(Reuters) - Akcea Therapeutics Inc said on Thursday it planned to cut its workforce by about 10 percent after the U.S. health regulator declined to approve its Waylivra drug for treating a genetic disease that causes fat accumulation in blood.

The company said it expected to book charges of $2 million to $2.5 million in the third quarter here, as a result of the decision, which affects only U.S. employees involved in functions focused on Waylivra.

Akcea had 270 employees prior to the announcement, the company told Reuters.

Late last month, the U.S. Food and Drug Administration had issued a complete response letter to the company for the drug, developed in partnership with Ionis Pharmaceuticals Inc.