Abraxis BioScience Inc. said it received a warning from the U.S. Food and Drug Administration over sterilization problems at an Illinois drug plant.

The warning letter, dated Dec. 18, said drugs risk becoming contaminated due to deficiencies found during inspections in the middle of 2006.

The letter instructed the Los Angeles-based company to take “prompt action” to correct the violations found at a plant in Melrose Park, Illinois, a Chicago suburb.

Shares of Abraxis were up 24 cents to $25.45 in afternoon trading Friday.