Human Genome Sciences (HGSI: sentiment, chart, options) was the center of some brisk option trading on Wednesday, as more than 33,700 contracts crossed the tape. This volume is more than four times the stock's average daily trading volume of 8,136 contracts, according to data from WhatsTrading.com. Of that volume, more than 80% changed hands on the call side.

However, the stock's Schaeffer's put/call open interest ratio (SOIR) is sitting in the middle of the road, as traders are far from an optimistic extreme. The SOIR for HGSI rests at 0.44, which is in the 57th annual percentile rank. In other words, options players have been more optimistically aligned toward the shares 57% of the time during the past 12 months.

Meanwhile, short sellers have stocked up on the bearish bets when it comes to HGSI. During the past month, the number of HGSI shares sold short increased by 18% to 11 million, accounting for more than 8% of the company's total float. An unwinding of these pessimistic positions could fuel a significant rally in the shares.

Speaking of impressive rallies, the stock has soared more than 37% since the start of 2009. The equity has bounced off its March low of $0.57, gaining more than 400%. The security is now facing short-term resistance in the 3-3.40 region.