Amgen & AstraZeneca: Nearly 69% Achieve Remission in Phase 3 — But What Does That Mean for Patients?

Amgen (NASDAQ: AMGN) and AstraZeneca (NASDAQ: AZN) reported positive Phase 3 results for TEZSPIRE (tezepelumab) in eosinophilic esophagitis (EoE), a chronic inflammatory disease that can make swallowing difficult and cause food to become lodged in the esophagus.

In the 368-patient CROSSING trial, nearly 69% of patients receiving the higher dose achieved histologic remission at Week 24, compared with just 3.5% receiving placebo.

More importantly, the trial also demonstrated improvements in swallowing symptoms and visible esophageal inflammation, with benefits sustained through 52 weeks.

The scientific question is particularly interesting: Can targeting an early trigger of inflammation provide broader disease control rather than simply treating its downstream effects?

Understanding the disease

EoE occurs when eosinophils — white blood cells involved in allergic and inflammatory responses — accumulate in the esophagus.

Over time, persistent inflammation can damage the tissue, causing swelling, scarring and narrowing. Patients may experience difficulty swallowing, chest discomfort or food becoming stuck.

Traditional treatments include acid-suppressing medications, dietary changes and swallowed corticosteroids. However, according to Amgen and AstraZeneca, nearly half of patients do not achieve adequate disease control with existing first-line approaches.

How TEZSPIRE works

TEZSPIRE is a monoclonal antibody that blocks thymic stromal lymphopoietin (TSLP), a protein released by cells lining surfaces such as the airways and esophagus.

TSLP acts as an early alarm signal, activating multiple inflammatory pathways.

By blocking that signal, TEZSPIRE attempts to interrupt inflammation closer to its source rather than targeting only one downstream component.

The drug is already approved for severe asthma and chronic rhinosinusitis with nasal polyps. EoE would represent an additional indication, subject to regulatory approval.

For EoE, TEZSPIRE was studied as an injection administered once every four weeks.

CROSSING: The clinical results

The randomized, placebo-controlled Phase 3 trial evaluated two doses of TEZSPIRE in adolescents and adults with uncontrolled EoE.

Week 24 measure	TEZSPIRE 210 mg	TEZSPIRE 420 mg	Placebo
Histologic remission	64.8%	68.9%	3.5%
Swallowing symptom score improvement	−18.8	−22.0	−14.7
Endoscopic inflammation score improvement	−3.6	−3.7	−0.2

Lower symptom and endoscopic scores indicate improvement. Both doses met the co-primary endpoints.

1. Histologic remission: controlling inflammation at the tissue level

Histologic remission means that a tissue biopsy shows eosinophil levels have fallen below a specified threshold.

At Week 24, nearly two-thirds of TEZSPIRE-treated patients achieved this outcome, compared with very few placebo-treated patients.

This suggests substantial suppression of the underlying inflammatory process.

2. Swallowing symptoms: translating biology into daily life

The Dysphagia Symptom Questionnaire (DSQ) measures the frequency and severity of difficulty swallowing.

The higher TEZSPIRE dose improved DSQ scores by 22.0 points, versus 14.7 points for placebo — a 7.3-point additional improvement.

The lower dose produced a smaller placebo-adjusted improvement of 4.1 points, narrowly meeting statistical significance (p=0.049).

This distinction matters. While tissue-level remission rates were similar between doses, the higher dose produced a larger measured improvement in swallowing symptoms.

3. Visible healing: what doctors see during an endoscopy

Researchers also measured swelling, rings, white patches, furrows and narrowing inside the esophagus.

Both TEZSPIRE doses significantly improved these endoscopic findings.

At Week 52, 34.4% of patients receiving 210 mg and 29.5% receiving 420 mg achieved total endoscopic remission, compared with 4.1% on placebo.

These findings suggest that the treatment's effects extend beyond microscopic inflammation to visible features of the disease.

What could make TEZSPIRE important?

Two potential advantages stand out.

First, its mechanism. By blocking TSLP, TEZSPIRE targets an upstream inflammatory signal that contributes to multiple pathways. Its effectiveness in EoE adds evidence that this mechanism may be useful across several inflammatory diseases.

Second, dosing frequency. TEZSPIRE was administered every four weeks, compared with weekly dosing for the established biologic treatment Dupixent (dupilumab) in EoE.

Less frequent dosing could be attractive to some patients managing a lifelong condition.

However, there are important limitations.

Dupixent and TEZSPIRE have not been compared directly in these trials. Differences in patient populations, study designs and endpoints prevent conclusions about which treatment is more effective.

Additionally, strong biopsy results do not guarantee equally large improvements in symptoms. The CROSSING data illustrate why both outcomes must be evaluated.

What remains to be proven?

TEZSPIRE's safety profile was consistent with its existing approved indications. Common adverse events included upper respiratory infections, headache and diarrhea.

The Phase 3 results are encouraging, but TEZSPIRE is not currently approved for EoE.

Regulatory review, longer-term treatment experience and real-world comparisons with existing therapies will help determine its eventual role.

The bigger picture

The most significant finding from CROSSING is not simply the nearly 69% histologic remission rate.

It's the combination of reduced microscopic inflammation, improved swallowing symptoms and visible improvement in esophageal tissue, sustained over one year.

For patients with EoE, that could eventually mean fewer swallowing difficulties, better disease control and another biologic treatment option with less frequent dosing.

For Amgen and AstraZeneca, the findings also reinforce the broader scientific potential of TSLP inhibition across inflammatory diseases.

The next question is whether these clinical benefits translate into regulatory approval and meaningful improvements in patients' everyday lives.

Sources: Amgen and AstraZeneca, Phase 3 CROSSING results, October 20, 2026; United European Gastroenterology Week 2026.