In light of mounting concern over Actos and bladder cancer, the U.S. Food and Drug Administration (FDA) has amped up its review of the once popular type 2 diabetes medication. First introduced by Takeda Pharmaceuticals in 1999, Actos (pioglitazone) has been the subject of increasing scrutiny over the side effects of Actos, and its causal link to bladder cancer – so much that in 2002, the FDA ordered a 10-year epidemiological study of the drug and its inherent risks. In June 2011, the federal agency issued a safety communication regarding its findings of a 40% increased risk of bladder cancer among patients who took Actos at high doses for one year or longer.
Before Actos was released on the market, early clinical trials revealed an association between pioglitazone and bladder cancer. Nevertheless, health care providers and patients were uninformed about potential bladder cancer risks, and sales of the diabetes drug skyrocketed. Over the years, medical studies conducted both in the U.S. and abroad have shown that these risks may be much greater than originally thought. New research published in the British Medical Journal suggests that individuals who take Actos may actually have an 83 percent increased chance of developing cancer.
Studies reveal Actos and bladder cancer link
Research published in the May 2012 edition of the British Medical Journal revealed the surprisingly high risk of bladder cancer among Actos users. The study analyzed data regarding more than 115,000 patients who were treated with diabetes medications from 1988 to 2009. The researchers discovered an 83 percent increased bladder cancer risk among those who took pioglitazone. Lead researcher Laurent Azoulay PhD. concluded, “Patients with type 2 diabetes and their physicians need to be fully aware of the potential association between Actos and bladder cancer.”
The American Diabetes Association (ADA) published a report in March 2011, which reviewed FDA adverse drug reports concerning Actos and bladder cancer. The report concluded that “preliminary data found an increasing risk of bladder cancer with pioglitazone exposure, with statistical significance after 24 months.”
One of the most notable studies cited in Actos lawsuits is the 10-year epidemiological trial conducted by Kaiser Permanente and overseen by the FDA. The extensive research was mandated in 2002 after early Actos studies in rats showed an increase in bladder tumors. The final results are slated to be published in late 2013, but a review of the five-year interim data prompted the FDA’s 2011 pioglitazone label update alerting consumers about the heightened risks of Actos bladder cancer.
On June 9, 2011, the French Medicines Agency decided to suspend the use of Actos after its three-year PRO-active study showed a statistically significant increase in the risk of bladder cancer in men exposed to the drug for more than a year. The study included 1.5 million patients and was conducted from 2006 to 2009. On June 10, 2011, Germany joined France in suspending the sale of Actos, and urged doctors not to prescribe the medication to any new patients. In 2011, Takeda issued a voluntary recall of Actos in France and Germany, but the type 2 diabetes medication remains on U.S. shelves.
How does Actos cause bladder cancer?
According to research from the National Cancer Institute, individuals with type 2 diabetes are already at a higher risk for developing bladder cancer. Actos belongs to a class of drugs called thiazolidinediones (TZD), which are used to help regulate blood sugar levels in diabetics because they make the body more sensitive to insulin. Cancer cells have insulin receptors, meaning they can use insulin to grow. Because Actos functions by reducing the amount of available insulin, the association between Actos and bladder cancer may be a direct effect of the way the medication works. Though scientists are unsure as to how pioglitazone provokes the development of cancerous cells within the bladder, numerous medical studies have demonstrated an elevated risk of bladder cancer among patients who ingest high doses of Actos for prolonged periods of 12 months or longer.
Risk factors for bladder cancer
In their 2011 safety announcement, the FDA warned the public that individuals who take pioglitazone for longer than a year have a 40 percent increased risk of developing Actos bladder cancer as compared to patients who did not use the medication. This warning was based on the five-year interim analysis of 193,099 diabetic patients who were treated with Actos for an average of two years. The FDA concluded that patients with the longest exposure to and the highest cumulative dose of the medication were at greater risk.
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