More rat research -- and more scary headlines   (May 6, 2009)

A recent news story had a scary title, "Diabetes drug link to pancreatitis." I had an immediate but erroneous reaction to the headline: "it's just another story about Byetta" (Byetta has been suspected to be linked to cases of pancreatitis - see my previous discussions about Byetta and pancreatitis).I also found a press release about the study, and the press release has an even scarier title: "Popular diabetes treatment could trigger pancreatitis, pancreatic cancer."

But the research wasn't about Byetta - it was about Januvia (sitagliptin), which is a diabetes drug in an entirely different class (called DPP-4 inhibitors). And Januvia does have a mention in its label of post-marketing report(s) of pancreatitis, so this isn't exactly an unexpected finding. And most importantly, the present research was in rats with rat diabetes, not in people with type 2 diabetes.

So what's the big deal? It appears that the researchers were surprised to find a case of severe hemorrhagic pancreatitis in a sitagliptin-treated rat; but they don't really clarify whether this breed of rats (called h-IAPP transgenic rats) are prone to getting pancreatitis or the other pancreatic findings that were observed in this study (they saw findings of "increased ductal turnover" and "ductal metaplasia" in rats treated with sitagliptin, but not in rats simultaneously treated with metformin, another diabetes drug).

In my opinion, the researchers went further over the line with their speculation about humans getting pancreatic cancer from sitagliptin when they say in the published research paper that "Perhaps of most concern, increased ductal cell turnover and ductal metaplasia are also well characterized risk factors for pancreatic ductal cancer... As yet no increase in pancreatic cancer has been reported in patients treated with GLP-1 mimetics or DPP-4 inhibitors. However, these drugs have only been available for a relatively short period of time. Any influence that GLP-1 based therapy might have to increase the incidence of pancreatic cancer through chronically increased ductal cell turnover would be expected to take several years." This is simply speculation, and they readily admit "that it is possible the adverse effects observed would not occur in humans." It's totally unjustified to make a leap from a single case of pancreatitis in one lousy rat to declaring there's a risk of pancreatic cancer in humans. Tell the truth, I'm surprised the editors of the journal didn't delete this speculation.

The actual title of the actual publication in the journal Diabetes was surprisingly bland if a little confusing: Beneficial Endocrine but adverse Exocrine effects of Sitagliptin in the HIP rat model of Type 2 Diabetes, interactions with Metformin. A bland title like this one would hardly be viewed as scary. So without the scary titles of the accompanying press release and subsequent news stories, I wouldn't have had another chance to remind my readers that misleading scary headlines are not confined to the economy or politics - they are found in diabetes as well.