Bristol-Myers ( BMY) jumped 6% in heavy trading after a French financial newsletter said it and Plavix partner Sanofi ( SNY) are believed to have signed a preliminary merger agreement. Sources weren't cited. Bristol-Myers rose $1.63 to $27.84 after earlier setting a 52-week high at $28.26, while Sanofi shed 55 cents to $44.79.

Par Pharmaceutical ( PRX) rose 8% after scoring final Food and Drug Administration approval of an angina drug. Par said Propranolol HCl ER is the generic equivalent of Wyeth's ( WYE) Inderal LA. Shares rose $2.06 to $26.30.

Molecular Devices ( MDCC) soared 47% after agreeing to a $35.50-a-share buyout deal with MDS ( MDZ). The pact is worth $615 million in cash. Molecular Devices rose $11.26 to $35.14, while MDS rose a dime to $17.20.

Occulogix ( OCCX) rallied 29% after the Toronto-based microcap drugmaker said the Food and Drug Administration cleared the way for a pivotal phase III study of its Rheo procedure to treat the dry form of age-related macular degeneration. Shares rose 44 cents to $1.94.

Schering-Plough ( SGP) sank 2% in robust action after posting an in-line fourth-quarter. Sales rose 14% from the same period a year earlier. Shares fell 40 cents to $24.69.

Among healthcare stocks gaining ground Monday, Cephalon ( CEPH) rose 30 cents to $74.20 and Elan ( ELN) added 3 cents to $12.38.

Among decliners, Pfizer ( PFE) dropped a dime to $26.10, Merck ( MRK) slipped 6 cents to $45.93 and Genentech ( DNA) dropped 17 cents to $86.40.