Sumitomo Dainippon Pharma Co. Ltd.'s indirect unit Sunovion Pharmaceuticals Inc. said the U.S. Food and Drug Administration issued a complete response letter for its new drug application for SUN-101/eFlow.

The drug is used to treat airflow obstruction in patients with chronic obstructive pulmonary disease, including chronic bronchitis and/or emphysema.

Sunovion, which is not required to conduct any further clinical trials for approval of the drug, said it will work with the FDA to determine a path forward.