Amgen, AstraZeneca speed toward filing next-gen antibody for asthma after uncorking full late-stage data

On the hunt for a novel competitor to Sanofi and Regeneron’s Dupixent in severe asthma, Amgen and AstraZeneca posted “exciting” results from their next-gen antibody late last year. Now, the partners are showing their hands, and the results look good enough for approval.

Amgen and AstraZeneca’s tezepelumab plus standard of care cut the rate of severe asthma attacks by 56% at the one-year mark compared with SOC alone, according to full data from the Phase III NAVIGATOR study presented Friday at the virtual American Academy of Allergy, Asthma & Immunology meeting. And those significant results were consistent regardless of patients’ baseline eosinophil counts.

The full results tee up tezepelumab, a once-monthly infusion that already sports the FDA’s breakthrough therapy designation, for a quick filing from the Big Pharma partners. The pair released topline results from the NAVIGATOR study back in November, calling the data “exciting” and “groundbreaking.”

In a release, Amgen said the NAVIGATOR results make tezepelumab the first biologic to significantly lower the rate of annualized asthma exacerbations over standard of care regardless of baseline eosinophils, specialized white blood cells that cause inflammation. The lower eosinophil counts are of particular interest for analysts, who have noted that other severe asthma meds, including Dupixent, aren’t approved for those patients.

The drug also spurred significant reductions regardless of patients’ allergy status and fractional exhaled nitric oxide (FeNO) level, both common biomarkers in determining treatment options.

Tezepelumab is designed to block TSLP, an epithelial cytokine that sits upstream of inflammatory cytokines such as IL-4, IL-5 and IL-13. By targeting multiple pathways responsible for asthma, researchers believe that they could help those whose symptoms are not alleviated by current therapies.

However, tezepelumab has flopped on at least one key differentiator from drugs like Dupixent. In Phase III data presented in December, tezepelumab failed to lower the number of background oral corticosteroids patients were required to take to manage their symptoms. Amgen called the results “surprising” and tried to tag trial design flaws as a possible culprit. Full data from that study have yet to be released.

Either way, there’s a problem: Dupixent did cut the number of background corticosteroids in its own pivotal trials in severe asthma, and analysts worry physicians primarily care about getting their patients off as many steroids as possible.

Even still — and this is a significant underscore to the market potential here — some analysts have placed tezepelumab’s potential peak sales at $2.5 billion. But that’s the cost of hoping to do business in the same market as Dupixent, the leader in the atopic dermatitis clubhouse and the linchpin of Sanofi and Regeneron’s near-term growth plans.