Background Chronic rhinosinusitis with nasal polyps (CRSwNP) is a multifactorial inflammatory disease of the nasal and para-nasal mucosa, most often caused by TH2 inflammation. IgE antibodies play an important role in this disease. The anti-IgE antibody omalizumab was approved in August 2020 for the treatment of patients aged 18 years and older with severe CRSwNP as add-on therapy to intranasal corticosteroids (INCS) when adequate disease control cannot be achieved with INCS alone. Omlyclo, a biosimilar of Xolair containing the active ingredient omalizumab (CT-P39), was approved in the EU in May 2024. In Germany, Omlyclo has been officially available by prescription since September 15, 2025, and is available as 75 mg and 150 mg pre-filled syringes and pre-filled pens. An extension of the marketing authorization for the 300 mg dosage followed in November 2025. Methods A literature search was conducted to analyze the immunologyof CRSwNP and to identify the evidence for the efficacy of omalizumabin this disease through searches in Medline, PubMed, national and international study and guideline registries, and the Cochrane Library. Results Based on this information from the international literature, an expert panel from the Association of German Allergists and the German Society for Otorhinolaryngology and Head and Neck Surgery provides recommendations for the use of the omalizumab biosimilar CTP39 in CRSwNP within the German healthcare system. Conclusion The omalizumab biosimilar is approved for patients aged 18 years and older with severe chronic rhinosinusitis with nasal polyps as add-on therapy to intranasal corticosteroids when adequate disease control cannot be achieved with singel intranasal corticosteroids therapy. A documentation form has been developed to simplify the documentation of the indication.