Abbott Laboratories Inc. added several new warnings to the label for its rheumatoid arthritis drug Humira, according to a company letter released on Monday. Abbott, in a letter to doctors posted on the Food and Drug Administration Web site, said the FDA and the company had received “rare” reports of hypersensitivity and blood cell deficiencies, including aplastic anemia and cytopenia. When used in combination with another arthritis drug called anakinra, some serious infections were also reported. Amgen Inc. markets anakinra under the brand name Kineret. The letter, dated Nov. 5, said while the relationship between Humira and reported blood problems “remains unclear,” patients should seek medical attention if they show signs of fever, bruising or other symptoms while taking the drug.
