AstraZeneca said US regulators had granted orphan drug status for its treatment for hypereosinophilic syndrome, a rare condition that can damage organs in the body.
The Food and Drug Administration grants orphan status to medicines intended for the treatment of rare diseases or disorders that affect fewer than 200,000 people in the US.
A phase II clinical trial of the treatment, Fasenra, had been conducted by the US National Institutes of Health in collaboration with AstraZeneca.
The results were expected to be published later in 2019.
At 8:19am: (LON:AZN) AstraZeneca PLC share price was -46p at 5663p