Byetta and VictozaByetta and Victoza are two drugs of the incretin drug family. Bydureon is a long lasting version of Byetta.
What These Drugs DoByetta and Victoza are substances that mimic GLP-1, a hormone secreted by cells in the gut when people eat. GLP-1's functions include stimulating the secretion of insulin when blood sugars rise and controlling the valves that cause the stomach to empty food into the small intestine. GLP-1 passes into the brain, too, where it has effects on eating behavior and other metabolic functions that are not well understood.
Byetta and Victoza are molecules that are similar to naturally occurring GLP-1, however, changes in its molecular structure make them not break down as swiftly as naturally produced GLP-1, so their effects are longer lasting.
The original molecule that formed the basis for designing Byetta was found in the spit of Gila Lizards, hence Byetta's nickname of "Lizard Spit."
Byetta is injected and its half-life in the body is about two and a half hours, though some Byetta will remain as long as ten hours after injection.
The Fatal Flaw with These Drugs: They Cause Abnormal Cell Growth and Precancerous Tumors in the PancreasFor several years the FDA has been warning that Byetta and Victoza may be associated with pancreatitis, a painful inflammation of the pancreas that can destroy large portions of it and lead to full-fledged Type 1 diabetes. A study run by a big mail order pharmacy, Medco, which analyzed its patient's medical records appeared to suggest that Byetta was not causing pancreatitis. Acute Pancreatitis in Type 2 Diabetes Treated With Exenatide or Sitagliptin: A retrospective observational pharmacy claims analysis. Rajesh Garg et al. Diabetes Care Diabetes Care November 2010 vol. 33 no. 11 2349-2354
However, this was a relatively short study, and it was run under the auspices of a commercial organization that profits from selling this very expensive drug.
A far more conclusive, and damaging study was conducted by highly regarded researchers at UCLA's Medical School. They carefully autopsied the pancreases of people with diabetes who had died of strokes and head injuries. About half of these people had been taking an incretin drug for at least a year. While most were on Januvia, one was on Byetta. The most troubling finding of this study was that all the people with diabetes who had taken these incretin drugs for a year or more had very abnormal findings when their pancreases were examined. The abnormalities included the presence of an abnormally high number of both beta cells and alpha cells--more than three times greater than normal and the fact that these cells were arranged in "eccentric" islets that were proliferating into the pancreatic ducts in an unusual way.
The people taking these incretin drugs were also found to have tiny glandular tumors scattered throughout their pancreases.
None of the people who had had diabetes but who had not taken these drugs displayed any of these abnormalities.
The proliferative changes observed were of the type associated with pancreatitis. The tumors found in the person taking Byetta were adenomas--a type of glandular tumor that starts out benign but can over time turn cancerous.
The scientists explain in their study that it is very likely that exposure to abnormally high levels of GLP-1 or to GLP-1 mimics is what is causing these changes, citing animal research which illuminates the mechanism involved. This means any incretin drug, be it a GLP-1 mimic or a DPP-4 inhibitor will cause these dangerous changes.
They also point out that people on these drugs despite having more than three times more beta cells than normal people were still diabetic, suggesting that the newly created cells were not functioning normally. In fact, they observed that that many of the cells found showed signs they had been secreting both insulin (secreted normally by beta cells) and glucagon (secreted normally by alpha cells) . This kind of secretion pattern is characteristic only of immature cells found only in fetal tissue. It is never found in normal adult humans.
These abnormalities are very serious. More importantly, they have also been found in animals treated with these drugs, so though this is only one human study, its findings should be taken as confirming that yes, the dangerous changes seen in animals taking these drugs also occur in humans.
Since the kind of tumors found here are undetectable until they cause pancreatitis or cancer, they are very worrisome. The researchers point out in their discussion of their findings that when there is any suspicion that a person has one of these benign pancreatic tumors the treatment is immediate surgery. But what they don't mention is that suspicion that such a tumor is present only arises when it is causing clear-cut symptoms.
Unfortunately, the first symptom of spreading tumors in the pancreas is an increase in blood sugar. Since doctors consider rising blood sugars in people with diabetes to be normal, the are unlikely to suspect a tumor until other, more troubling symptoms emerge at which time it may be too late to save the patient's life.
Bottom line: All incretin drugs are hazardous to your long term health no matter what their short term benefits.
The study is found here:
Marked Expansion of Exocrine and Endocrine Pancreas with Incretin Therapy in Humans with increased Exocrine Pancreas Dysplasia and the potential for Glucagon-producing Neuroendocrine Tumors. Alexandra E Butler et al. Published online before print March 22, 2013, doi: 10.2337/db12-1686. Diabetes March 22, 2013
You can read another discussion of what this study found HERE.
These findings are so disturbing and the potential for harm so large, that I can no longer see any reason to take any drug in this family.
The rest of this page describes more about these drugs and what people taking them report. I include them for historical purposes, but urge you not to experiment with these drugs now that we know what they do to the pancreas. Whatever their benefits, it seems foolish to take any drug that could cause abnormal cell growth in your pancreas and stimulate the growth of undetectable tumors that could over time turn cancerous or cause pancreatitis requiring surgery that could damage your pancreas and take away what limited function it still has.