The U.S. Food and Drug Administration rejected Actelion Pharmaceuticals Ltd.'s application to seek an expanded use for its blood pressure drug Opsumit.

The Johnson & Johnson unit sought an expansion in the usage of Opsumit to treat adults with inoperable chronic thromboembolic pulmonary hypertension — high pressure in the blood vessels of the lungs caused by the formation of blood clots and related scarring — to improve blood flow to the lungs and exercise capacity.

Opsumit is already approved in the U.S. for treating pulmonary arterial hypertension, a type of high blood pressure that affects the arteries in the lungs and the right side of the heart, to reduce the risks of disease progression and hospitalization.

In its complete response letter, the drug regulator stated that additional data is required to evaluate the use of the drug in the treatment of chronic thromboembolic pulmonary hypertension, according to a Jan. 16 news release.

Actelion, which was acquired by Johnson & Johnson for $30 billion in 2017, was seeking the expanded approval for Opsumit based on data from a phase 2 study, named Merit-1, which showed that the drug led to significant improvements in blood flow to the lungs.

The company said it will work with the FDA to review the outlined issues and evaluate further action.