Curagen ( CRGN) was one of few winners of Tuesday's session. Earlier, BWS Financial upgraded the stock to strong buy from buy. Curagen was adding 44 cents, or 12.4%, to $4.

Oscient Pharmaceuticals ( OSCI) was also higher after posting a narrower-than-expected fourth-quarter loss, thanks to sales of the company's Antara cardiovascular drug. Shares of Oscient were up 15 cents, or 3%, to $5.10.

Threshold ( THLD) plummeted 57.5% after the company said late Monday that a phase III clinical trial of its drug glufosfamide failed to show the ability to extend the lives of patients with advanced pancreatic cancer. Threshold was down $2.06 to $1.52.

Drugmaker Teva Pharmaceutical ( TEVA) was lower after a study of the multiple sclerosis drug Copaxone had disappointing results. Teva was losing $2, or 5.3%, to $35.51.

Among other healthcare stocks, Chad Therapeutics ( CTU) was gaining 7 cents, or 4.1%, to $1.77; Celgene ( CELG) was losing $4.05, or 7.1%, to $53.17; Forest Laboratories ( FRX) sank $2.57, or 4.7%, to $52.55; and Amgen ( AMGN) was down $1.95, or 3%, to $64.25.

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