Shares of KaloBios Pharmaceuticals Inc fell nearly 50 percent in extended trade after the company said it would stop developing an asthma drug that failed in a mid-stage study.
The drug, KB003, failed to bring about a clinically meaningful improvement in the pulmonary function of patients with severe asthma when tested against a placebo in 160 patients.
The San Francisco-based company said it would focus on developing other treatments in its pipeline, which include a drug for cancer and another to prevent a common gram negative bacterium.
KaloBios shares fell to a low of $2.65 in extended trading.
The company had a market capitalization of about $150 million based on its Wednesday close of $4.65 on the Nasdaq.
(Reporting by Zeba Siddiqui in Bangalore; Editing by Sriraj Kalluvila)