By Peter Loftus 
 

Gilead Sciences Inc. (GILD) has discontinued development of a treatment for a rare lung disease after it failed to meet its efficacy goal in a clinical trial.

The drug, cicletanine, was being evaluated in a midstage, or Phase 2, study of people with pulmonary arterial hypertension, which involves high blood pressure in the arteries of the lungs and causes shortness of breath.

The study's primary efficacy goal was to track whether cicletanine could help patients walk farther in six-minute tests, after 12 weeks of treatment, versus a placebo.

The trial, which began in 2009 and was targeted to enroll 160 patients, was terminated because it didn't meet the primary endpoint, according to an update posted Monday on clinicaltrials.gov, an online database of clinical trials run by the U.S. National Institutes of Health.

Gilead communicated the outcome to study investigators and the PAH medical community earlier this year, spokesman Nathan Kaiser said Tuesday.

"As a result, Gilead will not pursue further development of cicletanine for PAH," Kaiser said.

Gilead had acquired cicletanine in 2008 from Navitas Assets LLC for an initial payment of $10.9 million, plus the potential for future payments if certain development and regulatory milestones were met. The deal gave Gilead rights to cicletanine as a monotherapy for PAH and other indications in the U.S.

Cicletanine was developed by Ipsen (IPN.FR) and is approved in certain European countries for hypertension, according to Gilead.

Gilead shares were up six cents at $56.55 in recent trading.

Write to Peter Loftus at peter.loftus@dowjones.com

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