AstraZeneca (AZN) and Amgen’s Tezspire Succeeds in Late-Stage Oesophagus Disease Trial

AstraZeneca said Thursday its drug Tezspire met all primary and secondary goals in a late-stage trial. The Phase III CROSSING trial tested Tezspire against placebo in eosinophilic oesophagitis (EoE). AstraZeneca developed the drug jointly with Amgen for this chronic inflammatory oesophagus condition.

What the CROSSING Trial Showed

The Phase III CROSSING trial evaluated two once-every-four-week doses of Tezspire in adult and adolescent EoE patients. Both co-primary endpoints were met: histologic remission and reduced frequency and severity of dysphagia. Improvements appeared by week 24 and held steady through week 52.

• Co-primary endpoints: histologic remission and dysphagia severity, both met at week 24
• Durability: benefits sustained through week 52 across both doses tested
• Patient population: ages 12 to 80 with symptomatic, uncontrolled EoE

AstraZeneca said Tezspire’s safety profile stayed consistent with its already-approved indications, with no new concerns identified.

$AZN $AMGN TEZSPIRE demonstrates positive Phase 3 results in eosinophilic esophagitis across both co-primary and all key secondary endpointshttps://t.co/9zC498V3NG

— Bio Stocks™ (@BioStocks) August 27, 2026

How Tezspire Works Against Inflammation

Tezspire blocks a protein called TSLP, which sits at the top of several inflammatory pathways. TSLP release triggers inflammation linked to asthma, nasal polyps, and now confirmed in EoE. AstraZeneca called this Tezspire’s third epithelial-driven inflammatory disease with positive trial results.

A Contrast With AstraZeneca’s Earlier Setback

AstraZeneca‘s (NYSE: AZN) other biologic, Fasenra, failed part of its own EoE trial in 2022. Fasenra hit the histologic remission goal but missed the dysphagia symptom endpoint entirely. Tezspire’s success on both measures marks a meaningfully different outcome for AstraZeneca’s EoE pipeline.

Commercial Structure Between AstraZeneca and Amgen

Amgen holds US commercial rights to Tezspire, while AstraZeneca sells the drug elsewhere globally. Both companies split costs and profits equally, after AstraZeneca pays Amgen a mid-single-digit royalty. AstraZeneca leads global clinical development work across all of Tezspire’s disease indications.

Tezspire already holds approval in the US, EU, and more than 60 countries. Its current approved use covers add-on maintenance treatment for severe asthma in patients aged 12 and older. EoE would mark a meaningful label expansion if regulators grant approval based on these results.

Why EoE Treatment Options Remain Limited

Nearly half of EoE patients fail to achieve adequate control with current first-line treatments. Those options include dietary restriction, swallowed topical corticosteroids, and proton pump inhibitors. Investigator Arjan Bredenoord of Amsterdam UMC said many patients still face daily swallowing difficulty despite existing therapies.

• Current first-line options: dietary restriction, topical corticosteroids, proton pump inhibitors
• Failure rate: nearly half of patients lack adequate symptom control today
• Disease impact: risk of food impaction and esophageal narrowing over time

Competitive Landscape in EoE

Sanofi and Regeneron’s Dupixent already holds approval for EoE, making it Tezspire’s direct competitor. AstraZeneca and Amgen now have late-stage data supporting a second treatment option for this same patient population. Analysts have previously noted Tezspire’s different TSLP-targeting mechanism could carve out distinct clinical positioning.

Pipeline Outlook

Tezspire’s CROSSING trial success strengthens AstraZeneca’s broader immunology pipeline heading into 2027. Regulatory filings for EoE would follow AstraZeneca’s existing submissions for chronic rhinosinusitis with nasal polyps. Continued data across multiple inflammatory diseases positions Tezspire as a growing franchise for both partners.

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