PETRICHOR is a prospective, non-interventional, single-arm, multi-centre study in Germany evaluating real-world clinical and patient-reported outcomes in adults with severe chronic rhinosinusitis with nasal polyps (CRSwNP), whose disease is inadequately controlled with systemic corticosteroids (SCS) and/or surgery. Eligible participants are newly initiated on subcutaneous tezepelumab in routine clinical practice, in accordance with the European Summary of Product Characteristics (SmPC). Treatment decisions are made jointly by patients and their physicians, independent of study enrollment. No additional diagnostic or monitoring procedures are applied; data are collected using epidemiological methods at baseline and during routine clinical visits for up to 104 weeks.

Inclusion Criteria:

• - Participant must be 18 years of age or older, at the time of signing the informed consent.
• - Confirmed diagnosis of CRSwNP for at least 12 months prior to routine care visit 1.
• - Stable standard of care (SoC) treatment with Intranasal corticosteroids (INCS) for CRSwNP for at least 30 days prior to routine care visit 1.
• - Physician decision that participant is eligible for treatment with Tezepelumab according to locally approved CRSwNP label.
• Participants must be able and willing to read and comprehend written instructions, to collect Patient-reported outcome (PROs) and medication intake via app or alternative mode (paper) and to sign the informed consent document. Use of the mobile app is optional; participants without smartphones will not be excluded. Mode of data capture will be recorded and adjusted for in analyses where relevant.
• - Participants who will be enrolled after index date need to have at least one measurement for SNOT-22 prior (within a maximum of 4 weeks) to index date.
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Exclusion Criteria:

• - Participants who participate in an observational study that might influence the assessment of the current study (participants can be part of the German National Registry for Chronic rhinosinusitis (GENRE-CRS)); or participate in an interventional clinical trial in the last 3 months.
• - Concurrent biologic therapy for CRSwNP or Asthma except where the last dose was administered ≥ 30 days. Stable allergen immunotherapy (defined as a stable dose and regimen at the time of enrolment) is allowed.
• - Endoscopic NP surgery within 6 months prior to index date.
• - Condition (acute or chronic) that, in the investigator's opinion, would limit the participant's ability to complete questionnaires or participate in this study.
• - History of documented anaphylactic reactions/hypersensitivity/serious allergic reactions (immune complex disease) following any biologic therapy.
• - Known hypersensitivity to Tezepelumab or any of its excipients.
• - Pregnancy, planned pregnancy or lactation period.
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The study population will consist of male and female participants aged ≥ 18 years treated by ear-nose-throat specialists with diagnosed severe uncontrolled CRSwNP, for whom a tezepelumab biologic treatment for CRSwNP will be initiated in line with the applicable European Summary of Product Characteristics (SmPC) within routine clinical practice. The decision to initiate or switch to Tezepelumab must be made by the treating physician according to the participant's medical needs and a positive benefit/risk balance. Eligible patients will be included into the study after and independently of the treating physician's treatment and diagnostic decisions. Each participant should meet all the Inclusion Criteria and none of the Exclusion Criteria for this study in order to be part of the study.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure. Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA PhRMA Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org. Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.