Dr. Reddy's Laboratories (RDY) sank 3.4% to $17.95 early Monday despite hitting a third-quarter earnings triple. The generic drugmaker earned 1.88 billion rupees, or $43 million. The company earned $14 million a year ago.

Amgen's ( AMGN) shares gained 2.4% to $76.04 after an analyst raised his price target on the stock, saying a competitive threat appears to be waning.

Bear Stearns analyst Mark Schoenebaum said papers filed Friday suggest that Roche's competing drug Cera is similar enough to Amgen's Epo to prevent Roche from launching Cera in the U.S. Amgen should reach a year-end price target of $83, says Schoenebaum. He previously set a price target of $77.

Shares of Chelsea Therapeutics ( CHTP) gained 6.9% after the company said U.S. regulators granted its low blood pressure drug Droxidopa orphan drug designation.

The status allows seven years of market exclusivity for the drug in the treatment of neurogenic orthostatic hypotension, a condition caused by diseases such as Parkinson's, multiple systems atrophy and pure autonomic failure. Orphan drug designation, which is granted for drugs for rare diseases affecting fewer than 200,000 patients, also provides tax credits for research costs and assistance in designing clinical trials.

Shares of Halozyme Therapeutics ( HTI) were up 8.2% to $7.56 after the company said its Enhanze technology improved the absorption of disease treatments made of large-protein molecules. The technology boosted the absorption of the injected molecules in a trial involving 15 patients, the company announced Monday. The treatment could benefit stroke patients.

AstraZeneca ( AZN) says it's investing $100 million to boost its work in developing infectious disease and cancer treatments. As a part of its plan, the pharmaceuticals company will add 100 researchers to its team of 400 existing employees who are focused on those diseases. Shares lost 1.1% to $56.15.

Among other health stock winners Monday were Novo Nordisk ( NVO), up 2.1% to $85.76; Tapestry Pharmaceuticals ( TPPH), gaining 8.6% to $1.64; and Angiotech Pharmaceuticals ( ANPI), 1.2% higher to $9.11.

Among the losers were Novartis ( NVS), down 1.7% to $57.55; Celgene ( CELG), 1.3% lower to $54.26; Biogen Idec ( BIIB), falling 2.9% to $50.35; Memory Pharmaceuticals ( MEMY), sinking 8.4% to $3.17; Bradley Pharmaceuticals ( BDY), down 2.5% to $20.78; and Keryx Biopharmaceuticals ( KERX), off 1% to $12.75.

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