FDA scrutinizing Merck's Januvia, BMS' Byetta

The FDA is taking a closer look at the increased risk of Type 2 diabetics getting pancreatic cancer from the popular drugs like Merck's blockbuster Januvia and Byetta from Bristol-Myers Squibb.

The risks have been suggested since 2007, but the agency will now scrutinize unpublished data reported a month ago in JAMA's Internal Medicine, which found that patients hospitalized with pancreatitis were twice as likely to be using Januvia or Byetta compared to diabetics who didn't have pancreatitis. The agency is looking at the whole class of incretin mimetics, which work by mimicking the incretin hormones that the body usually produces naturally to stimulate the release of insulin. That also includes Victoza from Novo Nordisk ($NVO) and some others. The agency said it hasn't yet reached any new conclusions. 

When the results of a study that looked at insurance records were announced last month, both Merck ($MRK) and Bristol ($BMY) were quick to come to the defense of their drugs' safety. Bristol-Myers said it and AstraZeneca are confident in the "positive benefit-risk profile" of Byetta and its long-lasting formulation Bydureon, and promised to "continue to carefully monitor" post-marketing reports. Merck was more dismissive, telling Bloomberg that it has reviewed the data and found "no compelling evidence of a causal relationship" between Januvia and pancreatitis or pancreatic cancer.

Merck would have the most to lose from the findings. Januvia alone brought in $4 billion for Merck last year. Its sister combo treatment, Janumet, which combines Januvia with the common diabetes drug metformin, added another $1.65 billion. Byetta only sold about $310 million last year for BMS, AstraZeneca ($AZN) and Eli Lilly ($LLY), which share the drug. But BMS has high hopes for Byetta, which it picked up last year in its complicated $5.3 billion deal with AstraZeneca to buy out Amylin.  

The FDA in 2007 flagged pancreatitis cases in Byetta patients then amped up the warnings in 2008 when Byetta was tied to 6 deaths in patients who had developed pancreatitis, though four of them couldn't be causally linked to the condition. A year later, it did the same for labels on Januvia.

- here's the FDA alert