Validating Efficacy in Real-World Settings in Russia

AstraZeneca (AZN) has initiated the ARES observational study (NCT07399665) across approximately 10 sites in Russia. Tezspire (tezepelumab-ekko) is a monoclonal antibody that blocks thymic stromal lymphopoietin (TSLP). The study will enroll 110 adult patients with chronic rhinosinusitis with nasal polyps (CRSwNP) who have initiated treatment within four weeks. This is a single-arm, non-comparative, retrospective and prospective cohort study, scheduled to begin on December 25, 2025, and conclude in March 2028. This study is designed to generate evidence needed for market penetration by confirming real-world prescription patterns and clinical/patient-reported outcomes, rather than replicating the efficacy of a randomized controlled trial.

Commercialization Phase for a Second Approved Indication

Tezspire is co-developed by AstraZeneca and Amgen (AMGN), with Amgen leading sales in the United States and AstraZeneca leading sales in regions outside the United States. The FDA initially approved Tezspire for severe asthma on December 17, 2021, and subsequently expanded the indication on October 17, 2025, for additional maintenance therapy for patients aged 12 years and older with uncontrolled CRSwNP. In Europe, Tezspire was approved for asthma in September 2022, and the CHMP adopted a positive opinion for the severe CRSwNP indication on September 18, 2025, which was then reflected in the European product information. Therefore, ARES is not a late-stage clinical trial but a post-marketing real-world evidence strategy to measure regional prescription sustainability and patient benefits for an approved and marketed product.

Differentiation of TSLP Inhibitors and Intense Biologics Competition

The standard treatment for CRSwNP is intranasal corticosteroids, short-term systemic steroids, and endoscopic sinus surgery, with biologics added in patients with difficult-to-control disease. Direct competitors include Dupixent (dupilumab), an IL-4Rα inhibitor; Xolair (omalizumab), an IgE inhibitor; and Nucala (mepolizumab), an IL-5 inhibitor, all of which are in the approved and marketed stages. Tezspire blocks TSLP, an upstream target in the inflammatory cascade, and enrolls patients regardless of asthma comorbidity, allowing for the collection of response data from a broad patient population. However, the lack of a comparator arm means that it cannot demonstrate superiority compared to competing drugs, so the commercial value of the results depends on how consistently symptom improvement and reductions in surgery and systemic steroid use are observed in real-world settings.

Building a Foundation for Revenue Expansion in a $6 Billion Market

The global CRSwNP drug market is projected to grow from USD 6.0 billion in 2024 to USD 10.0 billion in 2030, with the expansion of biologics being a major driver. Tezspire's global revenue in 2025 is USD 1.5 billion, a 52% increase year-over-year, already establishing a blockbuster foundation. The real-world evidence collected in ARES can be used to inform prescribing decisions, reimbursement negotiations, and improve patient retention among Russian physicians, but the scope of the study, involving 110 patients in a single country, is limited. In the medium to long term, it will become a data asset that strengthens commercial synergy between indications by providing a single TSLP-targeted therapy for patients with both asthma and CRSwNP.