(Reuters) -Enanta Pharmaceuticals said on Monday its treatment for respiratory syncytial virus failed to shorten the time taken to reduce the severity of some symptoms, missing the primary goal of a mid-stage study.

Shares of the company were down 9% in premarket trading.

While the 186-patient trial failed to meet its main goal of shortening the time to resolution of lower respiratory tract symptoms to mild, it did achieve multiple secondary endpoints, including faster improvement on a patient‑reported severity measure and quicker time to when the virus was not detectable in patients.

Symptoms of RSV based on the patient-reported severity measure include cough, wheezing, phlegm and shortness of breath as well as sore throat and nasal congestion.

RSV is a common respiratory virus that c

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