Mid-Day Gainers From December 8: Cubist Pharmaceuticals, Acceleron Pharma, Calithera Biosciences, Cempra, Isis Pharmaceuticals

Cubist Pharmaceuticals Inc CBST +35% - Shares are sharply higher as Merck announced plans to acquire Cubist for $102 per share.

Acceleron Pharma Inc XLRN+20 - The company reported positive preliminary data from its luspatercept phase 2 clinical trial.

Calithera Biosciences Inc CALA +18% - The rise in share price may be a result of the Cubist/Merck deal as the company is only valued at $206 million and in the same industry at Cubist.

Cempra Inc CEMP +8% - Shares are also trending higher amid the Merck/Cubist deal.

Isis Pharmaceuticals, Inc. ISIS +8% - On Sunday, the company reported positive phase 2 results from its study of ISIS-FXIRx. In addition, analysts at Stifel Nicolaus maintained the Buy rating and raised the price target to $65.