An independent nonprofit organization that evaluates clinical and cost effectiveness of new medicines said announced prices for a just-approved class of potent cholesterol lowering drugs were far too high, according to a draft report released on Tuesday. The Boston-based Institute for Clinical and Economic Review said its analyses indicated "that the price that best represents the overall benefits" the drugs may provide patients would be between $3,615 and $4,811 a year, a 67 percent discount off the list prices.