Popular Diabetes Drugs May Raise Pancreatic Cancer

November 12, 2012

Popular Diabetes Drugs May Raise Pancreatic Cancer

A new study has provided preliminary findings that suggest that drugs used to treat type 2 diabetes may increase the risks of several types of cancer and pancreatitis. The study was published in the medical journal Gastroenterology and was carried out by a team from theLarry L. Hillblom Islet Research Center at the University of California, Los Angeles, and was led by Dr. Peter Butler. The researchers investigated data from 2004 until 2009 provided by the U.S. Food and Drug Administration. The information related to ‘adverse events’ about drugs as reported by doctors throughout the period.

This study was carried out to build on earlier work. A study published in the medical journal Diabetes, in 2009 reported that rats that were subjected to raised levels of GLP-1 increased their chances of developing pancreatitis. GLP-1 (glucagon like peptide-1) is a hormone with an association to blood sugar levels.

The lead researcher is quoted as saying, “We have raised concern that there may be a link, but we haven’t confirmed it. We need to do more work to figure out whether this is real or not.” The researchers also acknowledge that the findings are not conclusive but say that further research should take place.

The study found that the drugs named Januvia or Byetta may increase the risk of the patient developing pancreatitis and pancreatic cancer and that Byetta may also increase the chance of developing thyroid cancer. Januvia and Byetta both work in the same manner to help control the patient’s blood sugar levels. They do this by making the body produce more GLP-1 hormone.

Byetta is an injectable drug and along with Januvia, also known as sitagliptin, are providing a new way to treat type 2 diabetes. Potentially these are superior to older drugs, however they are new which means that there is less long term data on them. Butler says, new drugs are, ‘the ones we know least about’. He also points out, “When new drugs come out, the long-term side effects of these drugs are not well understood”.

The study noted that when the new drugs were used, compared to older treatments, six times the number of cases of pancreatitis were reported. Pancreatitis is a condition where the pancreas is inflamed. Patients taking Januvia were reported to have almost three times the risk of developing pancreatic cancer, whereas Byetta had an increased risk of 2.7 times that of people who had older drugs as part of their treatment. An increase in new cases of thyroid cancer was also noted in users of Byetta.

The researchers caution that although the figures appear to show an increased risk of developing cancer if you use these drugs, it may be that doctors have just increased their rate of reporting to the FDA. Butler is pragmatic and says, “It is important to avoid alarmism and have people stop medicines that they may be benefiting from when the risk is not yet defined”. He carries on, “If the drug and you are working well together, I wouldn’t say there is any reason to stop the drug, based on the evidence we have right now. But if you have any concern you should talk to your doctor about it”.

Although the report addresses issues with drugs, Butler stresses that overweight people increase their risk of pancreatic cancer and type 2 diabetes. He points out that if people lose weight then they reduce their risk of pancreatic cancer. So his first action would be to advise people to lose weight.

Furthermore, the most common drug used to treat type 2 diabetes initially is called metformin and it is an older drug. Being an older drug means that more research has been carried out on it and it has a more robust safety profile. Additionally it is thought to reduce the risk of developing pancreatic cancer.

Dr. Mary Ann Banerji, avoids prescribing Januvia and Byetta if the patient has a family history of thyroid cancer or if the patient has ever had pancreatitis. She is a director of the Diabetes Treatment Center at SUNY Health Science Center Brooklyn in New York City and does not fully accept the data in the report. She says issues with Januvia and Byetta “should not be blown out of proportion”.

In addition she points out that there are alternatives in the form of metformin or insulin. She also includes Avandia and Actos but recent studies have uncovered an increased risk of heart failure and heart attack with these drugs. Avandia has been removed on orders from the FDA and the same agency has issued a warning concerning Actos usage and an increased risk of bladder cancer if Actos is taken for longer periods of time.

Banerji said of any drugs prescribed, “You prescribe them on an individual basis, because, in the end, all of medicine is individual”. When talking about Januvia and Byetta she says, “We should use these drugs judiciously along with metformin”.

Representatives from the pharmaceutical industry deny that any studies relating to Januvia or Byetta have found a higher risk of pancreatitis or pancreatic cancer. They say that they stand by their products. They point out that the FDA database investigated during the study holds information on doctor-reported cases. They say that it does not hold enough information to draw the conclusions that the researchers have drawn.

Dr. Barry Goldstein, vice president and therapeutic area head for diabetes and endocrinology at Merck Research Laboratories, which makes Januvia, refutes the link between Januvia and pancreatitis saying that no association has been proven. He further states, “We have full confidence in Januvia, which is used by millions of patients around the world”.

Byetta is manufactured by Amylin Pharmaceuticals and their spokesperson, Anne Erickson says that “epidemiological studies have not established a significantly increased risk of pancreatitis associated with Byetta”. She adds that, “the conclusions of the study are in contrast to other nonclinical, clinical and adequately conducted post-marketing epidemiological studies”.

An expert who was not involved with either the research or the pharmaceutical companies took a more open view. Dr. Ronald Goldberg, professor of medicine, biochemistry and molecular biology at the University of Miami Miller School of Medicine, believes that the findings deserve further consideration. He agrees that the study has limitations, but says “I don’t think the study is definitive, but it raises a flag and is clearly something we need to pay attention to going forward”. Although he accepts that presently, based on our current knowledge, “there is more benefit than risk with these drugs”.


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