Amylin, which currently markets twice-daily Byetta with third partner Eli Lilly ( LLY), is also up against a competitive time crunch to get its once-weekly product approved. Its competitor Novo Nordisk ( NVO) has already submitted its application for a once-daily injection and pending the outcome of a panel in March, could have its product approved by mid-2009.

Amylin isn't the first company to face pressure from the FDA to show that products manufactured at separate plants are the same. Genzyme's ( GENZ) Myozyme produced at a new, larger-scale manufacturing facility was considered a different product than the already-approved product, causing unforeseen regulatory delays.

The potential setback disclosed in the Alkermes SEC filing on Tuesday isn't Amylin's first for the year. Amylin's shares have been depressed on reports of pancreatitis, and in some cases death, of patients taking its twice-daily Byetta, although there is no known link between the drug and pacreatitis.

Eastbourne Capital, which owned a nearly 13% stake in Amylin as of late August, said earlier in the week that it intends to hold discussions with management, other shareholders and third parties, regarding actions that could enhance shareholder value, including a possible sale of the company.

For more stories like this, check out our Biotech Stock section.

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