stella
AsthmaNovember 2021Summary reviewed July 2026

An Asthma Injection Cut Airway Inflammation by 85% in 28 Weeks

Researchers tested tezepelumab, an antibody that blocks a protein called TSLP, in people with moderate-to-severe asthma. After 28 weeks, the drug reduced inflammation-causing eosinophils in the airways by 85% compared to placebo and improved airway responsiveness.

What the trial was testing

The CASCADE enrolled 116 patients with asthma. The study was sponsored by AstraZeneca and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was initial testing (phase 2). Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

Tezepelumab reduced airway eosinophils by 85% in people with uncontrolled asthma.

The Lancet. Respiratory medicine · 2021 · NCT03688074

These findings — that fewer eosinophils in airways after 28 weeks of treatment — were published in the The Lancet. Respiratory medicine and represent the headline result of the study.

Researchers tracked outcomes across 116 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with asthma, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Tezepelumab is FDA-approved for severe asthma (brand name Tezspire). This study helps explain how it works—by reducing inflammation in the airways. If you have moderate-to-severe asthma that's hard to control, ask your doctor if this treatment might be right for you.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.