Shares of Genomic Health ( GHDX) jumped 15% to $23.85 after the company said insurer UnitedHealth ( UNH) agreed to pay for its Oncotype DX test service for breast cancer patients.

The system is designed to detect the risk of breast cancer recurrence and help predict the benefit of chemotherapy.

Shares of drugmaker Insmed ( INSM) jumped 15.5% to $1.19 Wednesday after the company said the Italian Ministry of Health wants to make its drug Iplex available to patients with Lou Gehrig's disease there.

Shares of Accentia Biopharmaceuticals ( ABPI) gained 6.3% to $4.20 after an audit of its majority-owned subsidiary Biovest International found that the company accurately disclosed information on the companies' consolidated businesses.

Merrill Lynch upgraded Sanofi-Aventis ( SNY) to buy from neutral, citing improved prospects of a legal victory and the expected launch of its obesity drug in the U.S. Shares were up 28 cents to $44.81.

Among other health stock winners Wednesday were Myriad Genetics ( MYGN), up 1.9% to $33.07; Quigley ( QGLY), gaining 7.9% to $6.43; Sunesis Pharmaceuticals ( SNSS), rising 5% to $5.24; Dyax ( DYAX), up 4.1% to $3.0; and Vertex Pharmaceuticals ( VRTX), rising 3.9% to $35.20.

Among the losers were Polydex Pharmaceuticals ( POLXF), whose shares sank 9.7% to $6.45; Dr. Reddy's Laboratories ( RDY), falling 3.1% to $17.31; Gentium ( GENT), off 1.9% to $17.64; Incyte ( INCY), down 3.8% to $6.79; Gilead Sciences ( GILD), off 1.2% to $64.22; and Schering-Plough ( SGP), falling 1.2% to $23.70.

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