up without reversion to a shorter regimen. SNOT-22 and NPS improved significantly after dupilumab initiation and remained stable throughout follow-up in both groups, with no significant between-group differences in longitudinal outcomes. No patient needed rescue treatments during follow-up. Conclusions: In selected clinically stable patients with CRSwNP, dupilumab interval extension appeared feasible and was associated with maintained disease. Individualized dose tapering, including intermediate intervals such as Q3W, may reduce treatment burden without compromising disease control. Larger prospective studies are needed to define optimal extension protocols and identify predictors of successful interval extension.