Outspoken doctor's pancreas study prompted FDA's new diabetes-drug probe

Inconclusive data, confounding variables, as-yet-unreplicated results--they're all reasons critics have dismissed a link between incretin mimetics, a class of diabetes drugs including Merck's ($MRK) blockbuster Januvia, and pancreatic cancer. But voluntary research from watchdog groups and individuals has raised concerns within the FDA and the European Medicines Agency. Both agencies recently launched new investigations into the drugs' safety that could end up costing Big Pharma billions.

According to The New York Times, the reviews were prompted by a study by Dr. Peter C. Butler, who looked at donated organs from people who had taken Januvia and Byetta. Their pancreases tended to have more precancerous lesions. They also were heavier and exhibited faster growth of certain cells. The incretin mimetics group also comprises drugs like Victoza from Novo Nordisk ($NVO), Bydureon from Bristol-Myers Squibb ($BMY) and AstraZeneca ($AZN), and Tradjenta from Eli Lilly ($ELY) and Boehringer Ingelheim.

Potential risks for the drugs were identified years ago, not long after the first of the lot, Byetta, hit the market. In the past, the FDA has flagged the drugs for pancreatitis, including amping up warning labels on Byetta after 6 patient deaths.

According to the Times story, Byetta is facing more than 100 lawsuits, most pancreatitis-related, for 575 plaintiffs who claim they were injured from Byetta use. Another 43 suits allege Januvia caused pancreatic cancer, a particularly lethal form of the disease.

So far, it seems, sales numbers haven't suffered too much. Januvia on its own brought in $4 billion for Merck last year, while its sister combo, Janumet, added another $1.65 billion. While Byetta hasn't turned out the same financial results, it nevertheless racked up $148 million in 2012 sales for Bristol-Myers and AstraZeneca, with Eli Lilly scoring another $159 million under a marketing partnership.

Incretin mimetics-makers have defended the safety of their diabetes drugs. Nancy Thornberry, head of diabetes drug development at Merck, told the NYT that clinical trials had found no increased risk of pancreatic disease from Januvia. Other researchers agree. Dr. Robert Ratner, chief scientific and medical officer of the American Diabetes Association, called Butler's data "inconclusive" and said if excess risks existed, they would be "exceptionally low," the Times story says.

The next few months should bring some more information. In June, the National Institutes of Health will convene a meeting on the relationship between diabetes, diabetes drugs and pancreatic cancer. Butler will be a speaker there. And beginning this summer, large clinical trials with the purpose of assessing heart attack risks from these drugs should also yield information on risks for pancreatic cancer, according to the Times.

- read the NYT story here

Special Report: Top diabetes drug pipelines of 2012