Strike two: Gilead chalks up another setback for top pipeline prospect simtuzumab

Gilead has racked up its second straight setback on simtuzumab, scrapping a mid-stage study for idiopathic pulmonary fibrosis after a data monitoring group concluded that the drug wasn't working as expected.

The drug, which blocks the LOXL2 enzyme, has already flunked out for pancreatic cancer, flopping in another mid-stage study back in the fall of 2014. Gilead ($GILD) has had high hopes that the drug could work for both tumor progression as well as in reversing fibrosis.

"Gilead has also reviewed the data and determined the study has not shown evidence of a treatment benefit in the group of patients randomized to receive simtuzumab," said the company in a brief statement. Gilead is well known for its tight-lipped approach to drug development and marketing. 

Gilead shares are down 1.7% in premarket trading Wednesday.

Simtuzumab has been tapped as one of the leading drugs in the clinic for non-alcoholic steatohepatitis, or NASH. While rivals have been looking to blunt the fatty liver disease in less advanced cases, simtuzumab is being studied for its potential to reverse cirrhosis. Setting the bar higher in the clinic has attracted increased scrutiny among analysts intrigued by the megablockbuster prospects that await any newly approved drug. But back-to-back failures won't improve Gilead's odds in NASH.

Simtuzumab is also in a clinical trial for primary sclerosing cholangitis (PSC), and Gilead notes that the data monitoring group has recommended that both the NASH and PSC studies should go on to their scheduled conclusions.

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