Monday's Health Winners & Losers

Health stocks kicked off the week on a down note amid trial news, analyst downgrades, and business updates.

Keryx Biopharmaceuticals (KERX Quote) shares plummeted $4.62, or 87.8%, to 63.8 cents after the company said a late stage study of its lead drug candidate, Sulonex, for diabetic nephropathy failed.

Elsewhere a few analyst actions moved stocks: Jeffries & Co. analyst Salveen Kochnover downgraded MannKind (MNKD Quote) to underperform from buy and dropped her price target to $4 from $20. The analyst is skeptical about the inhaled insulin market, following Eli Lilly's (LLY Quote) decision last week not to continue its program for an AIR insulin product it was developing with Alkermes (ALKS Quote) as well as Pfizer's (PFE Quote) decision to discontinue development of Exubera last fall. MannKind's lead candidate is a late-stage experimental Technosphere inhaled insulin system.

MannKind released a statement saying it's "absolutely committed to the continued development of its lead development product, Technosphere Insulin." The stock was trading down 53 cents, or 9.6%, to $4.99 on Monday.

Another downgrade: SunTrust Robinson Humphrey lowered its rating for medical device company Somanetics (SMTS Quote) to reduce from neutral. Shares were down $5.93, or 23.6%, to $19.21.

Wyeth (WYE Quote) terminated a contract with Curis (CRIS Quote) that was primarily for stroke and cardiovascular indications. Curis ended down 28 cents, or 19.6%, at $1.15.

Wyeth also announced today that it's investing $280 million to build a nutritional manufacturing facility in Suzhou Industrial Park in China's Jiangsu Province. The new facility will primarily produce infant formula milk powder and other nutritional products.

Wyeth ended down 90 cents, or 2.2%, at $40.42. It offered no help to the Amex pharmaceutical index, which was down 1% at 292.52.

Heading in the opposite direction, specialty pharmaceutical company Tongjitang Chinese Medicines (TCM Quote) said Monday that it received a proposal from its chairman and chief executive Xiaochun Wang and a director, Yongcun Chen, to acquire all of the outstanding ordinary shares of the company, including ordinary shares outstanding in the form of American depositary shares, or ADSs.

Wang and Chen offered to pay $2.55 in cash for each outstanding share of the company (or $10.20 per ADS), in a transaction under Cayman Islands law that would allow the company to become privately held. Shares rose $2.07, or 31.4%, to $8.67.