WASHINGTON (Reuters)—On May 20, the U.S. Supreme Court threw out a lower court ruling that had revived hundreds of lawsuits accusing Merck & Co. of failing to properly warn patients of debilitating thigh-bone fractures as a result of taking its osteoporosis drug alendronic acid (Fosamax). The nine justices unanimously directed the Philadelphia-based 3rd U.S. Circuit…