AstraZeneca's Fasenra woes continue as it comes up short in eosinophilic esophagitis

Reaching blockbuster status last year for its asthma drug Fasenra, AstraZeneca had high hopes of expanding its label and running down GSK’s rival treatment, Nucala.

But Fasenra’s upward trajectory has stalled in 2022. In March came an FDA rejection to treat rhinosinusitis. And, Tuesday, AZ reported shaky data in a phase 3 trial in eosinophilic esophagitis (EoE).

While Fasenra met one objective, showing histological disease remission compared to placebo, it came up short on the other as it failed to relieve the swallowing issues (dysphagia) that accompany the disorder.

An approval to treat the allergic, inflammatory condition would have given Fasenra a much-needed edge on Nucala, which has not been blessed for EoE.  

“(The results) confirm that Fasenra achieved near complete depletion of tissue eosinophils, consistent with its mechanism of action; however, this did not translate into an improvement in dysphagia symptoms,” Mene Pangalos, AZ’s R&D chief, said in a release, adding that the company will continue to analyze the data set.

Fasenra was approved in 2017 as an add-on maintenance treatment for severe eosinophilic asthma and two years later got a nod for its self-administration injector pen.

Meanwhile, GSK has proven more adept at expanding Nucala’s label after its initial approval in 2015 to treat severe asthma. Nods for eosinophilic diseases including granulomatosis with polyangiitis (2017) and hypereosinophilic syndrome (2020) were followed by a green light for rhinosinusitis with nasal polyps last year.  

In 2021, AZ reported $1.26 billion in Fasenra sales, up 31% from 2020, while Nucala pulled in $1.49 billion.

Another player that has emerged in the space is Sanofi and Regeneron’s powerhouse Dupixent. In May, it became the first drug approved for EoE. That came on top of FDA endorsements for Dupixent in asthma (2018) and rhinosinusitis with nasal polyps (2019).

AZ has phase 3 trials in the works for hypereosinophilic syndrome, which is expected to read out later this year, and granulomatosis with polyangiitis, which is expected to wrap up next year.