**MERCK& CO INC, $45.95, down 2 pct. **TITAN PHARMACEUTICALS INC, $0.46, down 73 pct. **NEUTRAL TANDEM INC, $4.57, up 53 pct.
**MERCK& CO INC, $44.76, down 5 pct. **TITAN PHARMACEUTICALS INC, $0.34, down 80 pct. U.S. health regulators rejected an experimental drug to treat opioid addiction made by Titan Pharmaceuticals and asked for additional data showing it works, the company said.
*Mercury Computer Systems: CRT Capital raises to fair value from sell. Reuters Station users, click. 1568. Reuters Station users, click. 4899.
April 30- Mercury General Corp:. *KBW raises price target to $40 from $38. Reuters Station users, click. 1568.