Byetta Cancer Side Effects May Require Strict Warnings: FDA Officials

  • Written by: Staff Writers

Federal drug safety reviewers say that the side effects of Byetta, a diabetes drug, may share thyroid cancer concerns of similar medications, which may result in black-box warning for a new long-acting version of the drug. 

In a report released earlier this month (pdf), FDA officials said animal testing revealing thyroid cancer links with Novo Nordisk’s Victoza, a long-acting diabetes treatment medication, could affect all similar drugs, including Amylin Pharmaceutical’s proposed once-weekly Byetta shot, Bydureon, also known as Byetta LAR. Therefore, strict label warnings may be necessary about the potential Byetta cancer risk to alert users to the possibility of thyroid tumors.

Byetta (exenatide) and Victoza (liraglutide) belong to the same class of drugs, known as GLP-1 analogs. The FDA report expresses concerns that all extended-release diabetes drugs belonging to that family may be linked to thyroid tumors based on tests conducted on rats and monkeys. Victoza was approved in January, but carries the black box warning on potential thyroid cancer. Amylin’s bid for approval of Bydureon was rejected by FDA last month, with the agency requesting more information before it could release the drug on the market.

In April of last year, when concerns regarding Byetta thyroid cancer side effects came up, Amylin pointed out that Victoza and Byetta are different molecules, and indicated that there was no evidence of any link between Byetta and thyroid cancer. However, a statement from company officials following the FDA report concedes that cancer concerns, while not proven, cannot be ruled out as a side effect of Byetta.

Byetta is a type 2 diabetes drug that is manufactured and distributed jointly by Amylin and Eli Lilly & Co. The drug is used to control blood sugar levels and is part of a class of medications known as incretin mimetics, which imitate natural hormones that lower blood glucose levels.

FDA drug safety reviewers have already expressed concerns that Byetta may be linked to kidney failure and a possible increased risk of pancreatitis. In November, the FDA issued a warning indicating that they have received at least 78 post-marketing reports involving Byetta kidney problems, with 62 of those reports involving users experiencing kidney failure. The alert followed FDA warnings issued in October 2007 and August 2008 of reports involving cases of pancreatitis with Byetta, including severe reports of hemorrhagic pancreatitis and necrotizing pancreatitis, which can be fatal.

Amylin and Eli Lilly also currently face a number of Byetta lawsuits involving allegations that the drug makers failed to adequately warn about the risk of pancreatitis and kidney failure.

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  1. Omamah Reply

    My Doctor started me on Beytta since January 2010 for weight loss reasons, I am not a diabetic, but it seems working well along with the Metformin Hydrocloride since I lost so much weight so far. But what is worrying me, is that Thyroid nodules are now discovered in my gland, it das FNAed twice with favoring benign nodules, But still micro follicles were seen, and I have an enlarged lymph node, 4cm, that is going to be biopsied next week!!

  2. Nancy Reply

    I was on byetta & yes I lost weight but I also got thyroid cancer. I had to have my complete thyroid removed. I was 55 years old and no family history of thyroid cancer whatsoever. I did see a warning in that byetta could cause a thyroid tumor in the mice, but nothing proven in humans. I would really like to know if anyone else has had this same situation.

  3. Dianne Reply

    I was on Byetta and was diagnosed with thyroid cancer at 56. My thyroid was removed last September and my health has been really comprimised since it was removed. My diabetes has been harder to deal with and physically I have been so exhausted that I could barely function. I have been an emotional fruitcake and told the doctor who removed the thyroid that I which it had never been necessary to take it out. No doctor ever told me that Byetta could cause thyroid cancer and I am shocked and angered over this article. Had I been warned, I would never have taken this drug. There were other medications available that could have accomplished the same result. I feel like the lab rat!

  4. Denise Reply

    I too took Byetta from 2009 and in October 2010 was also diagnosed with thyroid cancer for which I had my throid removed followed by radioactive iodine capsule as well. I haven’t felt well since, but it obviously was a necessary step.

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