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Anthera Pharmaceuticals Inc said on Tuesday that its drug to treat certain cystic fibrosis patients failed a late-stage study, sending the company's shares tumbling nearly 70 percent in after-hours trading.

The latest setback for Anthera comes just over a month after the company said an experimental drug to treat lupus had also failed in a late-stage study.

Cystic fibrosis is an inherited genetic condition that mainly affects the digestive and reproductive systems and the lungs. The drug, sollpura, was being tested on patients whose cystic fibrosis had led to exocrine pancreatic insufficiency (EPI), an enzyme deficiency that leads to improper digestion.

Sollpura was being tested on its ability to help patients absorb fat in a non-inferiority trial, where a new treatment has to show it is not clinically worse than an active treatment with regards to specified targets.

Sollpura failed on this count when its performance was compared with Janssen Pharmaceuticals' pancreaze, Anthera said.

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However, Anthera said sollpura's ability to absorb protein was not clinically worse and that, based on this finding, it would start a new study in the first quarter of 2017.

Anthera's shares were down about 67 percent at 69 cents in trading after the bell on Tuesday. Up to the day's close, they had lost 57 percent this year. (Reporting by Dipika Jain in Bengaluru; Editing by Savio D'Souza)