By MATTHEW PERRONE AP Business Writer WASHINGTON (AP) — Federal health regulators are looking into evidence that an Eli Lilly drug used to treat blood poisoning worsens the risk of bleeding and can lead to death in certain patients. The FDA said Wednesday a recently published study showed that the company’s drug Xigris increased the risk of dangerous internal bleeding when used by patients with a recent history of hemorrhages. Xigris is prescribed for patients with severe sepsis, or blood poisoning caused by an aggressive bacterial infection that can cause organ failure. The injectable treatment is a manmade version of a protein that occurs naturally in the human body. FDA said the drug’s labeling already warns doctors that internal bleeding is a serious side effect, but the agency plans to contact Indianapolis-based Lilly about reassessing the drug’s risks. Indianapolis-based Lilly defended the existing label Wednesday, stating “there are appropriate disclaimers in the warnings section for the physician to carefully assess the potential benefit versus risk of using Xigris.” The company also took issue with the data cited by FDA, noting they were not specifically designed to evaluate risks to patients with existing bleeding problems. In a posting to its Web site, FDA scientists acknowledged the “limitations of this study include the retrospective design — looking back at events that have already taken place — and small patient population.” The study, published in the Critical Care Medicine journal, looked at 73 sepsis patients who were treated with Xigris. Scientists found that serious internal bleeding occurred in 35 percent of patients who had risk factors for internal bleeding, compared with 3.8 percent of patients who did not. More patients with bleeding risk factors died compared with patients who did not have those risks. Regulators stressed patients should not stop taking the drug. Agency staffers plan to consult with Lilly and reevaluate the drug’s labeling in the coming months. The FDA approved Xigris in 2001, despite an evenly split vote by its advisory committee. Xigris was licensed in the European Union in 2002 under exceptional circumstances that require its license be renewed every year, with regulators evaluating new data. The drug is not a major seller for Lilly, with sales of $161 million last year, down from $183 million in 2007. In general, the FDA has begun notifying the public earlier about possible safety issues involving drugs. The policy change came after the agency was criticized for acting too slowly on information about medicines that were later removed from the market due to safety reasons. Wednesday’s announcement comes just a day after FDA’s panel of cardiology experts recommended approval for an experimental Lilly blood thinner called prasugrel. FDA has been reviewing the medication for more than a year. If approved it would become the first major competition to the blockbuster anticlotting drug Plavix, marketed by Bristol-Myers Squibb Co. and Sanofi-Aventis.