The roller coaster ride for Merck shareholders and employees is on another speedy downhill run.
In barely a week, the Whitehouse Station-based drugmaker has suffered a stunning streak of setbacks.
Federal regulators rejected two experimental drugs and publicly demanded the drugmaker clean up significant problems at its main vaccine plant.
Safety questions cropped up about two other drugs made by Merck.
Share prices and are now down 35 percent since controversy struck Merck's key cholesterol franchise in mid-January.
Even its $4.85 billion settlement of tens of thousands of lawsuits over withdrawn painkiller Vioxx is dragging on, with the company saying Thursday it is extending the enrollment deadline for U.S. claimants by two months, to June 30.
Still, some analysts say Merck has the resources to withstand the rough patch.
