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Shares of Ardelyx Inc. (ARDX) jumped 41.7% to $7.65 ahead of the market open on Thursday, Oct. 12, after the Fremont, Calif.-based firm unveiled positive results from its second Phase 3 study of tenapanor for irritable bowel syndrome with constipation.

In the news release issued after the market close on Wednesday, Ardelyx president and CEO Mike Raab called the results a "game-changer for patients with IBS-C, their treating physicians and for Ardelyx as a company."

"These results show that tenapanor has significant potential in the market and bolsters our commitment to identify the ideal collaboration partner to help ensure that we reach the most patients possible who would benefit from therapy," Raab added.

Meanwhile, shares of Trevena Inc. (TRVN) were down 15.6% to $2 after the Chesterbrook, Pa.-based company
said it is trimming its workforce by about 30%, or 21 full-time employees, mainly from its research team. As part of the restructuring,  chief scientific officer Michael Lark, Ph.D., will leave the company in mid-December. 

Trevena said it is halting its investment in early-stage research, opting to focus its resources on the potential approval and commercialization of Olinvo (oliceridine injection) in the U.S. The firm said it plans to complete the ongoing Phase 1 study of TRV250 for acute migraine, after which it will evaluate options for further development of the asset, as well as for its series of novel S1P modulators for neuropathic pain.

The company also said its new drug application for Olinvo continues to be on pace for submission to the U.S. Food and Drug Administration this month.

Among the other biotech stock movers was Ophthotech Corp. (OPHT) , up 4.7% to $2.65.