AstraZeneca has announced results of its Fasenra (benralizumab) Phase II trial, showing that the asthma drug can also achieve near-complete depletion of eosinophils and improve clinical outcomes in hypereosinophilic syndrome (HES).

The mid-stage results, which were published in The New England Journal of Medicine (NEJM), stated that 90% of dosed patients were found to have reduced their absolute blood eosinophil counts by 50% or more at week 12, reaching the primary endpoint of the trial. Only 30% of the placebo patients achieved the endpoint, showing Fasenra to make a significant difference.

On top of this, 74% of patients maintained a reduction in eosinophil counts and had clinical improvements in their symptoms through week 48, and of these patients, 64% were able to taper background HES medications.

Gastrointestinal tract and skin tissue biopsies were obtained from a percentage of patients, and found that there was near-complete depletion of eosinophils following treatment with Fasenra.

Mene Pangalos, executive vice president and president BioPharmaceuticals R&D, said: “We are encouraged by these trial results for Fasenra in hypereosinophilic syndrome and the data are potentially important given the limited treatment options for this debilitating disease.”

The study, which was conducted in conjunction with the US National Institutes of Health's National Institute of Allergy and Infectious Diseases, involved 20 patients with platelet-derived growth factor receptor A-negative HES and an eosinophil count of at least 1000 cells per microlitre on stable HES therapy.

HES is a group of diseases that are characterised by an excessive amount of eosinophils, which is a normal cellular component from the myeloid series of the blood that stains red with an eosin stain. These eosinophils can infiltrate the organs of the body, in particular the heart and lungs.

Fasenra is AstraZeneca’s first respiratory biologic, now approved as an add-on maintenance treatment in severe, eosinophilic asthma in the US, EU, Japan and other countries, and in January was recommended by The National Institute for Health and Care Excellence (NICE) after being re-evaluated as cost-effective.