Diabetes drugs sold by Merck & Co. and Bristol-Myers Squibb Co. may double a user’s risk of developing an inflammation of the pancreas linked to cancer and kidney failure, an analysis of insurance records shows.
Patients hospitalized with pancreatitis were twice as likely to be taking Januvia, Merck’s top-selling drug, or using Bristol-Myers’s Byetta, than a control group of diabetics who didn’t have pancreatitis, according to the analysis today in the journal JAMA Internal Medicine. Both drugs increase GLP-1, a hormone that stimulates insulin production from the pancreas.
Doctors have been concerned that this category of diabetes treatments may damage the pancreas since the U.S. Food and Drug Administration said in 2007 it received a high number of reports of pancreatitis in patients taking Byetta. The agency issued a similar alert for Januvia in 2009. The study, which analyzed data from 2005 to 2008, showed a doubling in pancreatitis cases.
“This is the first real study to give an estimate of what the risk is, until now we just had a few case reports,” said Sonal Singh, the study’s author and an assistant professor of medicine at Johns Hopkins University in Baltimore. “These drugs are effective in lower glucose, but we should also consider the risk of pancreatitis and balance the risk versus the benefit.”
Merck, the second-largest U.S. drugmaker, reported $4 billion in sales, or about 9 percent of total revenue, from Januvia last year. The daily pill blocks an enzyme that breaks down GLP-1. Janumet, which combines Januvia with the older diabetes drug metformin, generated $1.7 billion in sales last year for Whitehouse Station, New Jersey-based Merck.
Bristol-Myers, based in New York, acquired Byetta when it bought Amylin Pharmaceuticals last year for about $5 billion. Byetta, which mimics GLP-1, had sales of $148 million for Bristol-Myers last year, and $159 million for Indianapolis-based Eli Lilly & Co., which ended its marketing partnership with Amylin in 2011.
“Bristol-Myers Squibb and AstraZeneca are confident in the positive benefit-risk profile of Byetta and Bydureon as demonstrated by extensive clinical trial data and safety surveillance data,” Ken Dominski, a Bristol-Myers spokesman, said in an e-mail. The companies “will continue to carefully monitor any post-marketing reports of acute pancreatitis.”
AstraZeneca Plc, based in London, has a partnership with Bristol-Myers on diabetes treatments. Bydureon is a longer acting version of Byetta.
Other drugs that increase the level of GLP-1 in the body include Bristol-Myers’s Onglyza and Novo Nordisk A/S’s Victoza. The analysis only looked at Januvia and Byetta because the other treatments weren’t on the market during the study period. Januvia was approved in the U.S. in 2006, and Byetta in 2005.
Singh said long-term studies should be done to determine if GLP-1 therapies also increase the risk of pancreatic cancer.
“We really need to know more about these drugs as pancreatitis is on the pathway to pancreatic cancer,” he said.
Merck said it has thoroughly reviewed preclinical, clinical and post-marketing safety data and found “no compelling evidence of a causal relationship between” the active ingredient in Januvia and pancreatitis or pancreatic cancer.
“Nothing is more important to Merck than the safety of our medicines and vaccines and the patients who use them,” Pam Eisele, a company spokeswoman, said in a statement.
In diabetics, pancreatitis occurs in about 3 in 1,000 patients. A doubling of that risk, such as that seen in the study, would drive that number to 6 in 1,000 for patients taking Byetta or Januvia, Singh said. About 8.6 percent of Americans, or 25 million people, had diabetes in 2010, according to data compiled by Bloomberg. The number may rise to more than 34 million by 2020.
The study looked at 1,268 diabetics who had been hospitalized with pancreatitis and compared them to the same number of patients who didn’t have the condition. Among those with pancreatitis, 87 had filled a prescription for Byetta or Januvia compared with 58 in the control group. When adjusting for variables that can make a patient more likely to develop pancreatitis, the researchers determined there was a doubling of risk, Singh said.
The study was funded by grants from Johns Hopkins, the National Center for Research Resources, and the National Institutes of Health Roadmap for Medical Research.