Byetta, Victoza Raise More Cancer FearsSep 13, 2011 | Parker Waichman LLP
A new study is adding to concerns that type 2 drugs like Byetta and Victoza could increase the likelihood that a patient will develop pancreatitis and pancreatic cancer. The study found that Byetta increases the risk for pancreatits - a known risk factor for pancreatic cancer - by six-fold, according to Bloomberg News. While Victoza, which was only approved last year, wasn't included in the study, both it and Byetta are injectable medications that belong to the same class of drugs, glucagon-like-peptide-1 (GLP-1) agonists.
The study, which was detailed in July in the journal Gastroenterology, found that Byetta, as well as Merck's Januvia, increased risks for pancreatitis and pancreatic cancer. Januvia belongs to a class of drugs called dipeptidyl peptidase-4 inhibitors, but also impacts the functioning of GLP-1.
To reach their conclusions, the scientists conducting the study analyzed reports made to the U.S. Food & Drug Administration’s Adverse Event database made between 2004 and 2009. According to Bloomberg, while their review did not prove that drugs like Byetta cause pancreatitis and pancreatic cancer, the authors said their findings indicated a need for further study.
"There are now several animal studies as well as clinical reports from humans that taken together raise concern that there may well be serious unexpected side effects of the GLP-1 class of drugs on the pancreas,” study co-author Peter Butler of UCLA, told Bloomberg via email.
The manufacturers of the drugs say the treatments are safe and there’s no evidence of increased cancer risk. However, according to Bloomberg, regulators have taken note of possible links between the new classes of diabetes drugs and pancreatitis and thyroid tumors. As we reported previously, the January 2010 approval of Victoza was controversial at the FDA because of uncertainty about its cardiovascular risks, and animal studies showing an increased risk of thyroid cancer. At the time of its approval, it was mandated that the Victoza prescribing information include a Black Box Warning about thyroid cancer risk. The FDA also stipulated that it only be used as a second-line treatment, meaning other drugs should be preferred.
In May, the Institute for Safe Medicine Practices said in its Quaterwatch report that its review of the FDA's Adverse Event Reporting database found that Victoza accounted for 70 cases of acute and chronic pancreatitis in the third quarter of 2010, and 105 cases since approval nine months earlier. Only Byetta, with 78, was the subject of more pancreatitis reports. Januvia was named in 18 reports.
According to the report, Victoza and Byetta "were triggering far more reports of pancreatitis than the oral products with a different mechanism." Unfortunately, according to the ISMP, “studies to determine the incidence, identify differences between drugs and provide the basis to weigh these risks against possible benefits have not been performed."