Merck's Fosamax (alendronate) is a key branded drug facing generic competition in 2008. The availability of a low cost version of the market-leading osteoporosis treatment will have wide-reaching impact on the bisphosphonate class and beyond. Fosamax is slated to lose patent protection Feb. 6 and Fosamax Plus D will face generic competition two months later in April. The loss of a multi-billion blockbuster - Merck's second top-selling drug - is expected to bruise the company's top line. Merck has...