Phase 3 Demonstrated Histologic Remission and Improved Dysphagia

AstraZeneca (AZN) and Amgen (AMGN)'s Tezspire (tezepelumab-ekko) achieved all co-primary endpoints in the 24-week Phase 3 CROSSING trial for eosinophilic esophagitis (EoE). Histologic remission was defined as the proportion of patients with ≤6 eosinophils per high-power field in esophageal tissue, and symptom improvement was assessed by the Dysphagia Symptom Questionnaire (DSQ) change. Both doses showed statistically significant and clinically meaningful improvements compared to placebo, with effects sustained through Week 52. However, as this is a top-line result, detailed remission rates, DSQ changes, and safety data will be critical for value assessment through future conference presentations.

Targeting the Upstream of Epithelial-Derived Inflammation by Blocking TSLP

Tezspire is the first-in-class human monoclonal antibody that blocks thymic stromal lymphopoietin (TSLP), an upstream cytokine that triggers allergic and eosinophilic inflammation. CROSSING was a randomized, double-blind Phase 3 trial enrolling 368 patients aged 12–80 with persistent symptoms, assigned 1:1:1 to low-dose, high-dose, or placebo, with subcutaneous injections every four weeks. Patients already using proton pump inhibitors (PPIs) and oral corticosteroids were included to evaluate the drug's value as an add-on therapy in real-world settings. With over 470,000 U.S. patients and about half not adequately controlled with first-line therapy, the simultaneous improvement in histology and patient-reported symptoms could create clinical differentiation.

Second Biologic Enters the Market Dominated by Dupilumab

The current key competitor is Sanofi (SNY) and Regeneron Pharmaceuticals (REGN)'s Dupixent (dupilumab), which blocks the interleukin-4 receptor alpha (IL-4Rα) to inhibit IL-4 and IL-13 signaling. FDA approved Dupixent for EoE in patients aged 12 and above weighing at least 40 kg on May 20, 2022, and expanded it to patients aged 1 and above weighing at least 15 kg on January 25, 2024. The global EoE treatment market is estimated at USD 477.7 million in 2025 and is projected to reach USD 7.5 billion by 2035, meaning Tezspire could disrupt the market structure dominated by a single biologic. While dietary therapy, PPIs, and local steroids remain standard first-line treatments, Tezspire's competitive edge will be determined not by direct comparison with Dupixent but by its distinct upstream target and performance in patients with inadequate response.

Third Indication Could Be the Next Growth Lever for Blockbuster Potential

Tezspire is an FDA-approved product for severe asthma since December 17, 2021, and its indication was expanded in October 2025 to include uncontrolled chronic rhinosinusitis with nasal polyps (CRSwNP). EoE is still in the Phase 3 success stage, and both companies plan to share results with regulatory authorities, with detailed data disclosure and regulatory submission as the next key milestones. Combined sales of Tezspire reached USD 1.15 billion in the first half of 2026, with AstraZeneca's second-quarter revenue at USD 390 million, a 45% increase year-over-year. The companies co-commercialize in the U.S. and share development costs and profits equally, while AstraZeneca recognizes sales outside the U.S. and pays Amgen a mid-single-digit inventor royalty, distributing the economic benefits of EoE expansion between the two.