A Phase II trial has demonstrated that Fasenra (benralizumab) can achieve near-complete depletion of eosinophils and improve clinical outcomes in hypereosinophilic syndrome (HES).
In the randomized phase of the 20-patient trial, the primary efficacy endpoint was the percentage of patients who reduced their absolute blood eosinophil counts by 50% or more at week 12. This was achieved by 90% of patients treated with Fasenra compared with 30% of patients treated with placebo, a statistically significant difference.
In the open-label phase of the trial, 74% of patients maintained a reduction in eosinophil counts and had clinical improvements in their symptoms through week 48. Of these patients, 64% were able to taper background HES medications. In patients from whom tissue biopsies were obtained (gastrointestinal tract and skin) there was near-complete depletion of eosinophils following treatment with Fasenra.
“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,” said Mene Pangalos, Executive Vice President and President BioPharmaceuticals R&D, AstraZeneca.
A collaboration trial between AstraZeneca and NIAID
HES is a group of rare, potentially fatal disorders characterized by high numbers of eosinophils in blood and tissues which can cause progressive, potentially life-threatening organ damage. At the start of the Phase II trial, patients had significantly elevated levels of blood eosinophils ranging from 1,000 to 21,580 cells per μl.
During the 48-week treatment period, the three most frequently reported adverse events attributed to Fasenra included headache, elevated lactate dehydrogenase (LDH) concentration and chills. The observed increases in LDH occurred after the first dose of Fasenra and resolved within 48 hours. The trial was a collaboration between AstraZeneca and the US National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health.
Orphan Drug Designation
Fasenra is currently approved as an add-on maintenance treatment for severe, eosinophilic asthma in the US, EU, Japan and other countries. The US Food and Drug Administration (FDA) granted Orphan Drug Designation for Fasenra for the treatment of HES in February 2019.
The results are published in the New England Journal of Medicine.
Photo of Mene Pangalos: AstraZeneca