Amylin Pharmaceuticals, Inc. (AMLN: sentiment, chart, options) attracted a bevy of bullish option bettors today, thanks to reports that Sanofi-Aventis S.A.'s (SNY) diabetes drug may pose a safety risk. If the speculation is true, investors are hoping patients will turn to Amylin's alternative medication Byette instead.

According to data from WhatsTrading.com, AMLN has seen roughly 35,000 options change hands today nearly nine times its average daily volume of about 4,000 contracts. Of that volume, almost 80% has traded on the call side. Most notably, the equity's July 15 call has seen roughly 17,700 contracts change hands on open interest of fewer than 6,000, implying that the majority of today's volume should translate into new positions on Monday.

Today's bullish bias mimics the sentiment among short-term speculators, as indicated by the stock's Schaeffer's put/call open interest ratio (SOIR) of 0.36. Compared to similar readings taken during the past year, the security's SOIR stands just one percentage point shy of an annual optimistic peak.

Seconds from the close, the shares of AMLN have added $1.14, or 9.1%, to hang out in the $13.70 neighborhood. What's more, the stock is poised to close the month atop its 10-month moving average for the first time since October 2007.