We are no longer accepting Actos cases.
These conference call notes summarize a July 31, 2002 conversation between FDA Toxicology Team Leader Jeri El-Hage and Takeda Pharmaceuticals of North America (TPNA) in which she explained the bladder cancer link to Actos shown in non-clinical trials (studies of the drug before human testing) of similar compounds. To understand this document some background information is helpful.
Actos is in a class of drugs known as thiazolidinediones, or TZDs, which includes two other diabetes drugs with troubled histories, Avandia and Rezulin. Avandia has been withdrawn from the market in Europe and its use in the U.S. is severely restricted by the FDA due to cardiovascular problems. Rezulin was withdrawn from the market in both the U.S. and Europe after being linked to liver failure in patients taking the drug.
All three of these drugs are classified as dual PPAR agonists. The “R” in PPAR stands for receptor. These drugs work by binding to particular receptors (protein molecules) on the surface of a cell and thereby causing a change in cell activity. Dual PPAR agonists bind to two different receptors that affect glucose and cholesterol.
According to the conference call notes, El-Hage referred to the fact that development of several other dual PPAR drugs was discontinued due to the development of bladder and kidney tumors in mice. El-Hage also noted that there were no bladder “calculi” (small crystals or stones that form in the bladder) found in follow up studies of the animals. This is important because Takeda had hired a scientist to develop a hypothesis to explain why the development of tumors in rats and mice was not relevant to humans. Dr. Samuel Cohen prepared a white paper in which he argued that the tumors in rodents were the result of calculi and that it was unlikely that Actos would form calculi in humans. The hypothesis was later disproven.
In one study, 85% of the animals exposed to Actos or a comparison compound had tumor formation, without the presence of calculi. Dr. El Hage told Takeda representatives that the FDA believed the public was not being adequately informed about the bladder cancer risk associated with drugs like Actos and suggested adding language to the drug’s package insert noting that an increase in bladder tumors had been seen in other compounds in the same class as Actos. (Note: the “CAC” referenced in this document refers to the FDA’s Carcinogenicity Assessment Committee.)
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