State-of-the-art overview on biological treatment for CRSwNP

Background The majority of patients with uncontrolled severe CRSwNP, asthma and atopic dermatitis share a similar T helper 2 type inflammation linked to their underlying phenotype. This discovery has triggered new research around treatments targeting specific cytokines driving inflammation in CRSwNP like IL-4, IL-13, IL-5 and IgE. Biologicals are increasingly tested as additional tre- atment for patients suffering from severe chronic rhinosinusitis with nasal polyps (CRSwNP). Their efficacy has been demonstrated in multiple studies. All studies differ in terms of baseline characteristics of included patients and outcome parameters analysed. Aims A comparative analysis of the efficacy of reported biologicals for CRSwNP based on the published data for phase 2 and 3 studies. The aim was to provide a comprehensive overview across the different biologicals and outcome parameters. Methods In a first step we critically selected out of all available phase 2 and 3 clinical trials the ones containing the most rigorous and compatible study designs. Meaning studies that comply with a need for a clear definition of CRSwNP, at least two administra- tion doses, comparable timeframes and the same outcome parameters studied. This assessment was performed using a PRISMA search. We retained 7 studies with significant data for dupilumab, mepolizumab and omalizumab. In a second step the effect-sizes of treatment with those biologicals were compared for the most important outcome parameters both patient relevant (nasal con- gestion, smell loss and SNOT-22 scores) and patient irrelevant (CT scan Lund-Mackay, smell test and nasal polyp scores). Therapy duration of 16 to 25 weeks was chosen for evaluation of efficacy. Results A direct comparison of efficacy between dupilumab, mepolizumab and omalizumab is challenging given differences in inclusion criteria, outcome parameters and time-points of analyses. We have been able to conclude that effect sizes of dupilumab, mepolizumab and omalizumab seem large enough to reflect a major reduction in symptom burden as experienced by patients suffering from refractory CRSwNP. The effect size of dupilumab on both patient relevant and patient irrelevant parameters of smell loss are clearly significant and reflect the clinical experience of major reduction of smell impairment in treated patients. Conclusion Despite the heterogeneity of protocols, dosages and time-points of analyses of biological trials in CRSwNP, this over- view highlights outcomes of biological treatment in CRSwNP in a comprehensive way. Real-life registries, comparative trials and/ or endotype-driven treatment plans are needed to provide the answers to the multiple questions that are still open today.