AMLN comments on the c-cell signals seen also in LAR's preclinical studies in rats (not in monkies). No data in mice. While Byetta's preclinical data look better, LAR's preclinical data are more similar to those of liraglutide.
Amylin execs: Byetta does not carry tumor worries seen with competitor's diabetes drug
Matthew Perrone, AP Business Writer Monday April 6, 2009
WASHINGTON (AP) -- Amylin Pharmaceuticals is trying to shore up the safety image of its best-selling diabetes franchise, even as analysts speculate that tumor concerns could delay a new version of the drug.
Shares of the San Diego-based company continued to slide Monday on worries that thyroid tumors seen in animals taking a Novo Nordisk drug could slow the launch of a long-acting version of Amylin's Byetta. The drugs are from the same family of diabetes medications.
A twice-daily injection marketed with Eli Lilly & Co., Byetta is Amylin's biggest revenue driver with sales over $680 million last year. A once-weekly version of the drug is the top product in the company's pipeline.
Last week a panel of expert advisers to the Food and Drug Administration issued a split ruling on whether Novo Nordisk's injectable drug liraglutide should be approved, considering thyroid tumors seen in rat and mice studies.
Amylin executives said Monday they haven't seen any risks of cancerous tumors with Byetta, and only minimal evidence with the long-acting version, exenatide LAR, which will be submitted for FDA approval in coming months.
"Exenatide and liraglutide are distinct molecules, so it is not scientifically sound to assume that what is seen with one molecule will automatically be seen with the other," Amylin Vice President Dr. Orville Kolterman said in an interview with The Associated Press.[But the FDA considers c-cell carcinomas a class effect of the long acting GLP-1’s!]
But that point hasn't assured Wall Street analysts, who cautioned investors that exenatide LAR could be held up by additional thyroid studies requested by the FDA.
"Exenatide LAR is likely to be examined with the same scrutiny ... pushing its development timeline back from a 2010 launch, to at least 2011, or even 2012," BMO Capital Markets analyst Robert Hazlett wrote in a note Friday.
But Dr. Kolterman argued that those concerns are overblown. He pointed out that FDA officials publicly stated last week that they did not see any risk of thyroid cancer with Byetta after re-examining data on the four-year-old drug.
Additionally, animal testing of the once-weekly version of the drug did not uncover the same level of tumor risk as Novo Nordisk's drug.
Whereas liraglutide was linked to tumors in both male and female rats and mice, Kolterman said their drug was linked to tumors only in female rats. He stressed that those tumors only appeared in rats given the highest dose possible, or the equivalent of more than three times the human dose of the drug. The same tumors appeared in Novo Nordisk's animal studies at exposures comparable to human doses, Kolterman said.
Kolterman said the FDA has not requested any additional data about thyroid tumors and the company expects to submit its application in the first half of the year.
Both exenatide and liraglutide are part of a new class of drugs called GLP-1 agonists, which help control blood sugar levels by increasing insulin production and slowing sugar absorption.
Other new medications headed for the market include Onglyza, from Bristol-Myers Squibb and AstraZeneca. That drug is part of the DPP-4 inhibitor family of medications, which already includes Merck's blockbuster drug Januvia.
Some industry observers believe prescriptions for those drugs could eventually overwhelm GLP-1 drugs. They point out that DPP-4 drugs are pill-based instead of injections, and haven't shown any history of cancer or tumors.
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