Biomarkers Relevant to Biologic Therapy in Chronic Rhinosinusitis with Nasal Polyps (CRSwNP): A Scoping Review and Evidence Map

Background/Objectives: Biologic therapies have expanded treatment options for severe chronic rhinosinusitis with nasal polyps (CRSwNP), but biomarkers that can guide treatment selection or monitoring remain uncertain. This scoping review aimed to map biomarker research relevant to biologic therapy in CRSwNP, including aspirin-exacerbated respiratory disease (AERD) to describe its distribution by clinical role, specimen type, and phenotype. Methods: PubMed was searched through 19 June 2026 using a main CRSwNP search strategy and a complementary AERD-focused strategy. English-language primary studies published from 2000 onward were charted by biomarker, reported clinical role, specimen type, and phenotype. Biomarker roles were classified as predictive, monitoring, or both. Results: The final evidence map included 280 primary study reports. Across the overall CRSwNP evidence map, blood eosinophils were the most frequently represented biomarker (n = 182), followed by total IgE (n = 82), tissue eosinophils (n = 54), and FeNO (n = 41). All reports were assigned to a primary phenotype: general CRSwNP (n = 182), CRSwNP with asthma (n = 81), or AERD (n = 17). These represent published reports rather than independent cohorts or validated predictive performance. Conclusions: Biomarker research relevant to biologic therapy in CRSwNP has focused more on baseline prediction and stratification than on longitudinal monitoring. This review maps biomarkers relevant to biologic therapy, with limited direct evidence validating their use for selecting among specific biologics. Future prospective studies using standardized biomarker assessments are needed to evaluate their potential roles in biologic selection and treatment-outcome monitoring.