The U.S. Food and Drug Administration said Monday it will require Morrisville-based Novan Inc. to conduct an additional clinical study of its lead drug.

The lead drug, a treatment of acne vulgaris, has been a drug candidate for the company for at least four years.

“We had a productive guidance meeting with the FDA regarding SB204. The meeting provided important clarity with regard to design for any future pivotal trial,” interim CEO Kelly Martin said in a statement. “We intend to update the marketplace as to the next steps for SB204 after having had the chance to review and verify the final FDA minutes and incorporate that input into the overall Novan plan.”

The FDA’s decision is the latest setback for the company.

In June, the company cut 20 percent of its workers and overhauled its executive team in a bid to turn around its fortunes. The Durham-based company said that it has enough cash to last it through the end of the year, but it will need more funding to successfully move its acne drugs, which use nitric oxide, through the approval process and get them to market.

In its 10-K for the 12 months ended Dec. 31, 2016, Novan warned shareholders of the possibility the acne-treating drug might not be approved.

The company has seen its stock fall from more than $27 per share to less than $10 per share, a mark it hasn’t moved above since.

Novan stock has fallen by more than 3.5 percent Monday, falling from $5.40 to $5.21 per share.

The press release can be found here.