Tezepelumab, a First-in-Class Injectable Asthma Drug, Shows Promise in Trial

New AstraZeneca, Amgen drug reduces exacerbations by up to 71%

Tezepelumab (AstraZeneca/Amgen), a new kind of injectable biotech treatment for severe asthma, may help a much broader range of patients than existing medicines, findings from a mid-stage clinical trial show.

The phase 2b trial involving 584 patients showed the experimental drug reduced the annual rate of asthma exacerbations by 61% to 71% depending on dose, Reuters reports. The results could put the first-in-class injection in a strong position in a competitive market as it heads into phase 3 tests later this year or early next year.

“Tezepelumab appears to be the broadest and most promising biologic for the treatment of persistent uncontrolled asthma to date,” Dr. Elisabeth Bel of Amsterdam’s Academic Medical Center wrote in an editorial in the New England Journal of Medicine. Still, she cautioned researchers needed to confirm its safety profile in larger trials, since there was a potential risk its impact on the immune system might lead to infections.

Reuters reported that shares in AstraZeneca rose 1% following the news, with Barclays analysts citing it as an example of the strength of the drug pipeline beyond cancer, which will be in focus at a medical meeting in Madrid this weekend.

Injections for severe asthma have opened up a multibillion-dollar market as competing drug-makers have raced to develop antibody-based medicines for the 15% or more of patients who do poorly even on the latest inhalers. Despite treatment advances in recent decades, Reuters notes, their asthma is still not well controlled by standard therapy, which consists of inhaled steroids and drugs to open the airways.

Mepolizumab (Nucala, GlaxoSmithKline) and reslizumab (Cinqair, Teva) are recently approved injectable drugs, and benralizumab (AstraZeneca) is likely to join them soon, since it is awaiting approval in the fourth quarter of this year, Reuters says. Dupilumab (Dupixent, Sanofi), already approved for severe eczema, is a bit further behind but is widely seen as a strong contender. However, these medicines only appear to help people with certain types of severe asthma, by targeting specific inflammatory chemicals in the body that drive asthma, making them suitable for subgroups of patients.

Tezepelumab is different because it acts further upstream in the inflammatory cascade responsible for asthma by blocking the action of a cell-signaling protein called thymic stromal lymphopoietin. That means it can help a wider range of patients and could be a “game-changer,” according Tom Keith-Roach, head of AstraZeneca’s respiratory, inflammation, and autoimmune business.

Biotech drugs for severe asthma are already worth $2 billion in annual sales, and Keith-Roach believes there is significant scope for growth since only about 10% of patients who might benefit are getting them.

The results of the new asthma study, which were published online by the New England Journal of Medicine, will also be presented at the European Respiratory Society annual meeting in Milan next week.

The randomized, double-blind, placebo-controlled trial involved patients whose asthma remained uncontrolled despite treatment with long-acting beta-agonists and medium-to-high doses of inhaled glucocorticoids. Researchers compared subcutaneous tezepelumab at three dose levels with placebo over a 52-week treatment period. The primary endpoint was the annualized rate of asthma exacerbations (events per patient-year) at week 52. The use of tezepelumab at a dose of 70 mg every four weeks, 210 mg every four weeks, or 280 mg every two weeks resulted in annualized asthma exacerbation rates at week 52 of 0.26, 0.19, and 0.22, respectively, compared with 0.67 in the placebo group.

Sources: Reuters; September 6, 2017; NEJM; September 7, 2017.