European Regulator Finds Little Risk in Diabetes Drugs

Regulators in Europe have concluded that there was little evidence that widely used drugs to treat Type 2 diabetes could cause pancreatic inflammation or pancreatic cancer, a finding that might reassure patients while also removing a potential sales threat for Merck and some other drug companies.

“Presently available data do not confirm recent concerns over an increased risk of pancreatic adverse events with these medicines,” the European Medicines Agency said in a news release on Friday.

Both the European agency and its American counterpart, the Food and Drug Administration, have been reviewing the safety of a big class of drugs that includes Merck’s Januvia and the drugs Byetta, Bydureon and Onglyza, which are sold by Bristol-Myers Squibb and AstraZeneca.

The F.D.A. has not yet released its conclusions.

The concerns have been raised over the last few years mainly by Dr. Peter Butler, the chief of endocrinology at the University of California at Los Angeles. Dr. Butler has been hailed by some drug safety watchdogs as a hero for standing up to the drug companies but criticized by many diabetes experts as a zealot.

In his latest study, the one that triggered the reviews, Dr. Butler and colleagues examined the pancreases from 34 organ donors, some with diabetes and some without, who had died from causes other than diabetes. They found that the pancreases of the people who had used Januvia or Byetta tended to have more signs of inflammation and precancerous cellular changes than the pancreases from diabetics who had not taken those drugs and those from nondiabetics.

But the European Medicines Agency said Friday that the study had “a number of methodological limitations and potential sources of bias.” The donors who had taken Januvia or Byetta were older and had diabetes for far longer than the diabetics who had not taken the drugs, making it difficult to draw conclusions on the possible effects of the drugs.

The agency said the prescribing information for the drugs already contained warnings about pancreatic inflammation, known as pancreatitis. It said clinical trials had shown no increased risk of pancreatic cancer, though that the trials were too small to draw firm conclusions. It said “some uncertainties remain’’ regarding the long-term effects of the drugs, but much larger trials are under way to answer those questions.

The drugs involved, which the F.D.A. calls incretin mimetics and the European agency calls GLP-1-based therapies, effectively increase the body’s levels of a hormone called glucagon-, like peptide-1, which helps control blood sugar levels. Some of the drugs, known as GLP-1 agonists, mimic the effect of the hormone, while others, known as DPP-4 inhibitors, slow the breakdown of the body’s own hormone.

Collectively, the drugs had more than $9 billion in global sales last year, led by Merck’s Januvia and a related drug, Janumet, which together had sales of $5.7 billion. Other drugs include Victoza from Novo Nordisk and Tradjenta from Eli Lilly and Boehringer Ingelheim.