FDA may fine Merck for lack of diabetes study WASHINGTON (Reuters) - U.S. drug regulators may fine Merck for failing to test whether its diabetes drugs Januvia and Janumet can raise the risk of an inflamed pancreas, according to a warning letter posted online on Tuesday. Merck agreed to do a post-approval study of the drugs in mice to see if they increase the risk of acute pancreatitis, the Food and Drug Administration said in a warning letter dated February 17. Pancreatitis can be deadly if it is not treated. The FDA sometimes requires companies to conduct additional trials of a drug after it is approved to resolve any uncertainty about safety. A company that fails to comply may be fined up to "Your product is considered misbranded because you are in violation of a postmarketing requirement," Leslie Ball, acting director of the FDA's office of scientific investigations, in the letter to Merck. You have failed to comply with the approved timetable ... and failed to show good cause for not conducting the additional testing required. Merck's blockbuster pill Januvia and the related drug Janumet help lower blood sugar levels in people who have type 2 diabetes, the kind linked to poor diet and lack of exercise. The FDA approved Januvia in 2006, but later got reports of patients who developed an inflamed pancreas after taking the medicine. The agency asked Merck to study the link and see if its medicine was causing the problem. Janumet pairs Januvia's drug, known generically as sitagliptin, with a widely used, older, generic medicine called metformin, which also helps to control blood sugar. Merck has said all people with diabetes are more likely to develop pancreatitis, even without medication. But Merck agreed to give sitagliptin to mice for three months to test pancreatic safety, the FDA said. The company was supposed to submit its study design to the FDA by June 15, 2010, and submit a final report by June 15, 2011. Merck failed to submit a study design, and said it would be relying on an independent study to look at safety, even though the FDA never agreed to this, the agency said. In a statement on its website on Tuesday, Merck promised to submit a final study design to the FDA within 30 days from the time it received the FDA letter, and to start the study within six months. "Merck takes its responsibility to comply with FDA regulations very seriously, and is thoroughly reviewing its processes and procedures to ensure that Merck fulfills its commitments to the FDA going forward," the company said in the statement. An analysis of medical claims data from June 2010 showed Merck's Januvia and Byetta, by Amylin Pharmaceuticals and partner Eli Lilly & Co, posed no additional risk for an inflamed pancreas compared to other diabetes drugs. The analysis was conducted by pharmacy benefit manager Medco Health Solutions, in association with the University of Texas Southwestern Medical School. Reporting by Anna Yukhananov; Editing by Tim Dobbyn, Bernard Orr