Biotechnology firm Amgen Inc. said Wednesday that the Food and Drug Administration will not issue a decision this week on whether to approve a blood-clotting disorder drug.

Amgen had been expecting a decision from the FDA on the drug, called Nplate, on Wednesday. But in a statement Amgen said no decision was forthcoming giving no reason for the delay.

“Amgen continues to work with the FDA to assist in the completion of the review process,” the Thousand Oaks-based company said in a release. “We remain optimistic that a final decision will be made soon, but Amgen cannot speculate on the timing of the FDA’s response.”

An independent panel of advisers to the FDA gave the drug a positive recommendation in March. That’s a key step because the FDA generally follows its advisers’ recommendations.

However, the panel also suggested restricting the distribution due to concerns the drug might contribute to other serious blood disorders.

Though approval is still expected, Nplate will probably not be a significant revenue source for the biotech giant. Deutsche Bank estimated the drug would have peak sales of $300 million per year. Amgen racked up nearly $15 billion in sales last year.

Shares in Amgen were down 1 percent to $54.10 in early trading Wednesday.