Merck has lost patent protection in the U.S. for cholesterol-lowering drug Zocor. This is the largest-selling drug to be open to generic competition. Three other drug companies will be legally allowed to sell simvastatin, the active ingredient in Zocor. Beginning in December 2006, companies will be allowed to make simvastatin provided that its version is chemically equivalent to Zocor. As a result, the price of a dose of simvastatin will likely drop 30% or more in the next few days, and by a...